PARTNER 3: TAVR Success in Low-Risk Patients

March 16, 2019

NEW ORLEANS — Transcatheter aortic valve replacement (TAVR) using the SAPIEN 3 system (Edwards Lifesciences) showed a significantly lower rate of the primary endpoint, a composite of death, stroke, and rehospitalization at 1 year, compared with surgical valve replacement in patients with severe aortic stenosis at low surgical risk in the PARTNER 3 study.

The study is to be presented Sunday March 17 here at the American College of Cardiology 68th Annual Scientific Session (ACC) 2019 by Martin Leon, MD, Columbia University Medical Center, New York, and simultaneously published in The New England Journal of Medicine (NEJM). Because of an embargo break, the information has been allowed be reported early.

The authors of the NEJM paper note that TAVR has been shown superior or noninferior to surgery in patients with severe aortic stenosis at high or intermediate surgical risk, and more patients now undergo TAVR than isolated surgery for aortic valve replacement in the United States. However, most patients are at low surgical risk, and until now there has been insufficient evidence regarding the comparison of TAVR with surgery in this low-risk group.

"The proof of concept first case of TAVR performed by Cribier and colleagues in 2002 was intended to open a treatment pathway for the highest-risk patients with limited therapeutic options," the authors conclude. "Our findings in low-risk patients suggest that the value of TAVR compared with surgery may be independent of risk profiles."  

The PARTNER 3 trial randomly assigned 1000 patients with severe aortic stenosis and low surgical risk to undergo either TAVR with transfemoral placement of a balloon-expandable valve (SAPIEN 3) or surgery. 

The mean age was 73 years.  The mean Society of Thoracic Surgeons risk score was 1.9% (with scores ranging from 0 to 100% and higher scores indicating a greater risk for death within 30 days after surgery).

The primary endpoint — a composite of death from any cause, stroke, or rehospitalization at 1 year — occurred in 8.5% of the TAVR group vs 15.1% of the surgical group, fulfilling the requirements for both noninferiority (P < .001) and superiority (P = .001) of TAVR.

Table. PARTNER 3: Major Results at 1 Year

Endpoint TAVR (%) Surgery (%) Hazard Ratio (95% CI)
All-cause death/stroke/rehospitalization 8.5 15.1 0.54 (0.37 - 0.79)
All-cause death 1.0 2.5 0.41 (0.14 - 1.17)
Stroke 1.2 3.1 0.38 (0.15 - 1.00)
Rehospitalization 7.3 11.0 0.65 (0.42 - 1.00)
Death or disabling stroke 1.0 2.9 0.34 (0.12 - 0.97)

 

The 30-day results showed lower rates of stroke (0.6% vs 2.4%; P = .02), stroke/death (1.0% vs 3.35; P = .01), and new-onset atrial fibrillation (5.0% vs 39.5%; P < .001) with TAVR.

TAVR also resulted in a shorter index hospitalization than surgery (3 days vs 7 days).   

Patients undergoing TAVR also had more rapid improvements in New York Heart Association class, 6-minute walk test distance, and Kansas City Cardiomyopathy Questionnaire (quality of life) score than those who underwent surgery.

Complications that had been more frequent with TAVR than with surgery in previous trials occurred with a similar frequency in the two groups in this trial. These included major vascular complications, new permanent pacemaker insertions, moderate or severe paravalvular regurgitation, and coronary artery obstruction.

Life-threatening or major bleeding occurred less frequently with TAVR than with surgery. Results for left bundle-branch block and mild paravalvular regurgitation favored surgery.

The authors caution that the most important limitation of this trial is that the results reflect only 1-year outcomes and do not address the problem of long-term structural valve deterioration. "Definitive conclusions reading advantages and disadvantages of TAVR compared with surgery depend on longer-term follow-up," they state.   

A second trial of the use of TAVR in patients at low surgical risk, showing similar promising results with a different valve device — Medtronic's Evolut — is also to be presented at the same Late Breaking Clinical Trial session at ACC.19. The paper is also now off embargo because of the same embargo break and will be covered in a separate theheart.org | Medscape Cardiology report.

Further discussion from the meeting on the implications of the two trials will be covered in a follow-up news article.

The PARTNER 3 study was supported by Edwards Lifesciences. Leon reports grants/personal fees from Edwards Lifesciences, Medtronic, Boston Scientific, Gore Medical, Meril Lifesciences, and Abbott.    

American College of Cardiology 68th Annual Scientific Session (ACC) 2019. To be presented March 17, 2019.  

N Engl J Med. Published online March 16, 2017. Full text

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