No differences were seen in the 15-year stroke or survival rates in more than 4,000 propensity-matched patients in the age range of 50-69 years who received either a mechanical or a bioprosthetic aortic valve replacement, according to the results of a retrospective cohort analysis.
However, valves differed in two other major complications, according to a report published in the Oct. 1 issue of JAMA. Mechanical valve patients had a significantly higher 15-year cumulative incidence of bleeding compared with the bioprosthetic valve group, but had a significantly lower 15-year cumulative incidence of reoperation, according to Yuting P. Chiang and colleagues at the Icahn School of Medicine at Mount Sinai and Mount Sinai Medical Center, New York.
This study calls into question current practice guidelines, which recommend either a bioprosthetic or mechanical prosthetic aortic valve in patients aged 60-70 years, and a mechanical valve in patients younger than 60 years in the absence of a contraindication to warfarin (Coumadin), according to the researchers.
From an original population of more than 10,000 patients aged 50-69 with valve replacement, 4,253 remained after researchers applied exclusionary criteria such as prior valve repair and coronary artery bypass grafting. Of these, 1,466 (34.5%) received a bioprosthetic aortic valve replacement, and 2,787 received a mechanical valve.
Median follow-up was 10.6 and 10.9 years, respectively. Propensity scoring matching produced 1,001 patient pairs. After propensity matching, age and all baseline comorbidities were balanced between the two groups.
Overall, there were no differences in 30-day mortality in the matched groups (3% in both), nor in any other short-term outcome (JAMA 2014;312:1323-29).
In terms of long-term survival, there were no differences seen in the matched cohort, with an actuarial 15-year survival of 60.6% for the prosthetic valve group, and 62.1% for the mechanical valve group (P = .74).
Similarly, there was no significant difference in the cumulative 15-year stroke rate (7.7% for the bioprosthetic group, 8.6% for the mechanical group, P = .84). The 30-day mortality rate after stroke was 18.7%.
There was a significantly higher rate of aortic valve reoperation in the bioprosthetic group (cumulative 15-year incidence of 12.1%) compared with the mechanical group (cumulative incidence of 6.9%, P = .001). The 30-day mortality rate after aortic valve reoperation was 9.0%.
In contrast, cumulative major bleeding over 15 years was significantly higher in the mechanical group (13.0%), than in the bioprosthetic group (6.6%, P = .001). Thirty-day mortality after a major bleeding event was 13.2%.
In discussing the differences between this study and the randomized clinical trials that contributed to the class IIa recommendations on age-based valve choice, the researchers pointed out that two of the studies “enrolled patients nearly 4 decades ago and evaluated prostheses since superseded by more durable and less thrombogenic models.”
The analysis “supports the view that either prosthesis is a reasonable choice in patients aged 60 to 69 years and suggests that this recommendation could reasonably be extended to patients aged 50 to 59 years,” they concluded.
Potential problems inherent in a database analysis and the tendency for deaths at a younger age to be missing from the Social Security Death Master File were limitations of the study. Younger patients were more likely to receive a mechanical valve.
Mr. Chiang reported a research stipend from the Icahn School of Medicine, which receives royalty payments from Edwards Lifesciences and Medtronic related to two mitral valve and 1 tricuspid valve ring that Dr. David H. Adams, a coauthor, helped develop. Dr. Adams is coprincipal investigator for the CoreValve United States pivotal trial, supported by Medtronic.