Risk stratification for isolated tricuspid valve surgery assisted using the Model for End-Stage Liver Disease score

Objective: Isolated tricuspid valve surgery is perceived as high-risk. This perception is nurtured by patients who often present with substantial liver dysfunction, which is inappropriately reflected in current surgical risk scores (eg, the Society of Thoracic Surgeons [STS] score has no specific tricuspid model). The Model for End-Stage Liver Disease (MELD) has was developed as a measure for the severity of liver dysfunction. We report scores and outcomes for our patient population. Methods: We calculated STS, European System for Cardiac Operative Risk Evaluation (EuroSCORE) II (ESII), and MELD scores for all of our patients who received isolated tricuspid valve surgery between 2011 and 2020 (n = 157). We determined the MELD score, stratified patients into 3 groups (MELD <10: low, n = 53; 10 to <20: intermediate, n = 78; >= 20: high, n = 26) and describe associated outcomes. Results: Patients were 72 +/- 10 years old and 43% were male. Mean STS score was 4.9 +/- 3.5% and ESII was 7.2 +/- 6.6%. Mortality was 8.9% at 30 days and 65% at latest follow-up (95% CI, 51%-76%). Median follow-up was 4.4 years (range, 0-9.7 years). Although ESII and STS score accurately predicted 30-day mortality at low MELD scores (observed to expected [O/E] for ESII score = 0.8 and O/E for STS score = 1.0) and intermediate MELD (O/E for ESII score = 0.7, O/E for STS score = 1.0), mortality was underestimated at high MELD (O/E for ESII score = 3.0, O/E for STS score = 4.7). This subgroup also had higher incidence of new-onset hemodialysis. Besides MELD category, recent congestive heart failure, endocarditis, and hemodialysis were also associated with 30-day mortality. Conclusions: For isolated tricuspid valve regurgitation, classic surgical risk stratification with STS or ESII scores failed to predict perioperative mortality if there was evidence of severe liver dysfunction. Preoperative MELD assessment might be useful to assist in proper risk assessment for isolated tricuspid valve surgery.