New Technology is Addressing the Challenges and Future Direction of Women Interventional Cardiologists in the Cath Lab
- Volume 21 - Issue 7 - July 2013
- Posted on: 7/1/13
- 0 Comments
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Perhaps recognizing the risks, not many women physicians choose interventional cardiology, and, as a result, issues related specifically to radiation exposure in pregnancy are rarely discussed. In the United States, only 5.9 percent of interventional cardiologists are women, according to an analysis published in 2010.1
Interventional cardiologists know the risks inherent in radiation exposure and are exposed to more ionizing radiation than physicians in any other medical specialty. As such, all of us on the cath lab team, including staff, should know the steps needed to minimize risks. First, we limit exposure by being smart about the use of radiation, and second, we use mechanical solutions, such as shielding, and, if possible, robotic percutaneous coronary intervention (PCI).
Occupational challenges in the cath lab
A recent study raised our risk awareness by suggesting that interventional cardiologists may be at increased risk of developing brain cancer. Researchers in the Department of Interventional Cardiology at the Rambam Medical Center and the Technion-Israel Institute of Technology, in Haifa, documented a disproportionate number of left-sided brain tumors, suggesting a possible link between exposure to ionizing radiation and brain cancer.2
The International Commission on Radiological Protection (ICRP) and the National Council on Radiation Protection and Measurements (NCRP) recommend that pregnant women limit their exposure to ionizing radiation as much as possible. Over the course of a pregnancy, the NCRP says exposure should not exceed 5 millisieverts.
Some female interventionalists or cath lab team members may choose not to do any procedures in the cardiac catheterization lab during the first trimester or for their entire pregnancy. This decision is a personal choice and can, of course, be a difficult one to make. If a pregnant woman decides to abstain from scrubbing in the cardiac catheterization lab during pregnancy, her colleagues will be called upon to fill the gaps in the schedule. Often, in a business dominated by males, this can be a challenge for all involved. Finding a practice that will offer some flexibility in this situation is imperative for any female interventionalist or cath lab team member considering starting or expanding her family.
The February issue of Catheterization and Cardiovascular Interventions — the official journal of Society for Cardiac Angiography and Interventions (SCAI) — outlined some of the general and simple steps all interventional cardiologists and the cath lab team can take to reduce occupational exposure to radiation. These include “minimizing fluoroscopy time and the number of acquired images; using available patient dose reduction technologies; using good imaging-chain geometry; collimating; avoiding high-scatter areas; using protective shielding; using imaging equipment whose performance is controlled through a quality assurance program; and wearing personal dosimeters so that you know your dose.”3
SCAI’s Women in Innovations (SCAI-WIN) section is dedicated to fostering the development of female interventional cardiologists in training, practice, and research. For the female operator, SCAI-WIN recommends continued training in radiation protection and the use of lead shields and aprons, among other precautions. SCAI-WIN has pointed out that a 0.25-mm lead apron absorbs about 96% of scatter radiation, and a 0.5-mm lead apron absorbs about 98%.4 Other steps include limiting fluoroscopy time, avoiding extremely angulated views, reducing the number of frames per second and cine images, SCAI-WIN says, the article “Occupational Radiation Exposure: Equipment Selection for the Female Operator.”
Women should customize their protection to account for anatomical differences such as breast size, bone density, height, and weight, says SCAI-WIN, suggesting that they consider whole body shields, or at least a protective apron that provides complete chest coverage to protect the left breast, left arm, and, for pregnant women, double coverage for the ovaries and uterus. The lead should be custom fitted to provide a snug fit and avoid any gaps in protection.
All of these steps listed above can be classified under the category of being smart about radiation. Yet in their research, Roguin and colleagues point out that while lead aprons are designed to protect the trunk and thyroid, the operator’s legs, arms, neck, and head are not fully protected.
“Given that the operator’s head is, at best, incompletely protected by drop-down shielding, it would not be surprising that the left side of the brain —which is closest to radiation exposure in most interventional procedures — would be at greater risk of the induction of radiation-associated tumors,” Roguin and colleagues report. In their study,2 the researchers document that 85% of brain cancers were left sided and random chance would have produced a more equal distribution.
