Abstract 18777: Right Ventricular Outflow Tract Strain is Reduced in Tetralogy of Fallot Compared to Valvar Pulmonary Stenosis Patients; Regional RV Function Defined by Strain Cardiac Magnetic Resonance Imaging

Abstract

Introduction: The right ventricular outflow tract (RVOT) patch after Tetralogy of Fallot (ToF) surgery may contribute to ventricular dysfunction, but the specific effects on RV function are not clear. We aimed to investigate RV function in patients with ToF and RVOT patch by comparing to patients with valvar pulmonary stenosis (vPS) after balloon valvuloplasty (no RVOT patch). Methods: We conducted a retrospective review of 33 CMR studies of ToF and vPS patients with similar pulmonary regurgitation (PR) Table 1. Feature tracking strain (FTS) analysis of balanced steady state free precession (SSFP) cines was performed on the RV in apical 4-chamber (4ch), RVOT sagittal & mid-RV short axis views (TomTec 2D Cardiac Performance Analysis, v1.0), Figure 1. Unpaired t-tests were applied for comparison of means between groups. Results: Lagrangian longitudinal strain (LS) at the RVOT was significantly lower in ToF compared to vPS (mean -14.1% vs -18.2%, unpaired t-test p = 0.03), Table 1. Analysis of regional S within the same group showed a trend towards lower RVOT strain compared to 4ch LS in ToF (p = 0.052). There were no significant inter-group differences in strain from the 4ch or mid-RV short axis views, with normal 4ch LS in both groups. Conclusion: In a population with preserved EF, RVOT strain is significantly lower in ToF patients with a transannular patch compared to vPS patients with similar amount & duration of PR. Low RVOT LS appears to be a regional phenomenon, with strain in the 4ch and mid-RV similar between groups. Further investigation is warranted in a larger sample. FTS analysis is a promising technique to evaluate regional RV mechanics in this population.