Discongruence Index ― Simple Indicator to Predict Prosthesis-Patient Mismatch After Transcatheter Aortic Valve Replacement ―

BACKGROUND: Prosthesis-patient mismatch (PPM) after transcatheter aortic valve replacement (TAVR) remains an important issue. The aim of this study was to assess the value of a new discongruence index, to predict PPM after TAVR.Methods and Results: A total of 185 patients with severe aortic stenosis who underwent TAVR with the Edwards Sapien prosthesis or CoreValve Revalving system were included (Edwards valve, n=119; Core Valve Revalving system, n=66). Discongruence index was calculated pre-procedurally as the ratio of selected transcatheter valve size (mm) to body surface area (cm2). PPM was defined as effective orifice area (EOA) ≤0.85 cm2/m2 on transthoracic echocardiography before hospital discharge. Mean age was 82±5 years and 72 patients (38.9%) were men. The overall incidence of post-TAVR PPM was 35.1% (n=65). Discongruence index correlated with post-TAVR indexed EOA (y=0.18+0.057x; P<0.001). On multivariate logistic regression analysis, discongruence index was the only independent predictor of post-TAVR PPM (OR, 0.15; 95% CI: 0.03-0.66; P=0.012), and the area under the receiver operating characteristic curve was 0.62 (95% CI: 0.54-0.70, P=0.003), with an optimal cut-off point of 15.02 (sensitivity, 86.2%; specificity, 72.5%; positive predictive value, 74.3%; negative predictive value, 83.4%). CONCLUSIONS: The new discongruence index may be useful tool to predict PPM after TAVR.