Transcatheter Aortic Valve Replacement in Low-Risk Patients at Five Years

The outcomes of the Transcatheter Aortic Valve Replacement in Low-Risk Patients at Five Years (5y PARTNER 3 trial) were presented during the late-breaking clinical trial session of TCT 2023 and simultaneously published in the New England Journal of Medicine. The results give valuable insights and add new evidence for the decision making and treatment of low-risk patients with severe symptomatic AS.

The PARTNER 3 trial randomly assigned 1,000 patients with severe symptomatic aortic stenosis (AS) and low surgical risk (STS-PROM < 4 percent) to undergo either transcatheter aortic valve replacement with a balloon expandable bioprosthesis (503 patients) or surgical aortic valve replacement (497 patients) with a prespecified superiority hypothesis. The two primary endpoints were composite of death, stroke, or rehospitalization, and hierarchical composite of death, disabling stroke, nondisabling stroke, and the number of rehospitalization days.

At five years, there was no significant difference in the risk of death, stroke, or rehospitalizations between the transcatheter aortic valve replacement (TAVR) and surgical aortic valve replacement (SAVR) arms. The Kaplan–Meier estimates were 22.8 percent vs. 27.2 percent in the TAVR and SAVR groups, respectively; p=0.07. Furthermore, Kaplan-Meier curves did not show a statistical difference in the five-year all-cause mortality. At five years, there was a mortality of 10.0 percent vs. 8.2 percent in the TAVR and SAVR groups, respectively; HR 1.23 and 95 percent CI 0.79-1.90. Remarkably, the Kaplan-Meier all-cause mortality curves initially showed an early result favoring TAVR, but beyond one year, attenuation of the observed differences occurred, with the curves crossing close to 36 months. The risk of cardiovascular (HR 1.08; 95 percent CI 0.61–1.92) and noncardiovascular (HR 1.46; 95 percent CI 0.74–2.90) mortality was similar in both groups. Valve hemodynamics were similar in both study arms, with a mean valve gradient 12.8±6.5 mmHg vs. 11.7±5.6 mmHg in the TAVR and SAVR groups, respectively. 

Moreover, bioprosthetic valve failure defined by VARC-3 criteria occurred at similarly low rates in both groups: 3.3 percent vs. 3.8 percent in the TAVR and SAVR groups, respectively. However, TAVR was associated with an increased risk of valve thrombosis: 0.2 percent vs. 2.5 percent; HR 10.52 (95 percent CI 1.37–80.93). Patient-reported health status was similar in the two groups, with a mean Kansas City Cardiomyopathy Questionnaire–Overall Summary score (KCCQ-OS) of 86.2 vs. 85.9 in the TAVR and SAVR groups, respectively. Similarly, 84.4 percent vs. 86.0 percent of the patients in the TAVR and SAVR groups presented with a New York Heart Association (NYHA) class I or II at five years, respectively.