Patients who received a transcatheter supra-annular self-expanding heart valve had less structural deterioration in the valve after five years compared with similar patients who received a biologic valve surgically.
This was the headline finding from a pooled analysis of the CoreValve US Pivotal and SURTAVI trials, delivered by Michael J Reardon (Houston Methodist DeBakey Heart and Vascular Center, Houston, USA) during a late-breaking trial session at the American College of Cardiology’s annual scientific sessions (ACC 2022, 2–4 April, Washington DC, USA).
Overall, patients with structural valve deterioration in their artificial valve were about twice as likely to die or need to be rehospitalised as those who did not, according to Reardon.
The study met its primary endpoint—the incidence of structural valve deterioration was significantly lower in patients who received transcatheter aortic valve implantation (TAVI) than in those who received surgical aortic valve replacement (SAVR),
“Heart surgeons tend to worry that in younger, lower-risk patients, replacement valves inserted using TAVI may fail more quickly than surgically inserted valves,” Reardon said. “The results of this study suggest exactly the opposite—that at five years, the TAVI-inserted valve has less structural deterioration than the surgically inserted one.”
The study is the largest to assess structural valve deterioration in patients who participated in randomised trials comparing TAVI and SAVR and the first to show less structural valve deterioration after five years among patients treated with TAVI compared with SAVR, Reardon said.
Bioprosthetic valves are typically made from pig or cow heart tissue, with their main advantage over mechanical valves seen to be that patients do not require lifelong anticoagulants to prevent blood clots. However, structural valve deterioration —which includes problems such as scarring, thickening/calcification, hardening or fracturing of the valve frame—is only an issue with bioprosthetic valves and is the most frequent cause of valve failure.
Bioprosthetic valves have an average lifespan of about 15 years. In older patients whose life expectancy may be limited by age and other health problems, valve durability has been less of a concern, Reardon said. Previous studies suggest, however, that younger patients are at higher risk for structural valve deterioration because their valves fail more quickly and because they have a longer potential life span. Previous studies have not clearly established whether the risk of structural valve deterioration is higher with TAVI or with SAVR.
“Durability of the replacement valve becomes increasingly important in younger patients,” he said.
In the current study, Reardon and his colleagues analysed data from 1,128 patients who underwent TAVI and 971 patients who underwent SAVR in the two large, randomised trials—both of which used the CoreValve and Evolut TAVI systems (Medtronic)—to determine the frequency of structural valve deterioration at five years using Doppler echocardiography. The researchers also examined the factors that predicted deterioration in the same patient cohort plus an additional 2,663 patients who were treated with TAVI in a non-randomised registry of the two trials.
They found that 2.6% of the patients treated with TAVI had structural valve deterioration at five years, compared with 4.4% of those treated with SAVR. Patients in both groups who developed structural valve deterioration were at about 50% greater risk of death or hospitalisation for valve-related disease or heart failure as patients who did not have structural valve deterioration, the researchers said.
“Using Doppler echocardiography alone, we have shown that structural valve deterioration occurred statistically significantly more frequently with SAVR than with TAVI and was associated with a doubling of risk for mortality or rehospitalisation for valve failure,” Reardon said.
The most important predictors for developing structural valve deterioration were being heavy or overweight, younger age, female gender and not having previous coronary interventions or atrial fibrillation (a type of arrhythmia), he added.
The current study is limited to five years of follow-up. Establishing durability of the valves over a longer period of time remains important. Patients in the two ongoing trials, SURTAVI for intermediate risk and Evolut for low risk, will each be followed for 10 years in a bid to answer this question.