Indications for and characteristics of redo aortic valve replacement after primary mechanical aortic valve replacement

Objective To define the indications and characteristics for redo aortic valve replacement (AVR) after primary mechanical AVR and to determine whether operative indication influences early and late outcomes. Methods We analyzed 379 consecutive patients undergoing redo AVR after previous mechanical AVR (2000-2023) at a single tertiary center. Baseline, operative, and outcomes data were obtained from a prospectively maintained database and electronic health records. Outcomes were compared across principal indications, with survival estimated by Kaplan-Meier analysis and predictors of mortality identified using multivariable Cox regression. Results Median age at redo surgery was 61.8 years (interquartile range, 52.4-69.4 years); 61.2% were male. The median interval to reoperation was 10.2 years (3.9-18.2). Indications included endocarditis (26.6%), pannus obstruction (18.7%), prosthesis-patient mismatch (11.6%), and elective replacement during aortic surgery (16.0%). Endocarditis cases were frequently nonelective and had longer operative times, greater complication rates, and greater operative mortality (13.0% vs 1.4% pannus and 3.4% others; P < .001). Independent predictors of all-cause mortality were older age, diabetes, dialysis dependence, previous myocardial infarction, and nonelective surgery. Indication, including endocarditis, and valve size were not independent predictors. Lower overall survival in endocarditis and bioprosthetic redo cases reflected excess early mortality; beyond 1 year, survival was similar across indications. Conclusions Redo AVR after previous mechanical AVR is uncommon and arises from heterogeneous indications. Early risk is greatest with endocarditis and nonelective presentation, whereas long-term survival is driven largely by comorbidities rather than indication or prosthesis type. These findings may guide risk assessment, prosthesis selection, and timing of intervention.