Cardio nerds: The proliferation of transcatheter aortic valve replacement (TAVR) has revolutionized the care of patients with aortic stenosis across the surgical risk spectrum, with strong data for both balloon-expandable valves (BEVs) and self-expanding valves (SEVs) versus surgical AVRs. dr Puri, what is your balance between using BEV and SEV and how do you decide which one to use for a particular patient?
dr Rishipuri: It is important to use a “horses for courses” approach (the right valve for the right patient) in valve selection and implantation technique/strategy. This is to optimize lifetime management decisions for patients dependent on remaining life expectancy, anatomy and valve longevity. As a result, my TAVI practice is typically split 50/50 between the two main commercially available balloon and self-expanding THV systems here in the US. SAVR will continue to be very important, especially for young patients in their 60’s and in patients with anatomy where TAVI is likely to be anatomically challenging and provide suboptimal results.
They are among the few TAVR users 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 launch program. What are the most clinically relevant design innovations of the FX System and what issues are they intended to address?
dr Rishipuri: The Evolute FX system is largely the same THV platform as the Pro+ platform, except there are small radiopaque markers 3mm above the inflow to mark the 3 commissure tabs, making it easier to understand commissure alignment. The delivery system has been redesigned to have 1 less wedge, allowing for greater flexibility of the catheter in all directions. This makes it easier to slide the Evolut FX system over more challenging aortic anatomies (toroidal, horizontal aortas). These changes have also allowed the THV annular engagement to be more coaxial, resulting in a more stable deployment. I also think PVL is less related to greater coax.
Having just started my structural training at the Cleveland Clinic, I was fortunate enough to get my hands on the FX system, and in fact I never personally used its predecessor, the Evolut PRO+. In your experience, how does the FX system compare to the PRO+?
dr Rishipuri: It is noticeably easier to insert the iliofemoral vessels and aorta, it is easier to insert horizontal aortic anatomy, it is more stable during deployment, and it is easier to assess parallax and commissural alignment.
Iterative innovation to improve patient outcomes is one of the most exciting aspects of structural intervention. What disadvantages do you think remain with current platforms and what future design changes would you like to see in the next generation of TAVR valves?
dr Rishipuri: Iterative changes are tested on most, if not all, current THV platforms. There is currently no “perfect” THV and probably never will be. Because of this, one needs to have solid experience with at least 2-3 different THV systems to select the right valve for the right patient. There are caveats to any general design, and changes to one aspect may have consequences for another aspect of the TAVI process, so it is difficult to give a succinct answer to this question. However, the ability to achieve coronary alignment in a simple and straightforward manner will always be important. Valve durability and leaflet thrombosis remain an issue and I believe the two are mechanistically linked such that advances in polymeric leaflets, their antithrombogenicity and anticalcification properties will be important. There remains a very large gap in managing annular/LVOT calcification to safely and effectively seal the annulus.
About Rishi Puri:
Rishi Puri, MBBS, PhD, FRACP, is a Coronary and Structural Intervention Cardiologist at the Cleveland Clinic. He is also Associate Professor of Medicine and Medical Director of the Angiography and IVUS Core Laboratory. He completed his clinical and academic training in Adelaide (South Australia), Cleveland (USA), Quebec City (Canada), Rennes (France) and Zurich (Switzerland). dr Puri has avidly published over 330 original manuscripts in influential journals on a wide range of subjects including transcatheter structural cardiac interventions in valvular disease and heart failure, progression-regression in atherosclerosis and plaque imaging, and coronary physiology/pharmacology. He is actively involved in the development of novel device technologies in the areas of coronary artery disease, structural heart disease and interventional heart failure and advises a number of medical start-up companies. He is currently serving as Global Co-PI for the pivotal TRICAV study evaluating a bicaval stent system for patients with severe TR, the ADVANCE-DCB-FIM study using a dual API nanoparticle drug-eluting balloon in de- novo coronary lesions, and is in office the global steering committee of the pivotal EXPAND TAVR study evaluating TAVR in moderate aortic stenosis.