Prognostic utility of a risk prediction model for predischarge major residual lesions or unplanned reinterventions following congenital mitral valve repair.

Objective: We sought to develop a risk prediction model for predischarge major mitral valve (MV) residual lesions or unplanned MV reinterventions following congenital MV repair.

Methods: Patients who underwent congenital MV repair (excluding primary repair, but including secondary repair, of canal-type defects) at a single institution from January 2000 to December 2020 and survived to discharge were retrospectively reviewed. The primary outcome was major MV residua (mean gradient >6 mm Hg or moderate or greater regurgitation on the discharge echocardiogram) or predischarge unplanned MV reintervention. Risk factors of interest included age, single-ventricle physiology, preoperative and intraoperative postrepair MV stenosis and regurgitation severity, MV annular diameter z score, systemic ventricle ejection fraction, unfavorable anatomy, concomitant left-heart procedure, and various technique-related categories. Logistic regression was used to develop a weighted risk score for the primary outcome. Internal validation using bootstrap-resampling was performed.

Results: Of 866 patients who underwent congenital MV repair at a median age of 2.7 years (interquartile range, 0.7-9.1 years), 202 (23.3%) patients developed the primary outcome. The final risk prediction model had a C-statistic of 0.82 (95% confidence interval, 0.78-0.85). A weighted risk score was formulated per the variables in this model. The median risk score was 8 (interquartile range, 6-11) points. Patients were categorized as low (score 0-5), medium (score 6-10), high (score 11-15), or very high (score ≥16) risk. The probability of the primary outcome was 5.0 ± 1.7%, 15.2 ± 6.7%, 45.9 ± 12.6%, and 76.7 ± 8.8% for low-, medium-, high-, and very-high-risk patients, respectively.

Conclusions: Our risk prediction model may guide prognostication of patients following congenital MV repair.