Survival and Long-Term Outcomes Following Bioprosthetic vs Mechanical Aortic Valve Replacement in Patients Aged 50 to 69 Years

Study Questions:

Based on tissue versus mechanical valve implantation, what are the survival and major morbidity outcomes for patients, ages 50-69 years, undergoing aortic valve replacement (AVR)?

Methods:

A retrospective cohort analysis was performed using 4,253 patients, ages 50-69 years, who underwent primary isolated AVR using bioprosthetic versus mechanical valves in New York State from 1997-2004, who were identified using the Statewide Planning and Research Cooperative System. Median follow-up time was 10.8 years (range 0-16.9 years); the last follow-up date for mortality was November 30, 2013. Propensity matching yielded 1,001 patient pairs.

Results:

No differences in survival or stroke rates were observed in patients with bioprosthetic compared with mechanical valves. Actuarial 15-year survival was 60.6% (95% confidence interval [CI], 56.3%-64.9%) in the bioprosthesis group compared with 62.1% (95% CI, 58.2%-66.0%) in the mechanical prosthesis group (hazard ratio [HR], 0.97; 95% CI, 0.83-1.14). The 15-year cumulative incidence of stroke was 7.7% (95% CI, 5.7%-9.7%) in the bioprosthesis group and 8.6% (95% CI, 6.2%-11.0%) in the mechanical prosthesis group (HR, 1.04; 95% CI, 0.75-1.43). The 15-year cumulative incidence of reoperation was higher in the bioprosthesis group (12.1%; 95% CI, 8.8%-15.4% vs. 6.9%; 95% CI, 4.2%-9.6%; HR, 0.52; 95% CI, 0.36-0.75). The 15-year cumulative incidence of major bleeding was higher in the mechanical prosthesis group (13.0%; 95% CI, 9.9%-16.1% vs. 6.6%; 95% CI, 4.8%-8.4%; HR, 1.75; 95% CI, 1.27-2.43). The 30-day mortality rate was 18.7% after stroke, 9.0% after reoperation, and 13.2% after major bleeding.

Conclusions:

Among propensity-matched patients, ages 50-69 years, who underwent isolated AVR with bioprosthetic compared with mechanical valves, there was no significant difference in 15-year survival or stroke. After bioprosthetic AVR, patients had a greater likelihood of reoperation, but a lower likelihood of major bleeding. These findings suggest that bioprosthetic valves may be a reasonable choice in patients ages 50-69 years.

Perspective:

Traditional age thresholds for tissue versus mechanical valve replacement are based in part on two randomized trials performed in the 1970s and early 1980s, which used outdated prostheses and were associated with excessive (compared to current) reoperative risks. Although well-informed patient preference plays a primary role in current guidelines, data from this well-constructed study help reinforce other publications that similarly suggest that mortality is not affected by tissue versus mechanical valve choice. Decisions about valve type at the time of AVR should be based in most cases on lifestyle preferences (avoiding re-operation vs. avoiding warfarin and bleeding risk). Further impacting the same topic is the advent of valve-in-valve transcatheter AVR (TAVR), which allows many patients with degeneration of a bioprosthesis to undergo a transcatheter rather than a repeat surgical procedure.

Clinical Topics: Cardiac Surgery, Aortic Surgery

Keywords: Heart Valve Prosthesis, Stroke, Life Style, Reoperation, Aortic Valve, Bioprosthesis, Patient Preference, Hemorrhage, Treatment Outcome


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