Percutaneous transcatheter aortic valve implantation: assessing results, judging outcomes, and planning trials: the interventionalist perspective.

Aortic valve stenosis is increasing in frequency as the population ages. Surgical aortic valve replacement is the gold standard for symptomatic patients with severe aortic valve stenosis. However, in a subset of high-risk patients, the surgical option is excluded due to severe comorbidities. Recently, an alternative to surgical aortic valve replacement--percutaneous aortic valve replacement (PAVR)--has emerged. Since the first PAVR in a human in 2002, the percutaneous heart valves (PHVs) have already undergone several modifications from first generation devices. Currently, there are 2 PHVs in clinical application, a balloon-expandable and a self-expandable PHV, with several others achieving first-in-man application. With the extremely rapid technological advancements, PAVR is probably here to stay. The next steps required would be to formulate goals to assess results and outcomes of PAVR, and plan trials to test their clinical applicability. This article discusses how best to assess results and outcomes, which may require a paradigm shift in mindset. Apart from the randomized controlled trial, some of the more novel concepts in trial design, which may be more suitable in this area, are also explored.