Erik W Holy (Heart Center, Segeberger Kliniken, Bad Segeberg, Germany) and others report in EuroIntervention that the CoreValve self-expanding transcatheter aortic valve implantation (TAVI) device is associated with a “favourable performance” at long-term follow-up (8.9 years). However, the authors claim this finding does not provide any conclusions about the durability of TAVI valves but rather “contributes to the growing evidence” for valve durability.
The current data for transcatheter heart valve durability are limited by five-year follow-up but, according to Holy et al, this has implications for expanding the use of TAVI beyond inoperable and high-risk patients. They write: “While a durability of at least five years, as suggested by previous studies, is acceptable for an elderly high-risk population, evidence of long-term durability is mandatory before replacing surgery with TAVI in younger, lower-risk populations [i.e. because they are likely to have a longer life expectancy].”
To further assess the durability of TAVI devices beyond five years, the authors reviewed data from the long-term structured follow-up programme of CoreValve using standardised definitions and core lab adjudication of valve performance. The primary endpoints were the rate of bioprosthetic valve failure and transcatheter heart valve long-term performance. “Late bioprosthetic valve failure was defined according to the recently proposed consensus definition, including one of the following criteria occurring >30 days after TAVI: severe haemodynamic structural valve deterioration, evidenced by a transprosthetic mean pressure gradient ≥40mmHg and/or 20mmHg rise from baseline or severe transvalvular aortic regurgitation; and bioprosthetic valve dysfunction leading to death or reintervention,” Holy et al explain.
Of 152 patients in the programme, follow-up data were available for 60 patients who were alive for more than five years after the initial procedure (of 68 in total). During the total clinical follow-up period of 8.9 years, no severe structural valve deterioration or death attributable to valve failure was reported. Furthermore, the estimated rate of bioprosthetic valve failure at both seven and eight years was 7.9% for the actuarial and for 4.5% for the actual analysis.
According to the authors, paravalvular regurgitation severity tended to change over time in a significantly proportion of patients—regressing from moderate to less than mild in five patients, remains stable in 48% of patients, increasing by more than one grade in 32% of patients and improvingd by more than one grade in 20% of patients.
The authors comment: “The present data provides a good reason to believe that structural valve deterioration of self-expanding valves beyond five years and up to eight years remains rare.” They add that their study documents “favourable performance of the self-expanding CoreValve with low rates of bioprosthetic valve failure”. “The present study cannot conclude—but rather contributed to the growing evidence—upon transcatheter heart valve durability,” Holy et al surmise and note that “further large-scale studies and registries are required to confirm the non-inferiority of transcatheter heart valves compared to surgical bioprosthesis in terms of long-term durability.”