Future of TAVR Devices

Stanton Rowe

It has been nearly 20 years since that eventful first case by Professor Cribier. I sat nervously at home beside the telephone waiting for the call, as flying there might have delayed the case to the demise of the patient, who was so critically ill. No such angst occurs today with transcatheter aortic valve replacement (TAVR); it is almost always a less than 1-hour predictable procedure with predictable outcomes and there is growing consensus about the procedure and its application (1). That being said, it remains imperfect.

The future of TAVR will focus on two fronts: expanded indications discussed in the clinical review and improved implants and accessories. The latter will focus on reduced profiles, although 12-F may be close to a threshold with material science limitations. There have been attempts at and patents regarding staged implants to further reduce profile (think stent, add leaflets second), but these typically add complexity, and complexity inevitably leads to variable outcomes.

Accessories will focus on large bore closure to reduce femoral artery complications, one of the more common patient complaints. Stroke prevention is another focus, although first-generation devices for embolic protection do not clearly improve clinical stroke and add complexity and cost in the process. Some accessories focus on alternative access for the few patients who cannot be accessed via a femoral route. Other improvements in rapid pacing systems, guidewires, and balloons incrementally improve and possibly simplify the TAVR procedure.

While durability remains a focus, especially in younger patients, there are early research projects focused on a variety of advanced materials for leaflets with the objective of forming biologically similar valves. Using the human body as a bioreactor by introducing an extracellular matrix for cellular infiltration and differentiation is a laudable goal, especially for the few younger patients in whom durability is a multi-decade issue. These developments are also applicable for the same reasons in the pulmonic replacement application.

The refinement of balloon-expandable and self-expanding platforms for TAVR have made a large impact on outcomes combined with clinical experience, improved imaging, and procedural refinements. We can expect that such incremental improvements to continue and provide further benefits in reducing variation and complexity. Delivery system improvements in expandable sheaths, steerable systems, precision controls and ergonomics will continue to refine this procedure.

Expanded indications will lead us to new patient populations where safety and predictability will be paramount, especially the low-risk population. TAVR will continue to be refined for many decades and replace a portion of surgical patients; however, the vast majority of growth in TAVR will remain the untreated severe AS patents.

From preclinical development to sophisticated randomized trials, the TAVR journey has been more complicated than many recall, but the perseverance of many clinical leaders and companies has resulted in an important contribution to the treatment of aortic stenosis. Today the regulatory challenges are well known and predictable, while the reimbursement landscape, especially in international markets, is much more complicated. The patent landscape has matured and some of the early fundamental patents are expiring, but there remains a formidable patent landscape to understand as new devices are considered.

As patient-centric outcomes measures become more refined, these findings will drive more patient-centric improvements into the TAVR procedure. As TAVR matures, improving the outcomes that matter the most to patients will not only drive patient acceptance but also referral to centers focused on these outcomes.

Undoubtedly, the exposure of new TAVR systems, accessory equipment, procedural simplification, and expanding indications will fuel the anticipated growth of TAVR over the next decade. This is clearly an example of translational science at its best. Wherein initially TAVR was developed to manage an extreme clinical need in patients who were not candidates for surgery, we can now envision technology iterations to address very different and multivaried patient populations.