Introduction and methods

Transcatheter or Surgical Aortic Valve Replacement in Low-Risk Patients: Results of the PARTNER 3 Trial

Presented at ACC.19 by Martin Leon (Columbia University, New York, NY, USA)

PARTNER 3 is the fifth randomized trial of the PARTNER series of studies, which collectively includes over 9,000 patients with severe aortic stenosis. The program compares transcatheter aortic valve replacement (TAVR) with conventional surgery. The earliest trials evaluated TAVR in very sick patients who often cannot be treated with surgery. Subsequent PARTNER studies moved down the spectrum of risk. This study was performed in patients at low surgical risk (STS <4%, assessed by Heart Team), which comprise the majority of patients who are candidates for surgery to have their aortic valve replaced.

PARTNER 3 randomized 1000 patients to TAVR using the SAPIEN 3 valve or surgery, using a surgical bioprosthetic valve. Follow-up was at 30 days, after 6 months and annually up to 10 years. The primary endpoint was a composite of all-cause mortality, stroke, or CV re-hospitalization at 1 year post-procedure. A more expansive endpoint was chosen to reflect these patients at low surgical risk.

Main results

• The primary endpoint at 1 year was seen in 15.1% of patients randomized to surgery and in 8.5% in those undergoing TAVR (P-non-inferiority <0.001). When testing for superiority, an HR of 0.54 (95%CI: 0.37-0.79, P=0.001) was seen.
• Death or disabling stroke was seen less often in those assigned to TAVR as compared with surgery (1.0% vs 2.9% at 1 year, HR: 0.34, 95%CI: 0.12-0.97, P=0.03).
• Pre-specified endpoints that were significantly reduced in the TAVR vs surgery group included: new onset atrial fibrillation at 30 days (5% vs. 39.5%), length of index hospitalization (3.0 vs. 7.0 days), all-cause death, all stroke or rehospitalization at 1 year (8.5% vs. 15.1%), death, KCCQ <45 or KCCQ decrease ≥10 points from baseline at 30 days (3.9% vs. 30.6%), death or all stroke at 30 days (1.0% vs. 3.3%) and all stroke at 30 days (0.6% vs. 2.4%.
• Other significantly altered secondary endpoints were less bleeding, both life-threatening and major with TAVR at 30 days (3.6% vs. 24.5%) and at 1 year (7.7% vs. 25.9%), and more left bundle branch block at 30 days (22.0% vs. 8.0%) and at 1 year (23.7% vs. 8.0%).
• The occurrences of moderate or severe paravalvular regurgitation were similar in both treatment arms at 30 days and at 1 year.

Conclusion

Based on these findings of up to 1 year after the procedure, TAVR should be considered the preferred therapy in aortic stenosis patients with low surgical risk. The PARTNER randomized trial conducted over the past 12 years indicate that the relative value of TAVR over surgery is independent of surgical risk profiles. Thus, the investigators think that the choice of TAVR vs. surgery in aortic stenosis patient should be a shared-decision making process, with respect for patient preferences and understanding of knowledge gaps, and considering clinical and anatomic factors.

Longer term follow-up is needed to ascertain that the transcatheter valves are as durable as surgical valves. The patients of PARTNER 3 will be followed for 10 years.

Discussion

Discussant Janet Wyman (Detroit, MI, USA) complimented the PARTNER study investigators with their beautiful series of studies. She summarized the results by saying that they did not induce a paradigm shift, but rather a complete flip. The conversation with patients should now be completely different. She noted that we need to think about what resources need to be changed, in order to be able to offer these interventions. That will lead to better physiological outcomes and will be better aligned with patients’ preferences and lives.

Interestingly, in the same session, the results of the Evolut low risk trial were presented by dr. Michael J Reardon , on self-expanding transcatheter or surgical aortic valve replacement. This study showed that TAVR with self-expanding valves was non-inferior to surgery in patients with severe aortic stenosis at low risk of surgical mortality. TAVR showed a better safety and recovery profile than surgery, with less death or disabling stroke, less disabling stroke, shorter length of stay and better quality of life. SAVR on the other hand showed fewer pacemakers implanted and less residual AR at 30 days. Both groups had excellent survival at 1 year, with TAVR showing fewer disabling strokes and heart failure rehospitalizations with superior hemodynamics.

Based on these data, dr. Reardon agreed with dr. Leon that TAVR is no longer an alternative therapy; it should be the preferred therapy. He said that if he does not offer it to a patient, he has not provided good treatment. The discussant Joseph Cleveland (Aurora, CO, USA) said these data reaffirm that a paradigm flip has taken place. He noted that surgery was always the gold standard, because there was nothing to compare it against, but now there is a comparator.

- Our coverage of ACC.19 is based on the information provided during the congress -

Watch the video of the PARTNER-3 trial