“We can only speculate that this disproportionate pattern of left-sided lesions reﬂects the effects of a differential dose distribution of radiation exposure in interventionists who typically work with the left side of the head in closest proximity to the primary x-ray beam and scatter,” they write. In fact, the head of the typical interventional cardiologist gets exposed to 20 to 30 mSv each year. This level of exposure is nearly 10 times greater than the level of exposure received by the entire body, researchers said.5 The left side of the head gets twice the exposure of the right side.6
Roguin and colleagues report that several studies have shown that the dosage of ionizing radiation among interventional cardiologists is higher than that of any medical staff using x-rays.
Aside from hazards of radiation exposure, another occupational hazard in interventional cardiology is back pain. After years of practice, back pain and joint problems are common. Lead aprons weigh, on average, seven to fifteen pounds and, over time, can contribute to serious painful back, neck, and spine pathology. Unlike the hazards of radiation exposure, which generally go undetected until late in life, the pain associated with carrying the weight of lead case after case, year after year, can be a constant reminder of the occupational hazard in our profession. For the reasons described above, robotic PCI is developing a niche in interventional cardiology.
In the PRECISE trial, Giora Weisz and colleagues enrolled 164 patients at nine sites, including Northeast Georgia Heart Center. PCI was completed successfully without conversion to manual operation, and device technical success was achieved in 162 of the patients (98.8%), with no device-related complications.7 The CorPath Robotic PCI system was FDA cleared in July 2012 for use in PCI.
In our practice, robotic-assisted PCI is the preferred modality for select patients. The system allows an operator to sit in a shielded cockpit to advance and position coronary guidewires, balloons, and stents, using a touch screen and joystick controls. This system allows for precise positioning of guidewires, balloons and stents. With robotic PCI, the interventionalist gets minimal radiation exposure, and just as important, the benefit of improved ergonomics. The operator can perform almost the entire procedure while seated and without wearing a lead apron.
Our practice has been fortunate to be part of a pilot study to evaluate the use of robotic-assisted angioplasties as part of the CorPath PRECISE, FDA IDE trial. The results of the trial preceded the FDA clearance of the system for use on patients in July 2012, and we have been using the CorPath System (Corindus Vascular Robotics) since that time.
The results of this multicenter study showed that a coronary intervention with a robot (in this study, the CorPath System) was safe and feasible and that radiation exposure for the operator was 95.2% lower than the levels found at the traditional table position.7
In addition, there were no device-related complications, and clinical procedural success was achieved in 160 patients (97.6%). Four patients (2.4%) had periprocedural non-Q-wave myocardial infarctions. There were no deaths, strokes, Q-wave myocardial infarctions, or revascularization in the 30 days after the procedures.
If one cardiologist is doing multiple interventions per day, and each one takes anywhere from 10 minutes to several hours or more, then the stress on the physician adds up over time, along with the exposure to radiation. Using this system, the operator benefits from improved ergonomics and greatly reduced radiation exposure. In fact, while sitting in the cockpit, the amount of radiation to the interventionalist is negligible. The system may also allow for less radiation8 and fluoroscopy time to the patient.
Robotic-assisted angioplasty in practice
For select patients in our practice, robotic-assisted PCI is the preferred modality. There are six interventional cardiologists in our 21-physician group. Each of us has been trained in robotic angioplasty, which not only decreases our radiation exposure and the time we spend on our feet wearing lead, but also helps optimize stent placement by allowing for very fine adjustments in stent position.
As we know, precision of stent placement is important to procedure outcomes.9 Not every intervention is amenable to robotic angioplasty, but the benefits to the physician and the patient are real. Over the course of weeks, months, and years, radiation exposure is cumulative. As technology addresses a positive and long-term effect on the health of interventional cardiologist while improving the precision of the procedure, robotic-assisted angioplasties have been well received in our practice.
Robotic PCI and the impact on cath lab staff
In a robotic PCI procedure, the technologist loads the equipment and injects contrast when needed. As a result, the cath lab staff remains in the room for the same amount of time for a robotic PCI procedure as he/she would in a traditional PCI procedure. As we become more comfortable with loading and unloading the equipment, we expect the cases to shorten and staff time in the room may change.
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