Aortic Stenosis, the narrowing of the aortic valve in the heart, causing restricted blood flow, is one of the most common and serious valve disease problems. A TAVR procedure is the best option for treating this disease, but recent studies have shown that approximately one-third of low flow AS patients continue to suffer with low flow AS after the procedure.
One-Third of Patients With Low Flow Aortic Stenosis Do Not Improve With TAVR, Research Finds
Patients who do not improve with TAVR are found to have worse clinical outcomes at one year
June 16, 2016 – Aortic stenosis (AS), the narrowing of the aortic valve in the heart which causes restricted blood flow, is one of the most common and serious valve disease problems. For patients with one type of AS — low flow — transcatheter aortic valve replacement (TAVR), a minimally invasive procedure which corrects the damaged aortic valve, is often the best option for restoring the heart’s normal pumping function. However, approximately one-third of low flow AS patients treated with TAVR continue to suffer persistent low flow AS even after the procedure, ultimately increasing their risk of death. Now, researchers from the Perelman School of Medicine at the University of Pennsylvania have examined this high-risk patient population to determine the cause of this persistent low flow AS and to evaluate their risk of dying during the year following the procedure. Their findings are detailed in a paper published in the Journal of the American Medical Association – Cardiology.
“There has been a lot of interest in these patients with low flow AS, as their surgical mortality is higher than other patients. TAVR is often a good option, but not all of them will be able to normalize flow following the procedure and these persistently low flow patients have a 60 percent higher rate of mortality at one year,” said Howard C. Herrmann, MD, FACC, MSCAI, John W. Bryfogle Professor of Cardiovascular Medicine and Surgery, and director of Penn Medicine’s Interventional Cardiology Program. “Low flow before TAVR is one of the most important predictors of mortality following TAVR, but it is one of the harder qualities to measure. This presents a challenge to properly treating patients with low flow AS, and can leave some patients at higher risk.”
To better understand the potential benefits of TAVR for low flow AS, researchers conducted an analysis of 984 patients with low flow AS from the PARTNER trial and continued access registry from April 2014 through January 2016. A baseline and follow-up echocardiogram, evaluation of post-TAVR hemodynamics — blood flow — and one year outcomes were assessed.
Through this analysis, researchers identified the large subgroup of patients who, following TAVR, failed to regain normal flow despite a successful procedure. In the first six months following TAVR, flow improved in roughly 66 percent of the patients evaluated. However, those with severe low flow AS had the highest mortality rate — 26 percent — at one year, as compared to approximately 20 percent for those with moderate low flow and even less for those with normal flow.
“Unfortunately, many centers do not routinely measure flow, but rather focus more on a patient’s pressure gradient or valve area when evaluating aortic stenosis pre-and post-TAVR,” said Herrmann. “While low flow is more challenging to monitor, this measurement can better inform the patient’s risk of mortality, and in turn lead to better treatment.”
The researchers noted that the identification of remedial, or treatable, causes of persistent low flow following TAVR, such as severe mitral regurgitation and atrial fibrillation, may represent an opportunity to improve the outcomes of these patients.
Venkatesh Y. Anjan, MD; Howard C. Herrmann, MD; Philippe Pibarot, PhD; William J. Stewart, MD; Samir Kapadia, MD; E. Murat Tuzcu, MD; Vasilis Babaliaros, MD; Vinod H. Thourani, MD; Wilson Y. Szeto, MD; Joseph E. Bavaria, MD; Susheel Kodali, MD; Rebecca T. Hahn, MD; Mathew Williams, MD; D. Craig Miller, MD; Pamela S. Douglas, MD; Martin B. Leon, MD. Evaluation of Flow After Transcatheter Aortic Valve Replacement in Patients With Low-Flow Aortic Stenosis: A Secondary Analysis of the PARTNER Randomized Clinical Trial. Journal of the American Medical Association — Cardiology, June 2016 DOI: 10.1001/jamacardio.2016.0759
Last year, Cath Lab Digest published an interview covering alternative access for chronic total occlusions in critical limb ischemia. J.A. Mustapha, MD, interviewed Andrej Schmidt, MD, Department of Angiology, Leipzig Heart Center, Leipzig, Germany.
Read the full article below or click the link for the original publicaiton:
CLI PERSPECTIVES: Alternative Access for CTOs in CLI
CLI Perspectives is headed by section editor J.A. Mustapha, MD,
Metro Health Hospital, Wyoming, Michigan.
Critical limb ischemia
Chronic total occlusions (CTO)
Volume 23 – Issue 2 – February, 2015
J. Mustapha: What is your preferred access method for crossing complex superficial femoral artery (SFA) CTOs, with the exception of ostial SFA disease?
A. Schmidt: Most SFA CTO crossing is performed via ipsilateral antegrade approach.
J. Mustapha: Why do you prefer an ipsilateral antegrade approach?
A. Schmidt: For multiple beneficial reasons, including shortening the distance from the access site to the CTO, enhancement of pushability, and much better wire and catheter torque.
J. Mustapha: Do you ever perform a contralateral access approach for SFA CTOs?
A. Schmidt: Yes, mostly in patients who are not good candidates for antegrade access such as obese patients, those with proximal disease, ostial SFA disease, or CTOs. Mostly, I prefer antegrade access for SFA CTOs.
J. Mustapha: Many of us have seen you perform live cases and have witnessed your excellent techniques in retrograde popliteal and SFA access in complex CTO crossing. Why do you access these segments?
A. Schmidt: We access distal to the CTO cap of the SFA or popliteal CTO only when we fail to cross from antegrade approach first. The reason we access close to the CTO is similar to the reasoning of the antegrade access, close to the CTO cap, which in turns helps with retrograde pushability and torqueability.
J. Mustapha: What advice would you give practitioners who would like to perform similar retrograde access in the SFA/popliteal?
A. Schmidt: Proceed with caution, as this should only be attempted after an antegrade approach fails. Be sure to have a balloon across the occluded target lesion and the guidewire across the distal access before taking the access catheter out, so that in case a problem (dissection, occlusion) occurs at the distal entrance, balloon angioplasty can be done to fix it. Hemostasis is principally done by external compression.
J. Mustapha: What is the average time of your balloon inflation?
A. Schmidt: The time depends on the size of the access catheter or the sheath used. Most of the time, we use the smallest catheter possible, .018-inch to .035-inch. Therefore, we perform a three-minute balloon inflation followed by an angiogram.
J. Mustapha: Is this the same for a stick in a stent vs no stent?
A. Schmidt: Yes.
J. Mustapha: Do you worry about harming the stent after getting access in it?
A. Schmidt: No. So far, in our experience, we have not had any issues with stents in these situations. Keep in mind, we only get an access in the stent in extreme cases and place the smallest catheter possible.
J. Mustapha: Moving to retrograde tibial access, which access method do you use to enter the artery, angiogram-guided or ultrasound-guided?
A. Schmidt: We use angiogram-guided access.
J. Mustapha: Which is your preferred tibial artery for retrograde access and which part of the artery do you like to enter?
A. Schmidt: My preferred artery is the anterior tibial artery and I prefer to enter it proximally.
J. Mustapha: Why proximal versus distal?
A. Schmidt: Proximally, because the vessel diameter is larger and accommodates a 4 French sheath if needed.
J. Mustapha: How do you get the access?
A. Schmidt: First we position the foot supine and support it with a rolled-up towel, then perform an angiogram in left oblique 30° view, and enter the needle thru the skin into the artery. If no blood returns, we perform an oblique view with repeat angiogram which helps show the tip of the needle and artery.
J. Mustapha: How do you obtain hemostasis after the proximal tibial access?
A. Schmidt: Most of the time, we use an external blood pressure cuff. Occasionally, we use an intra-arterial balloon.
J. Mustapha: If needed, what are your tips and tricks for getting distal tibial access?
A. Schmidt: Starting with the dorsalis pedis access, foot positioning is important. First we position the foot supine and support it with a rolled-up towel, then the C-arm is positioned at about 15° ipsilateral and 10° cranial. We then use the quick access needle holder, followed with an angiogram. Also, we can puncture and perform contrast injection simultaneously, as needed.
