Evaluation of right ventricle pulmonary artery coupling on right ventricular function in post operative Tetralogy of Fallot patients underwent for pulmonary valve replacement

Abstract Background: The aim of this study is to evaluate RV-PA coupling in post operative TOF patients with ventricular dilatation underwent for PVR and investigate the correlation between ventricular functions measuring Ea/Emax ratio using cardio magnetic resonance and the effect of surgical type at primary repair of TOF on coupling.Method: 135 TOF patients after TOF repair were retrospectively included. From CMRI results the patients were divided in two groups, RV-PA coupling and RV-PA uncoupling. Ea/Emax ≤1 was considered for coupling patients and Ea/Emax >1 for uncoupling patients.Results : 90 patients were uncoupled (Ea/Emax: 1.55±0.46) and 45 were coupled (Ea/Emax: 0.81±0.15). Out of 75 TAP repaired patients 60 were uncoupled RV-PV. In addition, higher pro-BNP is an important factor for uncoupled RV-PV ( P =0.001). CMR evaluation for right ventricular function between uncoupling and coupling were RVEDVi (196.65±63.57 vs. 154.28±50.07, P =0.001), RVESVi (121.19±51.47 vs. 83.94±20.43, P =0.001), RVSVi (67.19±19.87 vs. 106.31±33.44, P =0.001), and RVEF (40.90±8.73 vs. 54.63±4.76, P =0.001). The increased RVEDVi, RVESVi and RVSVi and decreased RVEF have significant correlation with Ea/Emax. Ea/Emax was also found positively correlated with RVEDVi ( P=< 0.05, r =0.35), RVESVi ( P=< 0.001, r =0.41) and negatively correlated with RVSVi ( P=< 0.05, r =0.22) and RVEF ( P=< 0.05, r =0.78).Conclusions: Unfavorable RV-PA coupling is present in post operative TOF patients and it is affected by several factors. Our results explain the emerging role of RV-PA interactions as a contributing mechanism for the observed decline in RV function.