Raj Makkar, MD, Director, Interventional Cardiology and Cardiac Catheterization Laboratory, Associate Director of Cedar-Sinai Heart Institute.
Interview conducted by Ivanhoe Broadcast News in July 2017.
Tell us a little bit about what the Sentinel device does for patients having their valves replaced.
Dr. Makkar: The Sentinel device is a cerebral protection device which is used during transcatheter aortic valve replacement. Over the last few years, transcatheter aortic valve replacement has become very popular because it is less invasive. We can replace a patient’s narrow aortic valves or leaky aortic valve, in some cases, without open heart surgery. The Sentinel device offers protection against the debris entering the brain when we are performing the transcatheter aortic valve replacement or TAVR procedure.
How does the debris enter the brain?
Dr. Makkar: The narrow aortic valve in aortic stenosis has a lot of calcium deposit. Also, patients who have a narrow aortic valve tend to have plaque and debris in their aorta. When we perform the transcatheter aortic valve replacement, or for that matter, when the surgeon replaces the aortic valve during open heart surgery, some of this material can break loose and go into the brain.
How often does this happen?
Dr. Makkar: What we know is that some degree of material is going into the brain and showing up on sophisticated imaging, such as cardiac MRI, almost 70 to 80 percent of the time, either during open heart surgery or during the TAVR procedure.
But would it necessarily cause a stroke?
Dr. Makkar: We also know is that the incidence of stroke is much less than 70 percent. Not all patients who have debris experience a stroke. But nonetheless, I think it’s a good idea to prevent debris going into the brain, even if it doesn’t cause a stroke. It might have some impact on the long term health of the brain. I think that it is important to undertake measures and to use precautions that minimize debris going to the brain; this seems to be a prudent idea when doing both TAVR and surgical aortic valve replacement.
How do you implant the Sentinel device?
Dr. Makkar: There are two filters in the device, and they are both incorporated into a catheter. When the patient is asleep or ready for the TAVR procedure, we will insert this catheter through the right radial artery, essentially through a very narrow puncture. It just adds maybe five minutes to the procedure, and it is very successful. It is safely placed in 90 to 95 percent of patients during the procedure. One of the filters goes into the big artery that supplies one side of the brain, and then we go ahead and deploy the other filter which goes into the left carotid artery. This insures that the filters are deployed into the major arteries going to the brain. These filters stay there while we are doing our work and changing the heart valve, so that the debris is captured by the filters, rather than going into the brain. When the procedure is completed, we will go ahead and retrieve these filters. It’s very common for us to capture material when we take the Sentinel device out; it is not uncommon to see the clot or a piece of calcium in the filter.
The study is completed, so what did your study show?
Dr. Makkar: That is correct. The FDA approved the device now based on the study that was conducted. The SENTINEL trial showed that in the first 30 days, the stroke rates were decreased by 40 percent. However, the true efficacy of the filter is demonstrated in what we call the peri-procedural time, or the first 72 hours. If you look at the first 72 hours, the stroke rates were diminished by almost two-thirds. Within the first 72 hours the stroke rates decreased by 62, 63 percent because we are removing the filter from the patient at the end of the procedure. That’s quite significant. The data speaks for itself and prompted the FDA to approve the device. I think it’s also important to mention that when you look at the efficacy of a device, you also have to look at the safety of the device. By and large, the Sentinel device is safe. It can be easily placed, and it can also be incorporated into the work flow of the busy cath lab where a lot of these procedures are actually done. It’s safe, it is effective, and it reduces strokes by two-thirds. At our institution, we incorporate the Sentinel when we do our TAVI or TAVR procedures.
Is everyone eligible or are there patients who shouldn’t have this?
Dr. Makkar: Our goal should be to reduce strokes in every patient, but there are certain anatomical constraints and it’s essential that the anatomy of the aortic arch is defined before you use this procedure. We have to ensure that there is not a lot of calcium or tortuosity. I would say that 90 percent of the patients in our early clinical experience seem to be favorable for this device and we can deploy this device within a very reasonable period.
So every patient should ask their doctor about it?
Dr. Makkar: I think it’s reasonable to ask physicians to learn how to use this device, as well as incorporate this device with the TAVR procedure.
Is this something that’s available nationwide yet?
Dr. Makkar: This device has just been approved by the FDA, and that is a start. I do think that it is going to take time to train more physicians, and for the device to get incorporated into many cath labs. But I think that as time goes by, more and more centers will get access to this device and will learn how to use this device. Our institution participated in the early clinical trial so we do have experience with this device. We knew how to use the device and of course, the company chose Cedar-Sinai as one of its early institutions to launch the device after commercial approval.
What about Robert our patient – what is his story, what can you tell us about him?
Dr. Makkar: Robert has an amazing story. He was extremely sick; he had poor heart muscle function, a significant clot in his left ventricle, and he had very tight aortic stenosis. This was a double jeopardy in the sense that his heart was fragile, and there was a clot within the left ventricle. Thus, a TAVI procedure was fraught with danger because we could run the risk of releasing the debris from the valve itself, which occurs with practically every patient, and the debris could go into the brain. Also, the big clot in the left ventricle was at a significant risk of going into the brain. We were able to replace his aortic valve safely without having a stroke. Since then he’s doing well, his heart muscle function has significantly improved, his valve is working well, and his coronary artery blockages has been fixed. His doctor used to call him a “dead man walking,” and I can tell you he’s quite alive and doing great. He is thriving, and we are very pleased about that.
What else haven’t I asked you about the procedure and the study that you think should be included?
Dr. Makkar: It is important to remember that whenever material goes into the brain, it is common for subtle brain injury to occur, whether they are surgical procedures or catheter-based procedures. Furthermore, I think that every effort that we can undertake to reduce this is worthwhile. Also, there are other companies that are testing different devices that could be effective in the future. But currently, this is the only device that is FDA approved. As we move forward, I’m hoping that there will be other options and more research about reducing cerebral embolization and brain injury.
Prior to the Sentinel, were you only able to hope that the debris wouldn’t go to the brain?
Dr. Makkar: I think with the advent of the TAVR procedure, we realized early on that some of these strokes that occurred in patients were because of the release of material into the brain, or embolization of the material, as it is called. I think that is what set the whole field of research into embolic protection or cerebral protection into motion. So yes, I believe we knew about it in the past, but I think the awareness with the onset of the TAVR procedure brought it to the forefront and has stimulated the research in this field.
END OF INTERVIEW
This information is intended for additional research purposes only. It is not to be used as a prescription or advice from Ivanhoe Broadcast News, Inc. or any medical professional interviewed. Ivanhoe Broadcast News, Inc. assumes no responsibility for the depth or accuracy of physician statements. Procedures or medicines apply to different people and medical factors; always consult your physician on medical matters.
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