Abstract 5781: Evaluation of Global and Regional Right Ventricular Systolic Function in Patient Prosthesis Mismatch after Mitral Valve Replacement using Velocity Vector Imaging
The aim of this study was to compare right ventricular (RV) global and regional systolic function in patients with and without patient prosthesis mismatch (PPM) after isolated mitral valve replacement (MVR) using Velocity Vector Imaging (VVI) method. The PPM group consisted of 20 patients that underwent isolated MVR with an indexed effective orifice area (EOA) ≤ 1.2 cm2/m2 determined by continuity equation and indexed for body surface area. The non-PPM group consisted of 20 patients that also underwent isolated MVR with an indexed EOA > 1.2cm2/m2. Echocardiographic images in apical planes were analyzed for RV volumes, ejection fractions, myocardial velocity, strain and strain rate at the basal, mid and apical segments of RV free wall and ventricular septum using VVI. The demographic and preoperative data were similar between PPM and non-PPM groups. Evidence of PA hypertension defined as systolic PA pressure > 40 mmHg was present in 50% of patients in PPM group, whereas none of the patients in non-PPM group had PA hypertension. RV volumes were significantly increased, and RV ejection fraction, peak systolic myocardial velocities, strain and strain rates were significantly impaired in patients with PPM compared to non-PPM group (p<0.001 for all). Indexed EOA correlated strongly with myocardial velocities, strain and strain rates in all segments of the RV (p<0.05 for all). Multivariate stepwise regression analysis demonstrated that indexed EOA and systolic PA pressure were the independent determinants of basal free wall peak systolic strain (β=0.547, p<0.001 and β=−0.304, p=0.033 respectively) and strain rate (β=0.497, p=0.001 and β=−0.332, p = 0.026 respectively). Using receiver-operating characteristics analysis cut-off values for basal free wall peak systolic strain and strain rate in determining patients with indexed EOA ≤ 1.2 cm2/m2 were −25.62 % (sensitivity 85%, specificity 95%) and −1.87 1/s (sensitivity 95%, specificity 95%) respectively. PPM after MVR is associated with RV global and regional RV dysfunction. Two-dimensional echocardiography has some limitations in evaluating RV function due to its complex geometry. VVI is a feasible modality in assessment of RV global and regional RV function.