Prognostic Value of Myocardial Contraction Fraction for One-Year Cardiac Death After Transcatheter Aortic Valve Implantation in Severe Aortic Stenosis: A Simple Echocardiographic Metric for High-Risk Stratification.

OBJECTIVE: Myocardial contraction fraction (MCF) is a volumetric index of myocardial shortening that relates left ventricular stroke volume to myocardial volume. In patients with severe aortic stenosis (AS), left ventricular ejection fraction (LVEF) may remain preserved despite advanced myocardial remodeling. This study aimed to evaluate the prognostic value of MCF for predicting 1-year cardiac death in patients undergoing transcatheter aortic valve implantation (TAVI). METHOD: This retrospective, single-center study included 419 consecutive patients with severe AS who underwent TAVI at a tertiary center. MCF was calculated by dividing stroke volume by left ventricular myocardial volume and multiplying the result by 100. Left ventricular myocardial volume was derived by dividing left ventricular myocardial mass by the myocardial density, which was assumed to be 1.05 g/mL. The primary endpoint was 1-year cardiac death. Receiver operating characteristic (ROC) curve analysis was used to identify the optimal MCF cutoff value, and the patients were divided into low- and high-MCF groups according to this threshold. RESULTS: The ROC-derived MCF cutoff value for predicting 1-year cardiac death was 24%, with an area under the curve of 0.783 (95% CI, 0.716-0.851), a sensitivity of 78.1%, and a specificity of 71.8%. Patients with MCF≤24% had lower LVEF and stroke volume index values, higher myocardial mass index and pulmonary artery pressure values, and larger left ventricular diameters than those with MCF>24%. One-year cardiac death occurred in 32 patients (7.6%) and was significantly more frequent in the MCF≤24% group than in the MCF>24% group (18.7% vs. 2.5%; P < 0.001). In univariable Cox regression analysis, MCF≤24% was strongly associated with 1-year cardiac death. In multivariable analysis, higher MCF, evaluated as a continuous variable, remained independently associated with a lower risk of 1-year cardiac death. CONCLUSION: Reduced MCF was associated with adverse left ventricular remodeling and increased 1-year cardiac death after TAVI. MCF may provide additional prognostic information beyond conventional echocardiographic parameters in patients with severe AS undergoing TAVI.