Primary-outcome gap shrinks after first year; increased valve thrombosis noted in TAVR arm between years 1 and 2
Patients at low surgical risk for mortality who underwent transcatheter aortic valve replacement (TAVR) with a balloon-expandable valve continued to show significantly better outcomes at 2 years than those who underwent surgical aortic valve replacement (SAVR), but the differences between the two groups began to narrow from year 1 to year 2, according to late-breaking trial results presented Sunday at the American College of Cardiology (ACC) Scientific Sessions 2020 virtual conference.
Michael J. Mack, MD, a cardiothoracic surgeon at Baylor Scott & White Health, Dallas, presented the 2-year results of the PARTNER 3 trial, which randomized low-risk patients with severe, symptomatic aortic stenosis to undergo TAVR with the balloon-expandable Sapien 3 transcatheter heart valve (Edwards Lifesciences) or SAVR.
The PARTNER 3 trial at 1 year showed superiority of TAVR over SAVR for the primary composite outcome of death, stroke or rehospitalization. That outcome occurred in 8.5% of TAVR patients and 15.1% of SAVR patients, according to results presented at ACC 2019 and published in The New England Journal of Medicine.
At 2 years, the difference in the composite rate remained statistically significant but narrowed between TAVR (11.5%) and SAVR (17.4%), mostly due to an increase in late events in the TAVR arm, including more late deaths and stroke, between years 1 and 2. There was also an increase in valve thrombosis in the TAVR group at 2 years. The improvement in hemodynamics and the frequency of moderate or mild paravalvular regurgitation were unchanged between 1 and 2 years in both TAVR and SAVR patients.
Mack concluded that there was a 37% relative reduction in death, stroke and rehospitalization in the TAVR arm but that there were more death and stroke events in TAVR patients from 1 to 2 years and there were reduced cardiovascular-related hospitalizations in favor of TAVR.
The relevance of valve thrombosis on long-term outcomes, particularly structural valve deterioration, needs longer term follow-up, but there are no early signals of poor outcomes, and the risks and benefits of anticoagulation need to be assessed on a patient-to-patient basis, Mack said.
“Longer-term outcomes are particularly important for this patient population because younger, low-risk patients have longer to live with this valve than patients that have been previously studied,” Mack said in a news release accompanying the study results. “Therefore, the durability of the valve is of utmost importance.”
The PARTNER 3 trial was funded by Edwards Lifesciences.