Transcatheter Aortic Valve Replacement Noninferior to Surgery in Intermediate Risk Patients

Transcatheter aortic valve replacement (TAVR) was noninferior to surgical aortic valve replacement (SAVR) among intermediate-risk patients with aortic stenosis, according to results from the PARTNER 2 (Placement of Aortic Transcather Valves) trial presented at the 2016 American College of Cardiology Scientific Sessions & Expo (ACC) in Chicago and simultaneously published in the New England Journal of Medicine.

Craig R. Smith, MD, surgeon-in-chief at New York Presbyterian Hospital and Columbia University Medical Center, presented the findings on behalf of PARTNER 2 investigators.

At an ACC press conference, Dr Smith stated that the previous PARTNER 1 trial confirmed that TAVR was “superior to standard therapy for patients with severe aortic stenosis who were not candidates for surgery and equivalent to surgery in high-risk patients.” However, second generation TAVR systems have been associated with improved clinical outcomes, which suggests that TAVR therapy could be effectively extended to lower-risk patients.

In PARTNER 2, a total of 2032 intermediate-risk patients were included from 52 sites in the United States and 2 sites in Canada. Intermediate risk was determined by a risk model designed by the Society of Thoracic Surgeons (STS) that estimates risk of death 30 days after surgery.  Patients with an STS score of ≥4% were considered for the study.

Patients who were eligible for transfemoral access were randomly assigned on a 1:1 ratio to receive transfemoral TAVR (n=775) or SAVR (n=775). Patients who were ineligible for transfemoral access were randomly assigned to receive transpical/transaortic TAVR (n=236) or SAVR (n=246).

The primary end point of the study was all-cause mortality or disabling stroke after 2 years. At the 2-year follow-up, Dr Smith and his colleagues observed that the primary end point rates were similar in the TAVR and surgical intervention groups (P=.001 for noninferiority).

The rate of all-cause mortality or disabling stroke was 19.3% in the TAVR group and 21.1% in the SAVR  group (hazard ratio [HR]: 0.89; 95% confidence interval [CI]: 0.73-1.09; P=.25).

Patients who underwent transfemoral-access TAVR had lower rates of mortality or disabling stroke than transfemoral surgery (20.4% vs 16.8%; HR: 0.79; 95% CI: 0.62-1.00; P=.05). However, in patients who received transthoracic-access aortic valve replacement, the rates were very similar.

Dr Smith stated that patients who underwent TAVR had larger aortic-valve areas and reduced rates of acute kidney injury, severe bleeding, and atrial fibrillation after 2 years. SAVR resulted in fewer major vascular complications and less paravalvular aortic regurgitation, as is typically the case.

Although the patients in this study were part of a lower risk category than cohorts of previous trials, these intermediate-risk patients belong to the highest-risk quintile of patients with aortic stenosis eligible for surgery in the United States.

“TAVR is a very reasonable alternative to surgery in intermediate-risk patients,” Dr Smith concluded. He noted that the long-term durability of bioprosthetic transcatheter valves is uncertain, and further research should be conducted to include longer-term follow-up.

References

1. Leon MB, Smith CR, Mack MJ, et al; for the PARTNER 2 Investigators. Transcatheter or Surgical Aortic-Valve Replacement in Intermediate-Risk Patients. N Eng J Med. 2016; doi: 10.1056/NEJMoa1514616.
2. Smith CR. Transcatheter aortic valve replacement compared with surgery in intermediate risk patients with aortic stenosis: final results from the randomized placement of aortic transcatheter valves 2 study. Presented at the 65^th Annual Scientific Session and Expo of the American College of Cardiology. April 2-4, 2016; Chicago, IL.