medwireNews: The type of aortic value implanted during transcatheter aortic valve replacement (TAVR) for severe symptomatic stenosis in women with small annuli may matter, according to the results of a secondary analysis of a randomized controlled trial.
While clinical outcomes at 12 months of follow-up were found to be similar among women who had a self-expanding valve (SEV) or balloon-expandable valve (BEV) implanted, there were some significant differences seen in the new valves’ function, report researchers.
Specifically, there was a significant and “markedly reduced” incidence of bioprosthetic valve dysfunction (BVD) with SEV than with BEV, at 8.4% versus 41.8%, say Roxana Mehran (Icahn School of Medicine at Mount Sinai, New York, USA) and fellow SMART study investigators in JAMA Cardiology.
BVD was defined based on both structural and non-structural parameters including a mean aortic valve gradient of at least 20 mmHg, prosthesis–patient mismatch (PPM), moderate or greater aortic regurgitation seen on echocardiography, valve thrombosis, endocarditis, and the need for a repeated aortic valve intervention.
SMART was a large-scale trial conducted in 83 centers in North America, Europe, and Israel between 2021 and 2022. It was designed to compare the use of SEV and BEV in people with aortic stenosis and a small aortic annulus. The trial included 716 individuals, of whom just 95 were men. With the majority of trial participants being women, a prespecified secondary analysis of the outcomes seen in women specifically was included in the trial’s design.
Of the 621 women who were included in the study, 312 had been randomly allocated to undergo TAVR with a SEV and 309 with a BEV. Baseline characteristics were similar among the two groups of women. The mean age was 80.2 years in the SEV group and 80.1 years in the BEV group. The mean aortic annulus area was a respective 378.3 mm2 and 379.1 mm2 in the groups and the surgical risk, as determined by the Society of Thoracic Surgeons Predicted Risk of Morality score, was 3.4% when considering both groups of women together.
Alongside BVD, the coprimary clinical endpoint for the study was a composite of all-cause mortality, disabling stroke, or heart failure rehospitalization occurring over the course of 12 months. This occurred in a comparable 9.4% and 11.8% of women in the SEV and BEV groups, respectively. The respective rates for each component of this endpoint – death (5.2 vs 6.2%), disabling stroke (2.9 vs 3.0%), and heart failure rehospitalization (4.0 vs 4.1%) – were also similar between the groups.
In terms of the new valves’ function, “SEV implantation resulted in lower aortic valve gradients and larger effective orifice areas at 30 days and 12 months and less mild or greater aortic regurgitation at 12 months compared to BEV implantation,” the SMART investigators report.
Additionally, moderate or severe PPM, which is “a mismatch between the effective orifice area of a prosthetic valve and the patient’s cardiac output requirements in relation to body size,” and generally “associated with worse clinical outcomes,” occurred in significantly fewer women implanted with SEV than BEV at both 1 month (9.2 vs 34.1%) and 12 months (11.2 vs 37.4%) of follow-up. PPM was defined according to Valve Academic Research Consortium (VARC)-3 criteria.
“SMART stands as the first powered randomized clinical trial to demonstrate superior hemodynamic performance of SEVs compared to BEVs, specifically in women with small aortic annuli,” the investigators say.
Mehran et al also acknowledge that further follow-up is needed, which they plan to do for up to 5 years, and that the results are only applicable to women with severe aortic stenosis with small annuli undergoing TAVI with the specific valves tested. The findings “should not be generalized to other TAVR platforms or conditions,” they say.
“[T]his trial sets the stage for expectations that an SEV might improve long-term clinical outcomes in women with severe aortic stenosis and small annuli undergoing TAVR,” the authors conclude.
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