Hold the knife: TAVR reduces the composite of death, stroke, and rehospitalization compared to open surgery even among low-risk patients with severe symptomatic AS

EBM Focus - Volume 14, Issue 7

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Reference: N Engl J Med 2019 Mar 17 (level 1 [likely reliable] evidence)

Trials have demonstrated that transcatheter aortic valve replacement (TAVR) results in similar mortality and lower risk of major bleeding and atrial fibrillation but higher risk of vascular complications for patients with severe, symptomatic aortic stenosis at intermediate or high surgical risk compared to surgical (open) aortic valve replacement (SAVR). However, no randomized trials have compared the two interventions in low surgical risk patients.

The PARTNER 3 trial is a randomized trial comparing TAVR versus SAVR among patients at low surgical risk. A thousand patients with severe, symptomatic aortic stenosis with a low risk of surgical mortality defined using the Society of Thoracic Surgeon Predicted Risk of Mortality (STS-PROM) calculator were randomized to open SAVR or TAVR. The protocol defined low-risk as an STS-PROM score of less than 4% surgical mortality at 30 days, a cut-off that was increased from 2% midway through the trial. Notably, patients with an ejection fraction less than 30% were excluded from the trial. Patients had an average age of 73 and average STS-PROM score of 1.9%. The TAVR group had more participants with NYHA III or IV heart failure (31.2% vs. 23.8%). The non-inferiority margin for the primary composite endpoint of death, stroke, or rehospitalization at 1 year was set at 6% difference between the two groups. A significantly higher number of patients randomized to SAVR dropped out of the trial (7 patients vs. 43 patients), leaving 496 in the TAVR arm and 454 in the SAVR arm.

In a per-protocol analysis, the rate of death, stroke, or rehospitalization was 8.5% in the TAVR group vs. 15.1% in the SAVR group, meeting the non-inferiority margin. In a prespecified, superiority analysis, there was a statistically significant reduction in the primary endpoint in the TAVR group vs. the SAVR group (hazard ratio 0.54, 95% CI 0.37-0.79). An intention-to-treat sensitivity analysis met both the prespecified non-inferiority and superiority margins for the primary composite outcome. There were fewer adverse events and complications in the TAVR group compared to the SAVR group. Patients in the TAVR group had lower rates of major bleeding requiring transfusion and atrial fibrillation requiring a new medication, shorter hospital stays, and higher rates of discharge home.

While the findings of this trial may be difficult to generalize due to its strict inclusion criteria and industry influence in recruitment, design, and analysis, evidence is accumulating in support of less invasive approaches to managing aortic stenosis. This trial demonstrates that among patients with a low risk of mortality, TAVR reduces the risk of death, stroke, and rehospitalization at 1 year while also reducing complications from surgical intervention. With the addition of this trial, a minimally invasive approach should be offered to patients of all risk categories with severe, symptomatic aortic stenosis.

For more information, see the topic Transcatheter aortic valve implantation (TAVI)/replacement (TAVR) in DynaMed Plus.


DynaMed Plus EBM Focus Editorial Team

This EBM Focus was written by Carina Brown, MD, Faculty Development and Information Mastery Fellow and Clinical Instructor at the University of Virginia. Edited by Alan Ehrlich, MD, Executive Editor at DynaMed Plus and Associate Professor in Family Medicine at the University of Massachusetts Medical School and Katharine DeGeorge, MD, MS, Assistant Professor in Family Medicine at the University of Virginia and Clinical Editor at DynaMed Plus.