J. Mustapha: Do you recommend road mapping for tibial access?
A. Schmidt: No, side movements of the artery due to puncture needles are not noticed, which may lead to accidental venous access and failed attempts. Also, I don’t recommend coming in from a lateral approach.
J. Mustapha: How do you know your needle is in line with the artery?
A. Schmidt: After angiogram is done, make the needle form one line with the artery (Figure 1A-B).
J. Mustapha: What do you do in the setting of no blood return?
A. Schmidt: Obtain oblique orthogonal views at 55-65°, load the guidewire into the needle, and perform contrast injection via the proximal sheath and pull back very slowly. Keep testing if the guidewire makes it through. Another method is to pull back slowly and inject contrast from the needle holder until you see contrast in the artery, then advance the guidewire (Figure 2A-G).
J. Mustapha: Any tips on how to get peroneal access?
A. Schmidt: Start with an anterior approach. Place the C-arm at ipsilateral LAO 30° (Figure 3A), perform antegrade angiogram, and position the needle in line with the artery. If no success, then move the C-arm to right anterior oblique (RAO) 70° (Figure 3B) and repeat angiogram. Redirect the needle toward the artery, puncturing the peroneal artery through the membrana interossea.
J. Mustapha: Which puncture site is safer?
A. Schmidt: The distal tibial access approach is safer, as it is not associated with compartment syndrome.
J. Mustapha: What needles to you use for proximal and distal tibial access?
A. Schmidt: For proximal anterior tibial, posterior tibial, and peroneal access, we use a 7cm, 21g needle. For distal tibials, we use a 4cm, 21g needle.
J. Mustapha: Please advise what NOT to do in infrapopliteal retrograde access.
A. Schmidt: One should not access communication arteries, especially those off of the peroneal artery, as shown in Figure 4.
J. Mustapha: How do you minimize radiation exposure?
A. Schmidt: My angiographical approach to retrograde pedal and tibial puncture is quick and precise, minimizing radiation exposure. I attribute this to experience and the right equipment (Figure 5A). I wear a ring dosimeter (Figure 5B) to measure my exposure.
Disclosure: Dr. Mustapha reports he is a consultant to Bard Peripheral Vascular, Covidien, Cordis, CSI, Spectranetics, and Boston Scientific. Dr. Schmidt reports occasional consulting for Bard and Medtronic.
A research study was conducted in which 466 scatter radiation exposed hospital staff members were evaluated based on work-related and lifestyle information, current medications and health status. These staff members included interventional cardiologists, electrophysiologists, nurses and technicians, half of which had been working for over ten years. The results of this study concluded almost 3% of the interventional cardiology staff had a history with cancer, compared to less than 1% of unexposed comparison group. Along with that, 8% of lab workers experienced skin lesions, 30% had orthopedic illness and 5% had cataracts. These issues have all been associated with scatter radiation exposure.
McKeown, LA. “Survey Adds to Mounting Evidence That Cath Lab Work Has Radiation-Related Health Effects.”tctmd: Cardiovascular Research Foundation, 13 Apr. 2016. Web. 26 May 2016
Survey Adds To Mounting Evidence That Cath Lab Work Has Radiation-Related Health Effects
By L.A. McKeown
Wednesday, April 13, 2016
Interventional cardiologists and other personnel who work in environments with fluoroscopy-guided procedures appear to have more health problems than their colleagues in the same field who are not exposed to radiation, a survey suggests. The health problems range from eye, skin, and orthopedic problems to mental health issues, and cancers.
Researchers led by Maria Grazia Andreassi, MSc, PhD (CNR Institute of Clinical Physiology, Pisa, Italy), say “every effort should be made to raise the radiation awareness in the professional communities of interventional cardiologists and cardiac electrophysiologists, promoting justification of the examination, optimization of the dose, and maximal protection of the radiation workers.”
They surveyed 466 physicians and other staff members with an average of 10 years of experience working in interventional cardiology or electrophysiology laboratories as well as 280 individuals working in the cardiology field but having no exposure, including physicians, researchers, nurses, and administrative staff. All completed a questionnaire about their present and past medical history, medication use, duration of work, and frequency of cigarette and alcohol use. An occupational radiological risk score, which combined length of employment, individual caseload, and proximity to the radiation source, was formulated for each participant.
Physical, Psychological Differences Evident
Reporting their results online April 12, 2016, ahead of publication in Circulation: Cardiovascular Interventions, Andreassi and colleagues found that not only were potential radiation-related health issues such as skin lesions, orthopedic problems (back, neck, knee), cataracts, and cancers more prevalent in radiation-exposed vs unexposed workers, they were also more common among physicians vs technicians and nurses, and among those with longer vs shorter work histories. Across every disease category, those with 16 or more years of working in an environment with fluoroscopy-guided procedures had the highest event rates.
The prevalence of anxiety/depression was also increased among the radiation-exposed group—at a rate 6 times higher than unexposed colleagues, while the rate of thyroid disease was doubled. Radiation-exposed workers also had greater rates of hypertension and hypercholesterolemia, but not of cardiovascular events.
Rates of health problems in the radiation-exposed versus unexposed groups were confirmed in multiple logistic regression analysis.
“Unfortunately, cardiologists pay little heed to monthly or cumulative reports of radiation exposure. And recent studies confirm that simple, effective protection measures—such as a lead curtain, protection glasses and thyroid collars—are not used by the majority of exposed cardiologists,” Andreassi said in a press release.
Exposure-Related Associations Abound
Among the health problems reported in the survey and previously described in the literature, radiation-induced cancer is “the most alarming and serious” of the long-term occupational risks for interventional cardiologists, the study authors write. Concerns of brain cancer on the left side of the head, which is known to be more exposed to radiation and least protected by standard shielding, have been apparent in the literature as far back as 1998, they note.
“Although the evidence supporting an increase in radiation-induced cancer among interventional cardiologists remains inconclusive, molecular studies showed that interventional cardiologists have a two-fold increase of chromosomal damage (surrogate biomarkers of cancer risk) in circulating lymphocytes than clinical cardiologists,” Andreassi and colleagues write. Recently, findings from the International Nuclear Workers cohort showed strong evidence of positive associations between protracted low-dose radiation exposure and leukemia.
Interestingly, Andreassi and colleagues point out that radiation-related increases in hypertension and elevated serum cholesterol concentrations have also been seen in atomic-bomb survivors, more than half of whom were exposed to an average dose of < 50 mSv. In the press release, Andreassi notes that experienced, busy interventional cardiologists and electrophysiologists typically are exposed to about 5 mSv yearly. In a study published last year, her group also found that cath lab workers showed early signs of vascular aging and subclinical atherosclerosis. They suggest that chronic low-dose rate radiation “triggers changes in the endothelial cell biology that induce the onset of premature senescence, and these alterations may in part be responsible for the increased risk of chronic low-dose radiation–associated cardiovascular disease.”
As for the higher incidence of anxiety and depression in the radiation workers, Andreassi and colleagues hypothesize that this may be related to “high stress and psychological strain,” or a direct effect of radiation exposure to the head of the operator, resulting in “hippocampal neurogenesis and neuronal plasticity, with possible negative effects on mood stability and psychiatric morbidity.”
Stress a Likelier Culprit
Commenting for TCTMD, Stephen Balter, PhD, of Columbia University Medical Center (New York, NY), said the biggest flaw with the study is that everything was assumed to stem from radiation.
“It’s a high-stress job and I’m not surprised that there are health risks associated with doing the job, but these things are unlikely to be associated with radiation per se,” Balter said. “I think people trying to do the best they can are stressed out, and that’s reflected in their mental state and in their chemistry.”
Other than cataracts, which have a long, documented history in operators and others routinely exposed to occupational radiation, the other health issues such as cancers have not been substantiated in the literature as related to exposure, he added.
“The message is you have to be careful, but there’s no reason for panic,” Balter commented, adding that enforcing the wearing of radiation protection glasses and other gear among cath lab workers remains a challenge.
Profit Over People
Even though the current study is limited, there is “more than enough information for us to conclude that the interventional catheterization laboratory is not a healthy workplace,” observe Lloyd W. Klein, MD and Mugurel Bazavan, MD (Rush Medical College, Chicago, IL), in an accompanying editorial.
