Preoperative Prediction Models for 30-Day All-Cause Mortality After Mitral Valve Repair in Dogs: A Single-Center Retrospective Cohort Study.

Abstract

BACKGROUND: Mitral valve repair (MVR) has emerged as a novel surgical intervention for dogs with myxomatous mitral valve disease (MMVD). However, no objective risk assessment method has been established for these cases. OBJECTIVES: The primary aim of this study was to develop and evaluate preoperative prediction models for 30-day postoperative mortality in dogs undergoing MVR. The secondary aim was to assess the association between short-term predictive risk and long-term mortality following MVR. ANIMALS: A total of 2089 client-owned dogs with MMVD that underwent MVR between 2016 and 2023 were included. METHODS: This was a single-center retrospective cohort study. Preoperative variables including demographic data, routine blood test results, diagnostic imaging examination data, and medication history were selected as predictor candidates. Prediction models for 30-day all-cause mortality were developed using these variables and shrinkage estimation methods, and the model performances were evaluated. The association between the predicted probabilities and 2-year cumulative all-cause mortality was assessed using Cox proportional hazards analysis. RESULTS: The 30-day all-cause mortality rate after MVR was 4.9% (102/2089). The best preoperative prediction model for 30-day all-cause death demonstrated low-to-moderate discrimination abilities (c-statistics, 0.654) and good calibration performance (slope = 1.003; intercept = 0.007; E = 0.002) in internal validation. The quartile grouping of the predicted 30-day all-cause mortality risk was associated with 2-year mortality. CONCLUSIONS AND CLINICAL IMPORTANCE: The preoperative prediction model for short-term mortality in dogs undergoing MVR demonstrated acceptable predictive performance. The prediction model may provide an objective preoperative risk assessment in dogs undergoing MVR at this center.