New data from PARTNER 3 shows the procedure reduces one-year mortality in patients with aortic stenosis.
Michael Mack, MD
Findings from the multicenter, randomized PARTNER 3 trial show that patients with severe aortic stenosis with low surgical risk are at a significantly lower risk of death, stroke or rehospitalization at 1 year post-TAVR than those treated with surgical aortic valve replacement. The low-risk patient population was previously poorly evidenced having significant benefit with TAVR.
“Current clinical practice has restricted the use of TAVR in patients who are at low risk and in younger patients, for whom surgery is standard therapy,” investigators, led by Michael Mack, MD, medical director of Cardiovascular Surgery at Baylor Health Care System, wrote. “Previous research that supports the use of TAVR in low-risk patients is limited, mostly consisting of retrospective, observational studies.”
The team compared valve replacement procedures in 1000 patients from 71 medical centers. Mean patient age was 73 years, with a mean Society of Thoracic Surgeons risk score of 1.9% (with greater scores indicating a greater risk of death within 30 days post-procedure). Patients were randomly assigned to either TAVR with transfemoral balloon-expandable valve placement or surgery.
Primary patient endpoint was a composite of death, stroke, or rehospitalization at 1 year, as per the Kaplan-Meier estimate. Investigators conducted both noninferiority and superiority testing in the as-treated patients.
At 1 year, the estimated rate of primary composite endpoint was significantly lower in the TAVR group (8.5%) than in the surgery group (15.1% [95% CI: -10.81 to -2.5; P< .001 for noninferiority; 95% CI: .37 - .79; P= .001 for superiority]). At 30 days post-care, TAVR patients reported a lower rate of strokes than those who underwent surgery (P= .02), as well as new-onset atrial fibrillation (P< .001), and death (P= .01).
Investigators found no significant differences in major vascular complications between treatment groups, nor any differences for permanent pacemaker insertions, nor moderate/severe paravalvular regurgitation.
Additionally, TAVR-treated patients reported more rapid improvements in a series of metrics including the New York Heart Association (NYHA) functional class ranking, six-minute walk-test distance, and the Kansas City Cardiomyopathy Questionnaire (KCCQ) overall summary score. That said, all data was limited to one-year outcomes—and future studies should emphasize greater lengths of time post-care.
“Definitive conclusions regarding the advantages and disadvantages of TAVR as compared with surgery (with either bioprosthetic or mechanical valves) depend on long-term follow-up,” Mack and colleagues wrote. “In this trial involving younger, low-risk patients, the protocol requires clinical and echocardiographic follow-up to continue for at least 10 years.”
In an interview with MD Magazine® while at the American College of Cardiology (ACC) 2019 Annual Scientific Sessions in New Orleans, LA, investigator Michael J. Reardon, MD, professor of Cardiothoracic Surgery and Allison Chair of Cardiovascular Research at Houston Methodist Hospital, explained that low-risk patients make up about 80% of the aortic stenosis population. Findings that support the benefits of TAVR in this population may be incremental in overall benefit, but “seismic” in shifting patient treatment options.
“This data tells us that TAVR is probably the preferred therapy in the group of patients we tested,” Reardon said about PARTNER. “And when I talk to patients in my office now, when they come in with aortic stenosis and they're a candidate for a biologic surgical valve because of age and other criteria—if I don't talk to them about TAVR, I have not given them really true informed consent, and we're not doing true shared decision-making.”
The study, "Transcatheter Aortic-Valve Replacement with a Self-Expanding Valve in Low-Risk Patients," was published online in New England Journal of Medicine.