The estimated plasma volume status is an independent predictor for mortality in patients undergoing transcatheter mitral valve repair

INTRODUCTION: Fluid overload and congestion are common in patients with mitral regurgitation and are associated with poor outcome and increased mortality. However, assessment for subclinical congestion in patients undergoing transcatheter edge-to-edge mitral valve repair (M-TEER) remains challenging. Besides the established natriuretic peptides like NT-proBNP, the estimated plasma volume status (ePVS) has emerged as a prognostic marker for intravascular congestion in heart failure and valvular heart disease. This study evaluated the prognostic impact of preprocedural ePVS in patients undergoing M-TEER. METHODS: 311 patients undergoing M-TEER were prospectively enrolled. The ePVS as the difference between actual and ideal plasma volume was calculated based on Hakim's formula using hematocrit, body weight and sex dependent constants. Follow-up data were collected regularly after M-TEER. Based on 1-year mortality, cut-off values for ePVS and NT-proBNP were calculated. RESULTS: Median ePVS was -3.8% (IQR -10.3% to 3.6%). An elevated ePVS above the cut-off was associated with higher Kaplan-Meier-estimated mortality at 1 year (14.4% vs. 4.7%) and 5 years (63.0% vs. 26.0%; log-rank p<0.001). Elevated ePVS and NTproBNP remained independently associated with mortality after multivariable adjustment (ePVS: HR 2.38, 95%CI 1.20-4.74; p=0.013; NT-proBNP: HR 4.30, 95%CI 1.50-12.31; p=0.007). Their combined assessment provided further risk stratification, with the highest risk in patients with both markers elevated compared with neither (HR 14.27, 95%CI 3.19-63.89; p<0.001). CONCLUSION: Elevated preprocedural ePVS and NT-proBNP were independent predictors of mortality after M-TEER. Their combined assessment provided further risk stratification and may improve risk assessment in this heterogeneous population.