Morphological and functional types of tricuspid regurgitation: prognostic value in patients undergoing tricuspid annuloplasty during left-sided valvular surgery

Background The nonuniform benefit of tricuspid annuloplasty may be explained by the proportionality of tricuspid regurgitation (TR) severity to right ventricular (RV) area. The purpose of this study was to delineate distinct morphological phenotypes of functional TR and investigate their prognostic implications in patients undergoing tricuspid annuloplasty during left-sided valvular surgery. Methods The ratios of pre-procedural effective regurgitant orifice area (EROA) with right ventricular end-diastolic area (RVDA) were retrospectively assessed in 290 patients undergoing tricuspid annuloplasty. Based on optimal thresholds derived from penalized splines and maximally selected rank statistics, patients were stratified into proportionate (EROA/RVDA ratio ≤ 1.74) and disproportionate TR (EROA/RVDA ratio > 1.74). Results Overall, 59 (20%) and 231 (80%) patients had proportionate and disproportionate TR, respectively. Compared to those with proportionate TR, patients with disproportionate TR were older, had a higher prevalence of atrial fibrillation, lower pulmonary pressures, more impaired RV function, and larger tricuspid leaflet tenting area. Over a median follow-up of 4.1 years, 79 adverse events (47 heart failure hospitalizations and 32 deaths) occurred. Patients with disproportionate TR had higher rates of adverse events than those with proportionate TR (32% vs 10%; P = 0.001) and were independently associated with poor outcomes on multivariate analysis. TR proportionality outperformed guideline-based classification of TR severity in outcome prediction and provided incremental prognostic value to both the EuroSCORE II and STS score (incremental χ 2 = 6.757 and 9.094 respectively; both P < 0.05). Conclusions Disproportionate TR is strongly associated with adverse prognosis and may aid patient selection and risk stratification for tricuspid annuloplasty with left-sided valvular surgery. Graphical Abstract