Low-Risk TAVR Sustains Benefits at 2 Years in PARTNER 3

Transcatheter aortic valve replacement (TAVR) procedure is associated with 37% reduction in death, stroke, or cardiovascular rehospitalization in low-risk patients with aortic stenosis when compared to surgery, according to new PARTNER 3 findings.

The trial data, presented virtually at the ACC.20 Together with Word Congress of Cardiology (ACC/WCC) Scientific Sessions this weekend, showed significant TAVR benefit for 30-day outcomes and sustained efficacy versus surgery over 2 years post-practice.

Investigators, led by Michael J. Mack, MD, cardiothoracic surgeon at Baylor Scott and White, sought to complement previous PARTNER trial success observed in older, higher-risk patients with aortic stenosis with an understanding of its sustained benefit in younger patients with lesser surgery risk.

Data reported by the PARTNER 3 investigators last year showed TAVR’s benefit compared with surgery at 1 year. Mack and colleagues now hoped to expand their understanding of the practice’s benefit and sustained efficacy.

The one-year outcomes were only the first look at how these patients do, and this is the second look,” Mack said in a statement. “On the basis of one-year data, many physicians were counseling patients that TAVR outcomes were better than surgery. Now, we see that the outcomes are roughly the same at 2 years.”

The trial included 1000 patients with severe aortic stenosis and a risk score of >4% based on Society of Thoracic Surgeons scoring. Patients were randomly split 1:1 to undergo either TAVR with the SAPIEN 3 valve device, or surgery.

Mean patient age was 73 years old, with both groups reporting a majority of males (67.5% for TAVR; 71.1% for surgery), and a BMI score >30 (30.7±5.5; 30.3±5.1, respectively). More than 30% of the observed patient population also had diabetes; another 16% of patients suffered from atrial fibrillation.

Mack and colleagues assessed for a primary endpoint of noninferior composite patient death, stroke, or rehospitalization due to cardiovascular problems.

At 2 years, 11.5% of patients to have undergone TAVR reached the composite endpoint, versus 17.4% of those to undergo surgery—indicating noninferiority.

In secondary analyses assessing rates of death and stroke between the treatment groups, investigators observed insignificant differences between patients who received TAVR versus surgery: deaths occurred in 2.4% and 3.2%, and stroke occurred in 2.4% and 3.6%, respectively.

Notably fewer patients to receive TAVR were rehospitalized over 2 years (8.5%) versus those to receive surgery (12.5%).

Though valve thrombosis was significantly greater in TAVR-treated patients (2.7%) than surgery patients (0.7%), investigators reported no significant deterioration in valve functioning between years 1 and 2 in either study group.

Limitations included that the observed patients were those with severe, symptomatic aortic stenosis and a tricuspid valve. Additionally, the follow-up rate among those who underwent surgery was limited compared to that of the TAVR follow-up population.

Investigators intend to track patient outcomes over the span of a decade, with Mack stressing that replaced valve durability is absolutely critical among the low-risk patient population.

“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,” he said.

Approximately 4 in every 5 US patients in need of valve replacement for severe aortic stenosis fall into the observed low-risk patient category observed in PARTNER 3. As lesser invasive procedures including TAVR continue to rise in popularity among patients, clinicians are working to fully understand its benefits and tolerability over time compared to standard surgery.

The study, "Two-Year Clinical and Echocardiographic Outcomes From The PARTNER 3 Low-Risk Randomized Trial," was published online in The New England Journal of Medicine.