A Pathophysiology-Integrated Nomogram to Predict Tricuspid Regurgitation Progression After Isolated Mitral Valve Surgery: A Retrospective Cohort Study.

BACKGROUND

Functional tricuspid regurgitation (FTR) frequently progresses after isolated mitral valve (MV) surgery in patients with pre-existing annular dilation, leading to adverse long-term outcomes. Notably, current guideline recommendations for concomitant tricuspid valve intervention, based primarily on annular size, lack precision for individualized risk prediction and may lead to both overtreatment and undertreatment.

METHODS

This retrospective, single-center cohort study included 398 patients with mild FTR and tricuspid annular dilation (>40 mm) who underwent isolated MV surgery (2010-2018). The primary endpoint was progression to at least moderate tricuspid regurgitation (TR) on the follow-up echocardiography. Multivariable logistic regression identified independent predictors. A nomogram was developed and internally validated via bootstrapping. Model performance was assessed using discrimination (area under the curve [AUC]), calibration (calibration plots and mean absolute error), and clinical utility (decision curve analysis [DCA] and clinical impact curve [CIC]).

RESULTS

TR progression occurred in 119 patients (29.9%) over a median follow-up of 5.2 years (interquartile range: 3.1-7.4). Multivariable analysis identified four independent preoperative predictors: atrial fibrillation type (paroxysmal: odds ratio [OR] 2.764, 95% confidence interval [CI] 1.682-4.532; persistent: OR: 3.422, 95% CI: 2.081-5.625; permanent: OR: 2.345, 95% CI: 1.404-3.917; all p < 0.001), tricuspid annular diameter index (per 1 mm/m2 increase: OR: 2.531, 95% CI: 1.767-3.649; p < 0.001), pulmonary artery systolic pressure (per 5 mmHg increase: OR: 3.246, 95% CI: 2.191-4.800; p < 0.001), and left atrial volume index (per 5 mL/m2 increase: OR: 1.876, 95% CI: 1.287-2.733; p = 0.001). The resulting nomogram demonstrated good discrimination, with an optimism-corrected AUC of 0.732 (95% CI: 0.701-0.763) following internal validation with 1000 bootstrap resamples (apparent AUC: 0.744; 95% CI: 0.712-0.797). The model also showed excellent calibration (calibration slope: 0.94; calibration-in-the-large: -0.03; Brier score: 0.152). DCA confirmed a superior net benefit relative to treat-all or no treatment strategies across threshold probabilities of 20-70%, with an optimal threshold of 45% for clinical decision-making.

CONCLUSIONS

This study developed and internally validated a pathophysiology-integrated nomogram accurately predicting the risk of TR progression after isolated MV surgery. This tool, which incorporates readily available preoperative variables, facilitates personalized risk stratification and evidence-based decision-making regarding concomitant tricuspid intervention, thereby potentially optimizing long-term outcomes for patients with functional tricuspid regurgitation.