Despite the known risks to operators, the technology used in cath labs has outpaced safety-related changes in cath lab design and personnel protection, they say, primarily due to a profit mentality on the part of administrators that values talented, young, and inexpensive workers who can be readily replaced.
“Certainly, investing money in an innovative cath laboratory design to protect its workers is hardly cost-effective when nurturing a long career is not the goal of management,” Klein and Bazavan write. “We call on industry and hospital administration to provide responsible stewardship, and for physician societies and interventional leaders to advocate visibly and set new priorities, so that those of us who choose to help patients live a longer and healthier life can ourselves enjoy a long and healthy career, one that allows us to use all the magnificent and cherished skills we have dedicated years to master.”
Andreassi MG, Piccaluga E, Guagliumi G, et al. Occupational health risks in cardiac catheterization laboratory workers. Circ Cardiovasc Interv. 2016;Epub ahead of print.
Klein LW, Bazavan M. The economic imperatives underlying the occupational health hazards of the cardiac catheterization laboratory. Circ Cardiovasc Interv. 2016;Epub ahead of print.
Andreassi, Klein, and Bazavan report no relevant conflicts of interest.
Balter reports serving on the speakers’ bureau for Mavig, a manufacturer of radiation-protection supplies.
WORLDWIDE INNOVATIONS & TECHNOLOGIES, INC. (WIT)
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Although women are more likely to experience vascular complications in the hospital, their one-year survival rate is more favorable than men. 11,808 women and 11,884 men were evaluated over two years and the one-year mortality rate was lower in women, although the in-hospital survival rate was about the same.
Read the full article below, or click the link to see the original posting:
SCAI: Women Undergoing TAVR Have a Different Risk Profile and Greater Survival Rate Than Men
May 6, 2016 — Orlando, Fla. – Data from one of the largest national registries of transcatheter aortic valve replacement (TAVR) patients shows that although women are more likely to experience vascular complications in the hospital, their one-year survival rate is more favorable than men. This STS/ACC TVT Registry™ analysis was presented today as a late-breaking clinical trial at the Society for Cardiovascular Angiography and Interventions (SCAI) 2016 Scientific Sessions in Orlando, Fla.
Investigators evaluated in-hospital and one-year outcomes for 23,652 TAVR patients, including 11,808 women (49.9 percent) and 11,844 men (51.1 percent), from 2012-2014. Compared to men, women were older, with lower GFR (kidney function) but higher prevalence of porcelain aorta and a higher mean STS adult cardiac surgery risk score (9 percent vs. 8 percent). However, women undergoing TAVR had a lower prevalence of comorbidities, such as coronary artery disease, atrial fibrillation and diabetes.
“Prior to this study, smaller analyses have suggested that men and women have different outcomes following TAVR procedures,” said Jaya Chandrasekhar, MBBS, MRCP, FRACP, a post-doctoral research fellow with Roxana Mehran, MD, FACC, FAHA, FSCAI, at the Icahn School of Medicine at Mount Sinai and the primary author of this report. “We wanted to gain in-depth understanding into the differences between men and women undergoing TAVR procedures from the US national registry and to evaluate the discrepancies by sex in longer-term outcomes.”
The study demonstrated that women were treated more often using non-transfemoral access (45 percent vs. 34 percent) with smaller sheath and device sizes but had a higher valve cover index than men. Post-procedure, women experienced more in-hospital vascular complications than men (8.27 percent vs. 4.39 percent, adj HR 1.70, 95 percent CI 1.34 – 2.14, P < 0.001) along with a trend for more bleeding (8.0 percent vs. 5.96 percent, adj HR 1.19, 95 percent CI 0.98 – 1.44, P = 0.08).
Despite these complications for women, the in-hospital survival rate was the same as men. Additionally, one-year mortality was lower in women (21.3 percent) than in men (24.5 percent).
“These findings are promising for women,” said Dr. Chandrasekhar. “There is a suggestion that the lower rate of coronary artery disease in women undergoing TAVR does put them at an advantage for longer-term survival, compared to men. The next step should be to study quality of life metrics and outcomes beyond one year including causes for death in both men and women. At the same time, frailty should be better defined to allow appropriate selection of patients for this procedure.”
Dr. Chandrasekhar reports no disclosures.
Dr. Chandrasekhar presented “Sex Based Differences in Outcomes With Transcatheter Aortic Valve Therapy: From STS/ACC TVT Registry” on Friday, May 6, 2016, at 9:00 a.m. ET.
The Society for Cardiovascular Angiography and Interventions is a 4,500-member professional organization representing invasive and interventional cardiologists in approximately 70 nations. SCAI’s mission is to promote excellence in invasive/interventional cardiovascular medicine through physician education and representation, and advancement of quality standards to enhance patient care. SCAI’s public education program, Seconds Count, offers comprehensive information about cardiovascular disease.
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BRAIN Study Confirms Higher Radiation Dose to Cardiologists’ Left Side:
This study was conducted by Ethisham Mahmud, MD, of University of California, San Diego, along with 7cardiology fellows and 4 physicians as they performed diagnostic and interventional cardiovascular procedures to show the attenuation of radiation by using a lead-free cap. Dr. Mahmud discusses the significant amount of exposure the left time of the cranium receives compared to the right during these procedures. Dr. Mahmud says that we need to do a lot more to further understand the equipment being used and the dangers of radiation in the lab. He notes that lead-free caps are a great way to reduce scatter radiation.
BRAIN Study Confirms Higher Radiation Dose to Cardiologists’ Left Side
Single-center study looks at whether protective cap can limit radiation exposure during interventional procedures
Exposure consistently greater on left side of head; secondary operators receive more radiation than primary
By Yael L. Maxwell
Tuesday, August 18, 2015
Radiation exposure to the cranium is higher on the left than on the right side for cardiologists doing invasive procedures, though this difference can be attenuated by wearing a nonlead-based cap in the cath lab, according to a study published in the August 17, 2015, issue of JACC: Cardiovascular Interventions.
For the BRAIN (Brain Radiation Exposure and Attenuation During Invasive Cardiology Procedures) study, Ehtisham Mahmud, MD, of the University of California, San Diego (La Jolla, CA), and colleagues assessed 7 cardiology fellows and 4 attending physicians (mean age 38.4 years; all men) at their institution as they performed diagnostic and interventional cardiovascular procedures (mean 66.2 cases per operator; mean fluoroscopy time 14.9 minutes).
Each participant wore a lightweight XPF attenuating cap (BLOXR; Salt Lake City, UT) containing barium sulfate and bismuth oxide. All caps were fitted with 6 dosimeters to measure radiation exposure on the outside and inside of the cap.
A Little More on the Left
Total exposure on the outside of the cap was numerically higher on the left than center location (106.1 vs 83.1 mrad; P = .075), but exposure in both areas was higher than on the right side (50.2 mrad; P < .001 for both). Total exposure inside the cap was similar for all 3 locations—ranging from 41.8 to 42.3 mrad—and was only slightly higher than that measured by the ambient controls (38.3 mrad; P = .046).
After accounting for the ambient radiation, outside left exposure was 16 times higher than exposure on inside left and 4.7 times higher than that on the outside right (P < .001 for both). Exposure on the outside center was 11 times higher than on the inside center of the cap (P < .001), but no difference was seen between outside and inside doses on the right side.
Among a variety of factors—including patient weight, patient BMI, operator height, operator weight, percentage of radial cases, fluoroscopy time, and dose area product—only operator training level (fellow in training or attending cardiologist) predicted the extent of radiation exposure on the outside left and center locations.
Attending cardiologists—who tend to stand in the secondary position farther from the radiation source—received more outside left and center radiation than did fellows, who usually stand in the primary position (P = .002 and P = .01, respectively). “Despite the decreased exposure to the second operator as explained by the inverse square law, the optimal use of shielding in favor of the primary operator may overcome the protection offered by the increased distance,” Dr. Mahmud and colleagues suggest.
