Prognostic impact of myocardial contraction fraction in patients undergoing transcatheter aortic valve replacement for aortic stenosis

Myocardial contraction fraction (MCF), a volumetric measurement of myocardial shortening, may help to improve risk stratification in patients with severe aortic stenosis (AS) referred for transcatheter aortic valve replacement (TAVR) especially in those with preserved left ventricular ejection fraction (LVEF). We investigated the association between MCF and 1-year all-cause mortality in patients with severe AS who underwent TAVR. MCF was calculated as the ratio of stroke volume (SV) to myocardial volume. Patients referred for TAVR from 2011 to 2015 were eligible for inclusion and were divided into two groups according to the estimated MCF (MCF ≤30% MCF >30%). The primary endpoint was 1-year all-cause mortality. A Cox regression analysis was performed for independent risk factors of mortality. Receiver operating curve (ROC) was performed for assessing the best cut-off point of MCF for predicting the primary outcome [area under the curve (AUC) 0.60; 95% confidence interval (CI): 0.453-0.725]. Baseline patient and echo characteristics were included for multivariate analysis. Of 126 patients (mean age 82±5 years, 45.2% male), 44.4% showed MCF ≤30%. Patient with reduced MCF showed higher body mass index (28.1±5.8 26.0±4.5 kg/m , P=0.031), higher surgical EuroScore II (6.2±4.5 4.7±3.2, P=0.032), lower LVEF (54.2%±11.9% 58.5%±10.8%, P=0.042) and more severe AS (indexed aortic valve area 0.40±0.09 0.45±0.10 cm /m , P=0.030). The median follow-up was of 14 [3.5-33] months, and 16% of patients died. Patients with MCF ≤30% showed significantly increased all-cause mortality (Log-rank P=0.002). In a multivariate model adjusting for clinical and echo variables, MCF ≤30% was independently associated with increased risk for all-cause 1-year mortality [hazard ratio (HR) 2.76, 95% CI: 1.03-7.77, P=0.04]. In a population of patients undergoing TAVR, MCF ≤30% was independently associated with increased mortality.