I am Dr. Caitlin Kennedy and I am speaking on behalf of the National Research Center for Women & Families and our president, Dr. Diana Zuckerman. Our organization is a nonprofit think tank that uses research to determine the comparative safety and effectiveness of medical products and procedures.
Our Center does not accept funding from pharmaceutical or medical device companies, so I have no conflicts of interest.
We oppose the expansion of indications for Cardiac Resynchronization Therapy Devices. We urge you to require more testing to prove that the benefits of these devices outweigh the risks for these new indications in general and for particular demographic subgroups.
The study met its success criterion, but that was mainly due to LVESVI (Left Ventricular End Systolic Volume Index) events. We agree with the FDA summary that the “clinical meaning” of these events is “not clear given that it does not appear to be a strong predictor of future heart failure urgent care events or all-cause mortality.”
In other words, there is no evidence that these devices used for this purpose are helping patients live longer or be healthier. Based on the data provided, it is impossible to say whether its benefits outweigh the risks for patients as a whole, or for particular subgroups. Although the study sample is quite large, with so few patients benefiting it is difficult to determine whether some subgroups, such as women or racial and ethnic minorities, do better or worse than others.
FDA scientists point out in their summary that the benefits are mostly in the first year. Even then, there is no difference in survival but only for heart failure urgent care events. If that benefit was robust, it would still be very important, but the absolute benefit up to year one for heart failure urgent care events is only 7.9%. In contrast, the risks include a LV lead related complication rate of 6.3%. Almost all patients who experienced a LV lead-related complication (47 of 51) needed additional surgery. That is a serious problem for these devices.
More research is needed with larger samples and more women and other subgroups to figure out whether the benefits for this indication outweigh the risks. Remember that these devices are already on the market and can be used off label, but if you recommend approval of the device for these new indications they will be more widely used despite there being no evidence that patients live longer or have any health benefits that outweigh the very serious risks, such as needing additional surgery due to LV lead-related complications.
I urge you to tell the FDA to not expand the approved indications for Medtronic cardiac resynchronization therapy devices until research has clearly shown that the benefits outweigh the risks, both overall and for women and people of color.