The Cap is Only the Beginning
In a telephone interview with TCTMD, Dr. Mahmud said the value of the study is “not as much about the cap as the concept.” Regardless of what protection operators may or may not use, “the most important message of this paper is that the left side of the brain gets tremendously greater exposure to radiation,” he said.
“We’re not doing a whole lot to protect ourselves… whether it’s in the primary or secondary position,” Dr. Mahmud continued. “One option is this cap, but the reality is we need to do a lot more to further understand and design equipment… or to look at alternative ways to do the procedure.”
Stephen Balter, PhD, of Columbia University Medical Center (New York, NY), told TCTMD in a telephone interview that the overall exposure reported outside the cap in the study is “reasonable” and well within the regulatory guidelines of 15,000 total mrad per year.
That said, using the cap “certainly doesn’t hurt,” he commented, and the fact that it can be used multiple times makes it less expensive than other options.
It is well known that radiation exposure is greater on the left than right side of cath lab operators, Dr. Balter explained. “It’s just how they stand and how they look at the monitors.” But “tracking people and understanding what’s happening is very relevant,” he said, adding that more specific results should come in time with theoretical modeling studies.
There will never be enough epidemiological research to show whether the XPF cap and other protections are increasing safety, Dr. Balter said. “There is a theoretical gain based on the radiobiology of models,” he added. “But it’s a small gain based on these numbers.”
All About Education
Dr. Mahmud said his team is planning another study, known as BRAIN 2, to further examine the phenomenon of how operator position affects radiation exposure. “The primary position is actually often better protected than the secondary position, where you’re a little bit further away but you might get more exposure to scatter,” he explained. “This is probably the first time this has ever been measured and ascertained.”
The second study will assess the validity of the difference between positions, Dr. Mahmud said. “We’re actually going to measure in a very systematic manner the radiation exposure for operators in the primary and secondary positions and behind and in front of shields.” BRAIN 2 will require the operators to stay in the same position throughout the course of each procedure, he explained.
But all of these studies, present and future, are meant to educate, Dr. Mahmud observed. “I am always shocked as to how few people seem to even admit that [radiation] is an issue. So I think it’s going to take more and more information, knowledge, and dissemination,” about the potential risk and any preventative options available, he said.
Reeves RR, Ang L, Bahadorani J, et al. Invasive cardiologists are exposed to greater left sided cranial radiation: the BRAIN study (Brain Radiation Exposure and Attenuation During Invasive Cardiology Procedures). J Am Coll Cardiol Intv. 2015;8:1197-1206.
Dr. Mahmud reports receiving clinical trial support from Boston Scientific, Corindus, and Gilead; serving as a consultant to The Medicines Company; and serving on the speakers bureau of Medtronic.
Dr. Balter reports no relevant conflicts of interest.
Unlike patients who are only exposed to ionized radiation during their procedure, cath lab technicians are exposed during every procedure they perform. This article discusses health effects associated with radiation exposure in the cath lab along with ways to protect the health of those technicians. Two of those ways are wearing a lead-based shield, and keeping a distance between the operator and the radiation source.
Wohns, David, and Ryan Madder. “Protecting the Provider: A Reexamination of Cath Lab Radiation Safety.” Cath Lab Digest. HMP Communications, Feb. 2015. Web. 26 May 2016.
Read the article in full below, or click the link to see the originally published article at Cath Lab Digest:
In the delivery of high-quality healthcare, patient safety is always a major concern of providers and the public. The safety of healthcare workers frequently receives significantly less attention. Recent events have highlighted this issue and are altering this perspective, with greater recognition of the sacrifices and risks that healthcare workers routinely take to perform their jobs. Patient safety remains the number-one concern of healthcare providers. However, the health and safety of providers should receive equal attention, particularly when novel techniques and strategies can be adopted to mitigate provider risk.
During 2014, the Ebola patients treated within U.S. borders caught the attention of the mainstream media and the public. Besides the public’s general concern for the patients, much attention was devoted to the healthcare workers who were exposed to the virus while caring for Ebola patients. These events raised the public’s awareness of healthcare worker safety and also caused many people to ask: “How do we ensure the safety of healthcare providers who put themselves in harm’s way to look after their patients’ health?”
This increased awareness is especially relevant to interventional cardiologists. Unlike patients, who are only exposed to ionizing radiation during their procedure, interventional cardiologists and other members of the cath lab team are repeatedly exposed to ionizing radiation, subjecting them to potentially serious long-term health issues. Additionally, the physical demands of performing their jobs while wearing heavy protective gear can lead to chronic orthopedic conditions that may prematurely end careers or force change into other fields of medicine.
With the increased interest in healthcare worker safety, it is an appropriate time to explore the risks associated with cath lab environments and novel technological solutions available to improve safety.
Assessing cath lab risks
Medical procedures performed in the cath lab are a leading source of occupational ionizing radiation exposure for medical personnel1, due to the use of fluoroscopy and cine angiography during these procedures. This occupational radiation exposure is of particular concern because today’s interventional cardiologists are spending significantly greater time in the cath lab doing more complex and lengthy procedures. Further, the performance of percutaneous coronary intervention (PCI) procedures in cath labs has increased more than 50 percent since 20002, potentially exposing interventional cardiologists to additional radiation.
Although research studies have demonstrated substantial variations in the amount of ionizing radiation to which interventional cardiologists are exposed, a look at the literature reveals the following:
One study showed that an interventional cardiologist’s head and neck area are generally exposed to approximately 20 to 30 millisieverts (mSv) per year3, which equates to 2 to 3 rems per year.
Another demonstrated that cumulative doses for the average interventional cardiologist after 30 years in the cath lab fall between 50 to 200 mSv, equivalent to 5 to 20 rems, or 2,500 to 10,000 chest x-rays.4
A third shows that interventionalists receive approximately 1 to 3 sieverts (Sv) to their head during their career (equivalent to 1,000 to 3,000 mSv, or 100 to 300 rems), which corresponds to about 500mSv to the brain5 (equivalent to 50 rems).
A separate study showed that interventional cardiologists have a radiation exposure rate documented to be two to ten times higher than that of diagnostic radiologists.4
Adverse health effects
Despite the availability and use of personal protective equipment (PPE), such as lead aprons, leaded glasses and thyroid collars, there are significant radiation exposure risks that have the potential to negatively impact the health of interventional cardiologists and their staff. Below are some findings from recent scientific literature:
Cataracts: The Occupational Cataracts and Lens Opacities in Interventional Cardiology (O’CLOC) study revealed that 50 percent of interventional cardiologists and 41 percent of cardiac cath nurses and technologists had significant posterior subcapsular lens changes, a precursor to cataracts, which is typical of ionizing radiation exposure.6
Thyroid disease: Studies have reported structural and functional changes of the thyroid as a result of radiation exposure.7 Structural changes such as malignant and benign thyroid tumors develop at a linear rate to dose exposure. Functional changes that would result in hyper- or hypo-thyroidism were noted at elevated doses of external and internal radiation exposure.7
Brain tumors and brain disease: A recent study focused on interventionalists who had been diagnosed with a variety of brain tumors. The study revealed that 86% of the brain tumors (where location is known) originated on the left side of the brain.8 This is significant, since interventional cardiologists typically stand with the left side of their body closest to the X-ray source and scattered radiation. In the general population, brain tumors originate with equal frequency on the left and right hemispheres.
Cardiovascular changes: Recent studies suggest evidence of a link between low- to moderate-dose radiation exposure and cardiovascular changes, despite personal protective wear.5
Reproductive health effects: For males, ionizing radiation has demonstrated a reduction in sperm.9 Additionally, cath lab staff members who may become pregnant while working in the cath lab must also take into consideration the effects that ionizing radiation can have on the developing fetus.
Additionally, there are orthopedic-related consequences from the heavy weight of lead gear worn by interventional cardiologists. The repeated standing and leaning over patients during procedures is fatiguing and commonly leads to chronic orthopedic conditions. A 2006 survey conducted by the Society for Cardiovascular Angiography and Interventions (SCAI) disclosed that interventional cardiologists suffer from a disproportionate amount of back, hip, and knee injuries leading to a significant amount of missed workdays.10 The weight of the personal protective gear is fatiguing, and a physician who is fatigued or experiencing discomfort may be more likely to be distracted or rush through a procedure.
