Pushing the Limits in Transcatheter Aortic Valve Replacement: High-Volume Center's Effect, Overconfidence, or Something Else?

The recent literature on transcatheter aortic valve replacement (TAVR) is shedding new light on the perspective to extend this procedure to other lower risk-category of patients, leading in fact to a potential erosion of the current guidelines. Notwithstanding the warnings provided in the literature regarding the risk of severely impairing complications, unclear survival advantage, and cost-inefficiency, many observational studies, especially performed in high-volume centers, support a general drive toward the recruitment of intermediate-low risk patients in the expectation of clinical advantages versus standard surgical replacement. It appears that, in combination with the development of more refined technologies, medical groups with matured experience and centers able to successfully manage patients with different profiles have been progressively "selected" and emerged pushing further the limits of the procedure itself. On the surgeon side, involved in the surgical assistance of TAVR procedures or in the standby-coverage in case of major complications, the expansion of indications and the interventionists' overconfidence have relevant implications. Considerations on the actual long-term effectiveness of the procedure on younger lower-risk patients in terms of actual hemodynamic durability and inability to deal with functional and morphological aspects of annular calcifications should be made. Also, it seems that other technologies enabling annulus decalcification, such as sutureless valve, have been totally overlooked and trials sponsored by industrial leaders in the market have taken the lead. Such a rapid expansion of TAVR indications should be better understood considering that in the surgical field valve bioprostheses needed to undergo a much longer validation period and the appearance of data on their 20 years follow-up after implantation was required before the application in younger patients.