AHA: Tissue Heart Valves Do Not Impair Survival in Young Adults

CHICAGO, Nov. 15 -- Young patients survive as long with a bioprosthetic heart valve as with a man-made replacement, researchers here said.

In a finding that defies conventional wisdom, 20- and 25-year survival rates after receiving a new heart valve were non-significantly higher for organic valves, reported Vincent Chan, M.D., of the University of Ottawa in Ontario and colleagues, at the American Heart Association meeting.

Among the 296 patients followed for 20 to 35 years after valve replacement at age 18 to 50, the researchers found better survival for aortic tissue valves at 20 years (72% 4.3% versus 59.9 6.0%) and 25 years (64.% 5.8% versus 47.2% 7.4%).

However, there was no significant difference at either time point (hazard ratio 0.8 for bioprosthesis, 95% confidence interval 0.5 to 1.2, P=0.3) after adjusting for comorbid factors, such as high blood pressure and coronary artery disease.

"Many believe that as decades pass, young adults with bioprostheses may be exposed to undue cumulative risk from multiple reoperations," Dr. Chan said.

Mechanical valves are considered more durable, meaning fewer lifetime valve replacement procedures, but they can lead to increased clot formation and therefore higher stroke risk and elevated bleed risk from the anticoagulant medication required.

"Based on our data, young patients should not be precluded from having tissue valves," he added, with the decision based on patient compliance, monitoring and patient preference instead.

The observational study included patients at a single Canadian center who underwent left-side valve replacement or prosthesis replacement as young adults.

The investigators did find significantly lower long-term survival for patients who had their mitral valve replaced compared to aortic valve replacement (HR 1.5, 95% CI 1.1 to 2.1, P=0.004). Again, the replacement valve material appeared not to affect survival between the two valve location groups (HR for tissue valve 0.9, 95% CI 0.5 to 1.4, P=0.5).

Rather, the strongest predictor of mortality was the presence of concomitant coronary artery disease (CAD HR 1.9, 95% CI 1.2 to 3.0, P=0.01).

"Even within the subgroup of young adults with coronary artery disease, no prosthesis class proved superior to the other," Dr. Chan said.

While adult valve replacement candidates are typically older than 50, "the implications are just as important if not more important in this [young] age group," he said.

Pediatric patients were excluded from the study as they typically have right-side valve replacements for congenital heart problems. In adults, valves are typically replaced for stenosis or being "too leaky," insufficiency of regurgitation.

The researchers cautioned that the study was meant to be hypothesis generating and did not constitute a recommendation for either type of replacement valve.

One of the authors reported "modest" research and follow-up clinic support from valve companies.