Protecting the health of cath lab employees
There are two traditional techniques used to reduce radiation exposure. One is lead-based shielding, and the second is increasing the distance between the operator and the radiation source.
A relatively new approach to shielding includes devices that support lead aprons that hang from a boom, rather than being worn by clinicians. These hanging aprons provide effective radiation protection with a greater quantity of lead than is traditionally worn by operators. Since the operator is not physically supporting the lead, these devices have the potential to reduce orthopedic injuries and reduce overall operator fatigue.
The advent of robot-assisted percutaneous coronary intervention (PCI) represents another novel approach to reducing radiation exposure to operators. Robotic systems for PCI allow interventional cardiologists to perform procedures remotely, away from the patient’s bedside. Seated in a radiation-protected cockpit, the physician uses digital controls to robotically manage catheters, guide wires, angioplasty balloons, and stents to clear blockages and restore blood flow. These technologies are beneficial in reducing exposure by positioning operators further from the radiation source, but also have the potential to mitigate the impact that wearing PPE has on operators, such as orthopedic pain, missed work and disability.
The robotic-assisted PCI system being used at Spectrum Health is called CorPath (Corindus Vascular Robotics). The CorPath System allows physicians to perform PCI procedures from the comfort of a radiation-shielded cockpit that includes angiographic and hemodynamic monitors. Physicians using the system are able to take measurements, with sub-millimeter accuracy, of relevant anatomy, as well as advance or retract guide wires and/or balloon stent catheters with movements as small as a millimeter. A clinical trial has shown that using the robotic system reduced radiation exposure to the primary operator by more than 95 percent.11
Elevating healthcare worker safety
Interventional cardiology is a uniquely rewarding, highly innovative profession. The bulk of the innovation in our field over the past 3 decades has appropriately been focused on patient care. However, the manner and circumstances with which that care has been delivered in the cath lab has changed little over time. New approaches are now available to begin to mitigate the biomechanical, orthopedic, and radiation risks of working in the cath lab. The CorPath System is an example of a device with tremendous promise to reduce these hazards for interventional cardiologists, contributing to longer, healthier careers. We have been excited to bring this innovative technology to our cath labs as part of the evolution of our environment.
Sun Z, AbAziz A, Yusof AK. Radiation-induced noncancer risks in interventional cardiology: optimisation of procedures and staff and patient dose reduction. Biomed Res Int. 2013; 2013: 976962. doi: 10.1155/2013/976962.
Best PJ, Skelding KA, Mehran R, Chieffo A, Kunadian V, Madan M, et al; Society for Cardiovascular Angiography & Interventions’ Women in Innovations (WIN) Group. SCAI consensus document on occupational radiation exposure to the pregnant cardiologist and technical personnel. Catheter Cardiovasc Interv. 2011 Feb 1; 77(2): 232-241. doi: 10.1002/ccd.22877.
L Renaud. A 5-y follow-up of the radiation exposure to in-room personnel during cardiac catheterization. Health Phys. 1992 Jan; 62(1): 10-15.
Picano E, Andreassi MG, Piccaluga E, Cremonesi A, Guagliumi G. Occupational risks of chronic low dose radiation exposure in cardiac catheterisation laboratory: the Italian Healthy Cath Lab study. EMJ Int Cardiol. 2013; 1: 50-58.
Picano E, Vano E, Domenici L, Bottai M, Thierry-Chef I. Cancer and non-cancer brain and eye effects of chronic low-dose ionizing radiation exposure. BMC Cancer. 2012 Apr 27; 12: 157. doi: 10.1186/1471-2407-12-157.
Vano E, Kleiman NJ, Duran A, Romano-Miller M, Rehani MM. Radiation-associated lens opacities in catheterization personnel: results of a survey and direct assessments. J Vasc Interv Radiol. 2013 Feb; 24(2): 197-204. doi: 10.1016/j.jvir.2012.10.016.
Ron E, Brenner A. Non-malignant thyroid diseases after a wide range of radiation exposures.Radiat Res. 2010 Dec; 174(6): 877-888. doi: 10.1667/RR1953.1.
Roguin A, Goldstein J, Bar O, Goldstein JA. Brain and neck tumors among physicians performing interventional procedures. Am J Cardiol. 2013 May 1; 111(9): 1368-1372. doi: 10.1016/j.amjcard.2012.12.060.
Burdorf A, Figà-Talamanca I, Jensen TK, Thulstrup AM. Effects of occupational exposure on the reproductive system: core evidence and practical implications. Occup Med (Lond). 2006 Dec; 56(8): 516-520.
Heavy Lead Aprons Causing Pain for Cath Lab Professionals
A survey was published in March of 2015 exhibiting musculoskeletal pain caused by work-related stress due to lead aprons. In order to protect from scatter radiation, cath lab professionals are required to wear heavy lead aprons. A survey was emailed to 2,682 cardiology and radiology employees at 6 Mayo Clinic facilities in the U.S. and received responses from 57%. Of these responses, 62% of techs, 60% of nurses, 44% of attending physicians and 19% of trainees reported work-related pain. Dr. Singh recommends that these employees be rotated out of the cath lab suites more frequently to reduce stress. Additionally, he recommends lighter-weight or non-lead-based protective wear.
Dalton, Kim. “Survey Puts Spotlight on Physical Stress of Working in a Cath Lab.” Tctmd: Cardiovascular Research Foundation, 23 Feb. 2015. Web. 26 May 2016.
Read the full article below, or click the link to read the original article:
Survey Puts Spotlight on Physical Stress of Working in a Cath Lab
By Kim Dalton
Monday, February 23, 2015
Cath lab personnel who spend long hours wearing heavy lead aprons to protect against radiation exposure are more likely to experience musculoskeletal problems than colleagues who work in other hospital settings, according to the results of a survey published in the March 3, 2015, issue of the Journal of the American College of Cardiology. Cath lab staffers did not report more radiation-related cataracts and cancers, although the low prevalence of such conditions and the study’s cross-sectional design may have hampered its ability to detect a difference.
According to an accompanying editorial by James A. Goldstein, MD, of the Beaumont Health System (Royal Oak, MI), years of such physical stress can result in “missed days of work, surgery, and, in some cases, curtailed careers.”
Investigators led by Mandeep Singh, MD, of the Mayo Clinic (Rochester, MN), emailed surveys to 2,682 cardiology and radiology department employees at 6 Mayo Clinic facilities across the country and received responses from 57% (n = 554 in cardiology and 989 in radiology; average age 43 years; 33% male). Respondents were divided into cath lab workers (n = 1,042) and controls (n = 499) based on whether they reported being engaged in procedures involving radiation.
The most common occupations of respondents were:
Technician/technologist: 54.3% (mean 15.5 years in position)
Registered nurse: 18.3% (mean 16.1 years)
Physician: 13.4% (mean 18.8 years)
Other: 9.3% (mean 11.3 years)
Resident/fellow: 4.7% (mean 4.0 years)
Clinical employees with exposure to procedures involving radiation that required wearing a lead apron were more likely to have experienced work-related pain and to have sought medical care for it than the control group. In addition, they were more likely to report pain at the time of the survey (table 1).
However, there was no difference between the groups in objective assessment scores for current pain, recent use of pain medication, missed workdays, or use of disability.
The association between work-related pain and lead apron wearing remained after adjustment for age, sex, body mass index, preexisting musculoskeletal conditions, years in the profession, and job description (adjusted OR 1.67; 95% CI 1.32-2.11).
Cath lab employees who reported a history of work-related pain were more likely to be female, spent more time each week exposed to radiation, and wore a lead apron more often than controls (all P < .001). Tactics aimed at reducing musculoskeletal pain were also more common in those who reported work-related pain and included:
Prompt removal of the lead apron after procedures
Stretching/exercising before or after procedures
Wearing soft-soled shoes
There was no relationship between risk of injury and the type of lead apron worn (1 piece vs 2 pieces) or use of a glass shield or eye protection.
