Impact of Tricuspid Regurgitation on Outcomes After Transcatheter Edge-to-Edge Repair for Primary Mitral Regurgitation: The PRIME-MR Registry.

BACKGROUND

The presence of tricuspid regurgitation (TR) may affect prognosis in patients with primary mitral regurgitation. This study sought to investigate the impact of concomitant TR on clinical outcomes in patients with primary mitral regurgitation undergoing mitral transcatheter edge-to-edge repair (M-TEER).

METHODS

The PRIME-MR registry (Outcomes of Patients Treated With Mitral Transcatheter Edge-to-edge Repair for Primary Mitral Regurgitation) included 3083 patients with severe primary mitral regurgitation undergoing M-TEER from 2008 to 2022 at 25 international sites. Only patients with successful M-TEER procedures (mitral regurgitation≤Moderate) were analyzed. The study population was stratified by baseline TR severity: TR≤Moderate (TR≤Mod) versus TR≥Severe (TR≥Sev). The primary end point was 2-year all-cause mortality.

RESULTS

A total of 2155 patients were analyzed: TR≥Sev (n=421 [20%]) versus TR≤Mod (n=1734 [80%]). Patients with TR≥Sev were more likely to be New York Heart Association III/IV (P=0.003), have shorter 6-minute walk distance (P<0.001), higher NT-proBNP (N-terminal pro-B-type natriuretic peptide; P<0.001), higher creatinine (P<0.001), higher pulmonary artery pressures (P<0.001), atrial fibrillation (P<0.001), and more diuretics (P<0.001) than those with TR≤Mod. At 2 years, patients with TR≥Sev had higher mortality (29.6% versus 19.6%; Plog-rank<0.0001) and heart failure hospitalization (21.1% versus 16.8%; PGray=0.018) than TR≤Mod. Baseline TR≥Sev was an independent predictor of 2-year mortality (adjusted hazard ratio, 2.01 [95% CI, 1.35-3.00]; P<0.001). Although TR≥Sev decreased in 30% of patients after successful M-TEER, residual TR≥Sev was still associated with higher mortality (30.4% versus 19.9%; Plog-rank=0.0037) than TR≤Mod.

CONCLUSIONS

In the PRIME-MR registry, 20% of patients with primary mitral regurgitation had severe TR at baseline. TR severity improved in 30% of TR≥Sev patients after successful M-TEER. The presence of TR≥Sev was independently associated with increased all-cause mortality at 2 years.