CardioNerds: The proliferation of transcatheter aortic valve replacement (TAVR) has revolutionized the care of patients with aortic stenosis across the spectrum of surgical risk with strong data for both balloon expandable valves (BEVs) and self-expanding valves (SEVs) compared with surgical AVR. Dr. Puri, what is your balance of BEV vs SEV use and how do you decide which to use for a given patient?
Dr. Rishi Puri: It’s important to adopt a “horses for courses” (the right valve for the right patient) approach for valve choice and implant technique/strategy. This is to optimize lifetime management decisions for patients that are residual life expectancy, anatomy and valve durability-dependent. As a result, my TAVI practice is typically a 50:50 split across the 2 main commercially available balloon and self-expanding THV systems here in the US. SAVR will continue to remain very important, especially for young patients in their 60s, and in those with anatomy where TAVI is likely to be anatomically challenging with suboptimal results.
You are among few TAVR operators who have had the opportunity to use the latest iteration of Medtronic’s SEV platform – the Evolut™ FX TAVR system – as part of a limited market release program. What are the most clinically relevant design innovations of the FX system and what issues are these intended to address?
Dr. Rishi Puri: The Evolut FX system is largely the same THV platform as the Pro+ platform, except there are small radio-opaque markers at 3 mm above the inflow to mark the 3 commissural tabs, which helps one understand commissural alignment. The delivery system has been re-engineered to have 1 less spine, enabling greater catheter flexibility in all directions. This has made the Evolut FX system easier to push across more challenging aortic anatomies (tortuosity, horizontal aortas). These changes have also allowed THV annular engagement to be more co-axial, which leads to more stable deployment. I also think that PVL is less in the context of greater coaxility.
Having just begun my structural training at the Cleveland Clinic, I have been fortunate to get my hands on the FX system and in fact have never personally used its predecessor, the Evolut PRO+. In your experience, how does the FX system compare with the PRO+?
Dr. Rishi Puri: It is noticeably easier to push in the ilio-femoral vessels and aorta, easier to push in horizontal aortic anatomies, it’s more stable during deployment, and easier to appreciate parallax and commissural alignment.
Iterative innovation to improve patient outcomes is one of the most exciting aspects of structural intervention. In your opinion, what drawbacks remain with current platforms and what future design changes would you like to see in the next generation of TAVR valves?
Dr. Rishi Puri: Most, if not all current THV platforms have iterative changes being tested. There is no ‘perfect” THV currently and likely there never will be. This is the reason why one must gain solid experience with at least 2-3 different THV systems to pick and choose the right valve for the right patient. There are caveats to each general design, and changes to one aspect can have consequences for another aspect of the TAVI procedure, so it’s a difficult question to answer succinctly. That being said, the ability to achieve coronary alignment in an easy, straightforward fashion will always be important. Valve durability and leaflet thrombosis remains an issue and I believe the 2 are mechanistically tied, so advancements in polymeric leaflets, their anti-thrombogenicity and anti-calcification properties will be important. A very large gap remains in how we deal with annular/LVOT calcification in order to safely and effectively seal the annulus.
About Rishi Puri:
Rishi Puri, MBBS, PhD, FRACP, is a coronary and structural interventional cardiologist at the Cleveland Clinic. He is also an Associate Professor of Medicine and Medical Director of the angiography and IVUS Core Laboratory. He completed his clinical and academic training in Adelaide (Sth Australia), Cleveland (USA), Quebec City (Canada), Rennes (France), and Zurich (Switzerland). Dr. Puri has published avidly with over 330 original manuscripts in high-impact journals across a broad topic base including transcatheter structural heart interventions for valvular heart disease and heart failure, atherosclerosis progression-regression and plaque imaging, and coronary physiology/pharmacology. He is actively involved in developing novel device technologies in the coronary, structural heart disease and interventional heart failure spaces, and advises a range of medical start-up companies. He currently serves as global co-PI for the TRICAV pivotal trial testing a bi-caval stenting system for patients with severe TR, the ADVANCE-DCB FIM trial of a dual API nanoparticle drug-eluting balloon in de novo coronary lesions, and is on the global steering committee of the pivotal EXPAND TAVR trial evaluating TAVR in moderate aortic stenosis.