The likelihood of experiencing work-related pain varied by job description, with the highest incidence reported by techs (62%) and nurses (60%), followed by attending physicians (44%) and trainees (19%; P for trend < .001). Although techs and nurses were more likely than attending physicians to be female, the findings were similar when the analysis was restricted to men or women.
Cath lab workers exposed to radiation did not report more cancers, cataracts, hypothyroidism, or nephrolithiasis than employees not so exposed and showed no difference in rates of a composite endpoint including these conditions and musculoskeletal pain (P = .26).
Focus on Relieving Physical Stress
According to the authors, this is the first study to show that techs and nurses have a higher prevalence of work-related musculoskeletal pain than attending physicians despite being younger and having fewer years in the cath lab.
One reason for the discrepancy may be that physicians regularly rotate out of the cath lab while nurses and tech personnel do not, they suggest. Another possible contributor is that staff perform physically stressful tasks, like transferring patients on and off the table and applying compression after sheath removal.
According to Dr. Singh and colleagues, ongoing efforts should be made to provide regular ergonomic evaluations, periodic rotations out of the cath lab suite, and lighter-weight, non–lead-based protective wear. In addition, they say, robotic interventional equipment and remote monitoring technologies may help reduce both the number of personnel needed to care for the patient and their proximity to the radiation source, thereby diminishing the time spent wearing a lead apron.
The researchers acknowledge that these data cannot resolve questions about cancer risk from radiation exposure, in part because the incidence of the disease in younger cath lab personnel is low. Moreover, staffers diagnosed with cancer may transfer to a job that does not expose them to radiation or retire, and thus their cases would not be captured in this cross-sectional survey.
In the editorial, Dr. Goldstein calls the findings “alarming and sobering.” But, he adds, given the growth in the volume, complexity, and length of interventional procedures, the “escalating epidemic of occupational-induced orthopedic afflictions” should not be surprising.
Dr. Goldstein observes that innovative equipment that facilitate quality imaging with lower doses is helping to minimize radiation exposure, and measures like ceiling-suspended lead aprons, shielded gloves and scrub caps for cranial protection, and vascular robotic technology can help reduce orthopedic problems.
‘Take Care of Yourself’
But in a telephone interview with TCTMD, Craig St. George, RT, director of online education for the American Society of Radiologic Technologists (Albuquerque, NM), said that over 6 years working at the Mayo Clinic in Jacksonville, FL, he cannot recall anyone complaining of a work-related injury.
However, he noted, many of his colleagues exercised, stretched, and practiced yoga, which likely helped counter the stress of wearing a lead apron day after day. Another important factor in minimizing aches and pains, he suggested, was that each person was custom-fitted for an apron. And they could choose from different versions, including a wraparound model with a waist belt that took much of the weight off the shoulders. They also stood on ergonomic pads near the table to help cushion their feet during long hours. In addition, the strain of transferring patients to and from the table was mitigated by working in teams.
As for any radiation concerns, Mr. St. George said he relied on his training—making sure he was properly shielded and standing in the right place to minimize exposure—and oversight by the hospital’s radiation safety officer.
“I know people who have been technologists for 20 or 30 years, and I’ve never heard anyone say, ‘This is really wearing on me,’ he commented, adding, “You go into the profession because you want to take care of patients, and to do that you have to take care of yourself.”
Sources: 1. Orme NM, Rihal CS, Gulati R, et al. Occupational health hazards of working in the interventional laboratory: a multisite case control study of physicians and allied staff. J Am Coll Cardiol. 2015;65:820-826.
2. Goldstein JA. Orthopedic afflictions in the interventional laboratory: tales from the working wounded [editorial]. J Am Coll Cardiol. 2015;65:827-829.
Dr. Singh reports no relevant conflicts of interest.
Dr. Goldstein reports owning equity in a company developing radiation shielding equipment.
Mr. St. George reports no relevant conflicts of interest.
This article discusses a study comprising 466 hospital staff members, including interventional cardiologists, electrophysiologists, nurses and technicians who are exposed to radiation regularly. Additionally, 280 staffers who were not exposed to radiation in the cath lab were interviewed. This study gathered work-related and lifestyle information, current medications and health status for these workers. Almost three percent of interventional cardiology staff had a history of cancer, compared to less than one percent of the unexposed group. Eight percent of lab workers had experienced skin lesions, 30 percent experienced orthopedic illness and five percent had cataracts, compared to two, five, and less than one percent of the unexposed group.
See the full article below or read the original by clicking the link below:
Cath Lab Workers May Be Harmed by Radiation
Wednesday, 13 Apr 2016 08:53 AM
Healthcare workers in labs where patients undergo heart procedures guided by X-rays may be at higher risk for cataracts, skin lesions, bone disorders or cancer than other healthcare workers, according to a new study.
Procedures in the “cath lab” – named for the catheters threaded into the heart – are done for all forms of cardiac disease, like congenital heart defects, ischemic heart disease or heart arrhythmias, said lead author Maria Grazia Andreassi of the CNR Institute of Clinical Physiology in Pisa, Italy.
“These procedures, highly effective and often life-saving, require substantial radiation exposure to patients,” Andreassi told Reuters Health by email.
But staff members, too, are exposed to radiation. In particular, for the cardiologists and electrophysiologists who work near the patient and the radiation source, “the cumulative dose in a professional lifetime is not negligible,” Andreassi said.
The researchers used questionnaires to gather work-related and lifestyle information, current medications and health status for 466 exposed hospital staff, including interventional cardiologists, electrophysiologists, nurses and technicians, half of whom had been working for at least 10 years. They also surveyed 280 staffers who had not been exposed to radiation in the cath lab.
Almost 3 percent of interventional cardiology staff had a history of cancer, compared to less than 1 percent of the unexposed comparison group. Eight percent of lab workers had experienced skin lesions, 30 percent had an orthopedic illness and five percent had cataracts, compared to two percent, five percent and less than one percent of the unexposed group, respectively.
Doctors had higher risks than nurses or technicians, and risk was higher for those who had been working more than 16 years, as reported in Circulation: Cardiovascular Interventions.
Stroke and heart attack risk were similar in the radiation and non-radiation exposure groups.
“Compared to healthcare professionals not exposed to radiation, workers with more than 16 years of occupational work are approximately 10 times more likely to experience cataracts and eight times more likely to have cancer after adjusting for other confounders,” like age and smoking status, Andreassi said.
Protective measures like leaded aprons, thyroid collars, leaded glasses, and overhead radiation shields can reduce the radiation dose to the operators, but are still not used regularly in every laboratory, Andreassi said.
Healthcare workers in the cath lab “sort of know there is a risk but it’s typically presented to young people as something to know about and not to worry about,” said Dr. Lloyd Klein of Advocate Illinois Medical Center in Chicago, who coauthored an editorial accompanying the new study.
“Everyone wears lead aprons, and increasingly, lead caps,” Klein told Reuters Health by email. “We are careful about unnecessary exposure.”
But wearing lead creates orthopedic problems and doesn’t completely protect against the effects of radiation, he said.
The Occupational Safety and Health Administration and federal and state agencies probably need to get more involved than they already are, he said.
Protecting Ourselves from the Dangers of Ionizing Radiation:
Patient exposure has significantly decreased over the past decade by reducing procedure time and improved imaging quality and equipment. Despite these improvements, procedure personnel still remain at high risk of radiation exposure. Interventional cardiologists are so commonly concerned with their patient’s safety that they forget they too are at risk. These health care professionals need to know the dangers and risks associated with radiation in order to properly take charge and protect their lives. There are many hazards towards the human body with radiation exposure. These hazards include brain tumors, cataracts, thyroid disease, cardiovascular effects, and reproductive system effects. Along with that, some effects from radiation can be stochastic, like developing a malignancy, and some can be deterministic, like a skin burn. Procedure professional should be aware of their dose limits and way to reduce exposure in the lab.
The following informative article by the American College of Cardiology addresses radiation safety for the Interventional Cardiologist. Read the full text below or link to the article here:
Editorial Comment From George W. Vetrovec, MD, MACC, Editorial Team Lead for Invasive Cardiovascular Angiography and Intervention Clinical Topic Collection, ACC.org
Radiation safety is the concern of all health care providers who perform procedures associated with radiation imaging, whether for diagnostic purposes or therapeutic procedures. Appropriately, there has been increasing public and societal interest in limiting patient radiation. Likewise, laboratory personnel are at risk for radiation compounded by long procedures and multiyear careers using radiation procedures.
