Five-year results suggest that surgical aortic valve replacement (SAVR) is associated with lower rates of mortality and major adverse cardiac and cerebrovascular events (MACCE) than transfemoral transcatheter aortic valve replacement (TAVI) performed using first-generation devices in low- and intermediate-risk patients with severe aortic stenosis.
The findings from the OBSERVANT study (Observational Study of Effectiveness of SAVR–TAVI Procedures for Severe Aortic Stenosis Treatment) were published in Circulation: Cardiovascular Interventions. Marco Barbanti (University of Catania, Catania, Italy) et al say that the data need to be confirmed in further randomised trials using new-generation TAVI devices.
Between December 2010 and June 2012, investigators enrolled an unadjusted population of 7,618—of these, 5,707 patients had SAVR and 1,911 patients underwent TAVR. Two groups with similar baseline characteristics were selected by propensity score matching, and all outcomes were adjudicated through linkage with administrative databases.
Primary endpoints were death from any cause and major adverse cardiac and cerebrovascular events (MACCE) at five years. There were 1,300 patients in the matched population—650 in each group. The propensity score method generated a low and intermediate-risk population (mean logistic EuroSCORE 2: 5.1±6.2% vs. 4.9±5.1%, SAVR versus transfemoral TAVI, p=0.485).
Brabanti et al found that, at five years, the rate of death from any cause was 35.8% in the surgical group and 48.3% in the transcatheter group (hazard ratio [HR] 1.38, 95% confidence interval [CI] 1.12–1.69, p=0.002). TAVI was also associated with an increased risk of major adverse cardiac and cerebrovascular events compared to SAVR (42.5% vs. 54%, HR 1.35, 95% CI 1.11–1.63, p=0.003). The cumulative incidence of cerebrovascular events, myocardial infarction, and coronary revascularisation were similar in the study groups at five years.
Brabanti told Cardiovascular News that there were several reasons that could account for the “provocative results” obtained. He explained: “The inclusion of an unselected population—including patients with unfavourable anatomical and clinical features for TAVI—likely led to a higher incidence of postprocedural sequalae (paravalvular leak, pacemaker implantation) and unsolved cardiac pathologies—above all, incomplete coronary revascularisation and untreated degenerative mitral and functional tricuspid regurgitation—that could have had a significant impact on the long-term prognosis of the TAVI patients. And, lower haemoglobin and albumin values, and a higher rate of oxygen dependency among TAVI patients compared with SAVR patients, which persisted despite the propensity adjustment, imply a sicker TAVI group at baseline. In addition, the study enrolled patients during the early months of TAVI adoption in many centres. A learning curve was likely present, which might have affected TAVI outcomes early in the study.”
One-year data from OBSERVANT showed that mortality is similar for transfemoral TAVI and SAVR in a real-world propensity-matched population with aortic stenosis and at low and intermediate risk. The authors advise that the latest findings need further validation in randomised controlled trials that use new-generation TAVI devices in a real-world population.