An interview with Ryan Madder
There is increasing concern about the damaging effects of radiation exposure to the operating room staff during interventional procedures, particularly as a recent study found that the majority of interventional cardiologists with brain tumours have left-side tumours (the side most often exposed to radiation). Ryan Madder, an interventional cardiologist at the Frederik Meijer Heart & Vascular Institute (Spectrum Health, Grand Rapids, Michigan, USA) explains why he believes a robotic system (CorPath, Corindus Vascular Robotics) for performing percutaneous coronary intervention (PCI) may help to reduce radiation exposure.
Why is radiation exposure to operators such a concern?
Radiation exposure to operators in the cath lab is hazardous for several reasons. The greatest concern is the cancer risk associated with radiation exposure. Cancer risk is linearly related to the exposure, there is no threshold below which radiation exposure is safe, and the risk of exposure is cumulative over one’s lifetime. This concern was recently highlighted by a study demonstrating that 85% of brain tumours in interventional cardiologists are left-sided, which is the side most often exposed to radiation.
Also, radiation exposure is concerning because the traditional means of protection involves wearing heavy protective lead apparel. Wearing lead clothing on a regular basis carries its own set of risks, mainly the development of chronic orthopaedic problems. For example, the risk of orthopaedic problems among interventional cardiologists has been shown to be markedly higher than in the general population and has been shown to increase with the number of years of practice. One study showed that 60% of interventional cardiologists in practice for more than 20 years had spinal problems. Such problems have the potential not only to impact quality of life but also to adversely impact the longevity of one’s career.
How can a robotic PCI system help to reduce radiation exposure?
It reduces radiation exposure to the operator by two means. Firstly, as the procedure is performed while the operator is seated in a lead-lined cockpit rather than standing next to the patient, the system increases the distance between the operator and the source of radiation. This is important because radiation exposure decreases as the square of distance from the source. In other words, if you double your distance from the source, you will decrease your exposure by a factor of four. Secondly, the lead-lined cockpit provides much better shielding of the operator from radiation than is achievable with traditional lead apparel.
What data are available for the system?
The PRECISE trial,1 which compared the robotic system with traditional PCI, found that the average radiation exposure to an operator doing standard PCI was approximately 20μGy. However, it found that the average radiation exposure during robotic PCI in this study was <1μGy—this represents a 95% reduction in radiation exposure to the operator.
What are the potential benefits of the system’s lead-lined cockpit, which enable operators to forego wearing radiation protection clothing?
Although there are no data yet regarding the long-term orthopaedic benefits of this approach, I think it could help to reduce the risk of long-term orthopaedic injuries. Speaking from my own experience doing robotic PCI procedures, I feel less joint and spinal fatigue on days in the cath lab when I do not wear lead clothing as frequently.
What is the learning curve with the system?
It is relatively easy to learn for most interventional cardiologists, which is attributable to the simple design of the robotic controls. The current system has two joysticks, one for controlling the guidewire and one for controlling the angioplasty balloon/stent catheter. As with any new technology, case selection is key when first learning to use the system. Operators should start with straightforward PCI procedures and gradually move towards more complex procedures as their experience with robotic PCI increases.
Ryan Madder has no conflicts of interests relating to Corindus Vascular Robotics
- Smilowitz et al. Journal of Invasive Cardiology 2014; 26: 318–21