Valve failure following homograft aortic valve replacement: does implantation technique have an effect?

Abstract

Structural valve deterioration (SVD) limits the long-term durability of homograft aortic valve replacement (AVR). Valves are implanted predominantly using two techniques, the free-hand sub-coronary (SC) technique or aortic root replacement (RR). Our objective was to identify risk factors associated with the development of SVD or ascending aortic dilatation. In particular we strived to determine whether the mode of implantation had an independent effect. Demographic and pre-operative clinical data were obtained retrospectively through case-note review. All operations were performed by a single surgeon. Actuarial freedom from >or=2+ AR (aortic regurgitation), elevated trans-valvular gradient (TVG) (>or=25 mmHg) and ascending aortic dilatation (>or=4.0 cm) were assessed using Kaplan-Meier curves and multivariable Cox proportional hazards regression. A propensity analysis was carried out using a non-parsimonius logistic regression model for implantation with SC vs. RR. Between 1 January 1991 and 1 January 2001, 215 patients underwent AVR with a homograft. The SC technique was used in 131 (61%) patients and 84 (39%) patients underwent RR. Technique was not an independent predictor for >or=2+ AR (adjusted hazard ratio 1.9; 95% CI 0.56-6.16, P = 0.31), elevated TVG (adjusted hazard ratio; 0.99; 95% CI 0.15-6.71, P = 0.99) or ascending aortic dilatation (adjusted hazard ratio 2.01; 95% CI 0.50-8.25, P = 0.33). One and 5 year actuarial freedom from >or=2+ AR (log-rank - P = 0.09) and ascending aortic dilatation (log-rank - P = 0.88) were not significantly different between groups. The incidence of SVD and ascending aortic dilatation is not affected by the method of implantation of the aortic homograft. All homografts are prone to SVD which is responsible for a progressive increase in the prevalence of these changes over time.