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

BackgroundTo 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.MethodRV-PA coupling was measured noninvasively by Ea/Emax ratio from CMRI and ECHO. 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.ResultsNinety patients were uncoupled (Ea/Emax: 1.550.46) 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 a new concept of RV-PA interactions as a contributing mechanism for the observed decline in RV function.