Durability of devices: long-term results and clinical outcomes

Over the last decade, transcatheter aortic valve implantation (TAVI) has emerged to become the treatment of choice for inoperable patients and the preferred alternative for high-risk patients with severe, symptomatic aortic stenosis (AS). Questions about the long-term durability of TAVI valves were raised early in the history of the procedure. Although there has not yet been a significant signal of early structural valve deterioration (SVD), these concerns remain important today, especially if TAVI is to be considered for use in lower-risk and younger patients with longer life expectancy. Durability expectations for TAVI to some degree parallel those of surgical bioprostheses, but the different tissue, mounting design and crimping of TAVI devices might adversely influence long-term results. The experience with surgical bioprostheses has shown that deterioration of these valves is a slow and gradual process. Thus, despite promising midterm results of many surgical bioprostheses at five to seven years, design faults with higher failure rates have become manifest eight to 10 years after implantation. Similarly, although the initial five-year outcomes of TAVI are promising, these results cannot yet be extrapolated to predict long-term durability with any firm degree of assuredness, especially in younger patient populations. Thus, a high degree of caution is necessary when considering TAVI in intermediate-risk and younger patients until more evidence of durability equivalent to that of surgical bioprostheses is forthcoming.