Over the years, there have been various equipment modifications. The initial focus was to improve image quality by increasing radiation intensity. However, there is now a greater focus on limiting patient exposure in the setting of often prolonged procedures, such as complex multivessel and chronic total occlusion (CTO) revascularization procedures. X-ray systems are able to provide excellent image quality with lower X-ray exposure.
However, despite these improvements, radiation remains a risk for procedure personnel. Unfortunately, the focus on the complexity and intensity of the procedure itself often overshadows attention to personal optimal “self-radiation” protection. The following article not only describes these risks but also, importantly, enumerates the specific operator and personnel approaches to minimize radiation risk. A review of these preventive strategies is important to re-emphasize the personnel opportunities and responsibilities for radiation protection. Finally, the authors describe some of the evolving opportunities to more dramatically reduce radiation exposure. This article is an excellent refocus on an important issue for the interventional community.
Ionizing radiation in the form of X-rays is used extensively in the modern cardiac catheterization laboratory. Unlike patients who receive a dose of ionizing radiation during their procedure, interventional cardiologists and cardiac catheterization laboratory personnel are repeatedly exposed to ionizing radiation in the course of their duties. This issue has been magnified with increased exposure in the long duration of structural or complex adult congenital heart disease intervention and CTO cases. Personnel not previously exposed to ionizing radiation such as echocardiographers, ultrasound technologists, cardiac surgeons, and anesthesiologists are frequently close to the X-ray field. Therefore, minimizing radiation exposure is of utmost importance.
Understanding the Hazards
Significant radiation exposure has the potential to impact the health and well-being of interventional cardiologists in the following ways:
Brain Tumors: A case report of brain tumors in 2 Canadian interventional cardiologists1 first raised this concern. There were three additional cases identified in a study from Sweden in physicians who had worked with fluoroscopy.2 The left-sided predisposition of these tumors raised further alarm when four additional cases were reported from France and Israel.3 Active case findings from this group highlighted this concern further when they identified that 22 of 26 cases (85%) had a left-sided distribution of brain tumors, which is a phenomenon that is not noted in the general population.4 In a study of 11 cardiologists performing invasive (diagnostic and interventional) procedures, radiation exposure to the outside left side and outside center of the head was significantly greater than the outside right side of the head (106.1 +/- 33.6 and 83.1 +/- 18.9 vs. 50.2 +/- 16.2 mrad, p < 0.001). This was significantly attenuated by the usage of a radiation protection cap (42.3 +/- 3.5 and 42.0 +/- 3.0 vs. 41.8 +/- 2.9 mrad) and only slightly higher than ambient control (38.3 +/- 1.2 mrad, p = 0.046).5
Cataracts: Higher incidence of cataracts (specifically posterior subcapsular) has been reported in interventional cardiologists in a large French multicenter observational study.6 Similar results were also noted in a separate study of both interventional cardiologists and CCL nurses and technicians. Fortunately, this risk appeared to be mitigated in those who wore lead-lined glasses.7
Thyroid Disease: Structural and functional changes as a result of radiation exposure have been reported in the thyroid gland. The degree of exposure has been correlated with a linear increase in the development of both benign and malignant thyroid neoplasms.8,9
Cardiovascular Effects: Exposure to radiation has been associated with both macrovascular and microvascular abnormalities. The occupational significance of this is not well-identified presently.10
Reproductive System Effects: Although exposure to ionizing radiation reduces both sperm count and quality, the occupational effects of this have not been determined.11 A study of 56,436 female radiology technicians in the United States revealed 1,050 cases of breast cancer and concluded that daily low-dose radiation exposure over several years may increase the risk of developing breast cancer.12 It is concerning that in the small series reported by the “Women in Innovation” group for safety, two cardiologists and one nurse with breast cancer had left-sided tumors.13Radiation safety for the pregnant interventional cardiologist and/or cardiac catheterization laboratory nurse/technician is a pressing issue. US federal law prohibits discrimination against the pregnant worker, but pregnancy should be declared to the employer as early as feasible so that adequate fetal protection can be undertaken. Protective garments must provide at least 0.5 mm lead-equivalent protection throughout the entire pregnancy, and an additional monthly fetal dose-monitoring badge should be issued and worn at waist level under the protective garment.14
Understanding Adverse Effects of Radiation Exposure
The adverse risks of radiation exposure may be described in terms of stochastic and deterministic effects.
The stochastic effect is the non-threshold biologic effect of radiation that occurs by chance to a population of persons whose probability is proportional to the dose and whose severity is independent of the dose. Developing malignancy due to radiation exposure is a stochastic risk.
The deterministic effect is a dose-dependent direct health effect of radiation for which a threshold is believed to exist. Developing a skin burn as a result of a prolonged case is a deterministic effect.
Dose exposure is usually described in terms of the following parameters:
Fluoroscopic Time (min): This is the time during a procedure that fluoroscopy is used but does not include cine acquisition imaging. Therefore, considered alone, it tends to underestimate the total radiation dose received.
Cumulative Air Kerma (Gy): The cumulative air kerma is a measure of X-ray energy delivered to air at the interventional reference point (15 cm from the isocenter in the direction of the focal spot). This measurement has been closely associated with deterministic skin effects.
Dose-Area Product (Gy.cm2): This is the cumulative sum of the instantaneous air kerma and the X-ray field area. This monitors the patient dose burden and is a good indicator of stochastic effects.
The annual occupational dose limits for catheterization laboratory personnel are as follows:
Skin or extremities
0.5 mSv/month or 5 mSv/pregnancy
Radiation-induced hair loss and injuries of the skin and subcutaneous tissues are collectively termed “tissue reactions” and are rare complications of prolonged fluoroscopic procedures. Tissue reactions may be graded; this is influenced by biological variability. In general, Grade 1 reactions are visible but seldom clinically important, but Grade 2 reactions may be clinically important. Grades 3 and 4 tissue reactions are usually considered to be clinically important.15,16
Notification levels are intended to make the operator aware, during the procedure, of the cumulative radiation used. This happens at 3 Gy. The substantial radiation dose level is a trigger level for certain processes and follow-up measures and happens at 5 Gy. It is not an indicator of a tissue reaction or a predictor of the risk of a stochastic effect but is intended to alert providers to the possibility of a tissue reaction. The following process should be followed when a substantial radiation dose level is reached:
At the end of the procedure, the primary operator documents the clinical necessity for exceeding any substantial radiation dose level in the medical record.
Patients are promptly informed when substantial amounts of radiation were used for their procedures and the necessity for this.
Patients receive follow-up to determine whether tissue reactions occurred.
If a tissue reaction is identified, the patient should be referred to an appropriate provider for management. In general, biopsies of these areas must be avoided.
These results are reported to and reviewed by the interventional service quality assurance and peer review committees.
Minimizing X-ray Exposure
This is enshrined in the “as low as reasonably achievable” (ALARA) principle. The level of protection should be the best under the prevailing circumstances, maximizing the margin of benefit over harm. Imaging requirements depend on the specific patient and the specific procedure. Although better-than-adequate image quality subjects the patient to additional radiation dose without additional clinical benefit, reducing patient radiation dose to the point at which images are inadequate is counterproductive and results in radiation dose to the patient without any clinical benefit.17Using an anthropomorphic phantom, significant differences were identified between different manufacturers in terms of radiation doses in comparable views.18
Commonly employed strategies to minimize radiation exposure are summarized below and also in Figures 1 and 2.19
Precautions to Minimize Exposure to Patient and Operator
Utilize radiation only when imaging is necessary to support clinical care. Avoid allowing the “heavy foot,” to step on the fluoroscopy pedal while not looking at the image.
Minimize use of cine. “Fluoro-save” has a <10% radiation exposure of cineangiography.
Minimize use of steep angles of X-ray beam. The left anterior oblique (LAO) cranial angulation has the highest degree of scatter exposure to the operator.
