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

Abstract 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.