Pulmonary Valve Replacement Improves But Does Not Normalize Right Ventricular Mechanics in Repaired Congenital Heart Disease: A Comparative Assessment Using Velocity Vector Imaging

Abstract

This study evaluated regional right ventricular (RV) mechanics before and after pulmonary valve replacement (PVR) by ultrasonic speckle tracking technology using velocity vector imaging (VVI). Fifty-eight patients who underwent PVR (May 1999 to August 2007) were included. Two-dimensional Doppler indices included qualitative pulmonary incompetence, RV outflow tract peak gradient, RV systolic pressure estimate, indexed RV area, and fractional area change; VVI regional indices included peak systolic and diastolic velocities, peak systolic strain, maximal longitudinal displacement, and times to peak measure from 6 RV segments. PVR was performed at a median age of 12.1 years with echocardiographic analysis at median intervals of 2.8 months before and 30 months after PVR. Peak velocities and displacement increased in all 6 RV segments after PVR; peak systolic strain did not improve consistently. All indices remained significantly lower compared with normal values. There was a significant decrease in the degree of pulmonary incompetence, RV outflow tract gradient, RV systolic pressure, and indexed RV area (23.5 vs. 17.8 cm(2)/m(2)), but no significant change in the percentage of fractional area change (28.8% vs. 29.6%). Regional RV mechanics using VVI in a relatively young cohort shows mild improvement after PVR, but the RV is not normalized despite physiologic improvement in loading conditions. This suggests intrinsic dysfunction or chronic myocardial injury that is nonmodifiable or requires earlier intervention to optimize physiology. VVI appears to be a potentially useful quantitative tool for follow-up evaluation of RV performance after congenital heart disease surgery.