Minimize use of magnification modes. Most modern systems have software magnification algorithms that allow for magnification without additional radiation. In modern machines, there is a “Live Zoom” feature without significant degradation of the image. For example, in lieu of magnification, an 8-inch field of view with a zoom factor of 1.2 results in a 6.7-inch field of view without added radiation.
Minimize frame rate of fluoroscopy and cine. Ensure that CTOs and other long cases are performed on the 7.5 frames/sec fluoroscopy setting. A reduction of the fluoroscopic pulse rate from 15 frames/sec to 7.5 frames/sec with a fluoroscopic mode to low dose reduces the radiation exposure by 67%.
Keep the image detector close to the patient (low subject-image distance).
Utilize collimation to the fullest extent possible. In a room with a peripheral-compatible large flat panel detector, ensure that this is collimated to the field of view adequate for coronary procedures.
Monitor radiation dose in real time to assess the patient’s risk/benefit ratio during the procedure.
Precautions to Specifically Minimize Exposure to Operator
Use and maintain appropriate protective lead garments. We recommend a full protective suit with thyroid collar and additional head protection. However, 49% of active interventional operators report at least one orthopedic injury.20 Consideration should be given to ceiling suspension or floor-mounted personal radiation shielding for enhancing radiation protection and preventing orthopedic issues. For women, we also suggest additional protection to the breast with sleeves, which ensure full coverage of this area, in addition to dedicated breast shields. In view of the concern about brain tumors, protective hats are recommended, especially for the primary operator.
Maximize distance of operator from X-ray source and patient.
Keep above-table (hanging) and below-table shields in optimal position at all times. A larger ceiling-mounted shield with attached lamellae, used in combination with a drape, decreased exposure to the operator by half.21
Use additional disposable shielding material for protection from scatter radiation.
Keep all body parts out of the field of view at all times. When it is unavoidable that a body part would be exposed to radiation, consider usage of radiation attenuating gloves (for example, for an echocardiographer imaging during cardiac biopsies) or attenuating cream (for example, for an electrophysiologist attempting to perform device implantation).
A robotic percutaneous coronary intervention (PCI) system may be considered as a viable alternative for both radiation protection and occupational hazard mitigation because lead shielding need not be worn when seated in the interventional cockpit during PCI procedures.
Precautions to Specifically Minimize Exposure to Patient
Keep table height as high as comfortably possible for the operator.
Every 30 minutes, vary the imaging beam angle to minimize exposure to any specific skin area
Minimizing steep LAO and anteroposterior cranial angles
Keep the patient’s extremities out of the beam.
A radiation safety program is an essential part of the quality administration for the catheterization laboratory. This should be a collaborative effort involving physicians, staff, medical or health physicists, quality assurance personnel, and hospital administration. Interventional cardiologists are an essential part of this process and need to ensure the best possible outcomes for ourselves and for our patients.
As a profession, interventional cardiologists need to be conscious of their own radiation safety. Improved wall hanging or floor-mounted personal shielding and robotic cardiac catheterization laboratories need to become a standard of care and not a luxury. The high prevalence of orthopedic issues among catheterization laboratory professionals and subsequent disability should prompt governmental oversight agencies like the Occupational Safety and Health Administration to mandate these types of procedures and equipment. We need to continue pursuing research and development of customized radiation safety equipment for peripheral interventions and structural procedures.
Finkelstein MM. Is brain cancer an occupational disease of cardiologists? Can J Cardiol 1998;14:1385-8.
Hardell L, Mild KH, Påhlson A, et al. Ionizing radiation, cellular telephones and the risk for brain tumours. Eur J Cancer Prev 2001;10:523-9.
Roguin A, Goldstein J, Bar O. Brain tumours among interventional cardiologists: a cause for alarm? Report of four new cases from two cities and a review of the literature. EuroIntervention 2012;7:1081-6.
Roguin A, Goldstein J, Bar O, et al. Brain and neck tumors among physicians performing interventional procedures. Am J Cardiol 2013;111:1368-72.
Reeves RR, Ang L, Bahadorani J, et al. Invasive cardiologists are exposed to greater left sided cranial radiation: The BRAIN study (Brain Radiation Exposure and Attenuation during Invasive Cardiology Procedures). JACC Cardiovasc Interv 2015;8:1197-206.
Jacob S, Boveda S, Bar O, et al. Interventional cardiologists and risk of radiation-induced cataract: results of a French multicenter observational study. Int J Cardiol 2013;167:1843-7.
Vano E, Kleiman NJ, Duran A, et al. Radiation-associated lens opacities in catheterization personnel: results of a survey and direct assessments. J Vasc Interv Radiol 2013;24:197-204.
Ron E, Brenner A. Non-malignant thyroid diseases after a wide range of radiation exposures. Radiat Res 2010;174:877-88.
Schneider AB, Ron E, Lubin J, et al. Dose-response relationships for radiation-induced thyroid cancer and thyroid nodules: evidence for the prolonged effects of radiation on the thyroid. J Clin Endocrinol Metab 1993;77:362-9.
Picano E, Vano E, Domenici L, et al. Cancer and non-cancer brain and eye effects of chronic low-dose ionizing radiation exposure. BMC Cancer 2012;12:157-69.
Burdorf A, Figà-Talamanca I, Jensen TK, et al. Effects of occupational exposure on the reproductive system: core evidence and practical implications. Occup Med (Lond) 2006;56:516-20.
Doody MM, Freedman DM, Alexander BH, et al. Breast cancer incidence in U.S. radiologic technologists. Cancer 2006;106:2707-15.
Buchanan GL, Chieffo A, Mehilli J, et al. The occupational effects of interventional cardiology: results from the WIN for Safety survey. EuroIntervention 2012;8:658-63.
Best PJ, Skelding KA, Mehran R, et al. SCAI consensus document on occupational radiation exposure to the pregnant cardiologist and technical personnel. Catheter Cardiovasc Interv 2011;77:232-41.
Balter S, Hopewell JW, Miller DL, et al. Fluoroscopically guided interventional procedures: a review of radiation effects on patients’ skin and hair. Radiology 2010;254:326-41.
National Council on Radiation Protection and Measurements. Radiation Dose Management for Fluoroscopically Guided Interventional Medical Procedures, NCRP Report No. 168. Bethesda: NRCP Publications; 2010.
Cousins C, Miller DL, Bernardi G, et al. ICRP PUBLICATION 120: Radiological protection in cardiology. Ann ICRP 2013;42:1-125.
Christopoulos G, Christakopoulos GE, Rangan BV, et al. Comparison of radiation dose between different fluoroscopy systems in the modern catheterization laboratory: results from bench testing using an anthropomorphic phantom. Catheter Cardiovasc Interv 2015;86:927-32.
Chambers CE, Fetterly KA, Holzer R, et al. Radiation safety program for the cardiac catheterization laboratory. Catheter Cardiovasc Interv 2011;77:546-56.
Klein LW, Tra Y, Garratt KN, et al. Occupational health hazards of interventional cardiologists in the current decade: results of the 2014 SCAI membership survey. Catheter Cardiovasc Interv 2015;86:913-24.
Gilligan P, Lynch J, Eder H, et al. Assessment of clinical occupational dose reduction effect of a new interventional cardiology shield for radial access combined with a scatter reducing drape. Catheter Cardiovasc Interv 2015;86:935-40.
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Interventional cardiologist Dr. John Wang, chief of the Cardiac Catheterization Lab at MedStar Union Memorial Hospital in Baltimore, Maryland demonstrates a new technique to cardiac catheterization procedure by using transradial access.
Patients may need a cardiac catheterization if they are experiencing cholesterol narrowing’s in the blood vessels which may result in chest pain or even a heartattack. This procedure is typically performed through the femoral artery, but there is sufficient collateral blood flow to the hand to make the wrist an accessible location for catheterization. There is no risk of bleeding complications where the catheter is inserter so this technique is used to increase patient comfort and experience a quicker recovery. If the patient is in need of a stent, this can be placed through the wrist as well.
Link to demonstration video:
Dr. John Wang also discusses the benefits of transradial cardiac catheterization: