Impact of Flow Differentials According to Cardiac and Respiratory Cycles on Three Types of Fontan Operation.

Few hemodynamic comparison studies on various types of Fontan operation have been reported. The objective of this study was to perform hemodynamic comparisons for flow size and volume in three types of Fontan operation: atriopulmonary connection (APC), lateral tunnel (LT), and extracardiac conduit (ECC). Forty patients with Fontan operation (8 with APC Fontan, 22 with LT Fontan, and 10 with ECC Fontan) were enrolled. Velocity time integral (VTI) and average peak velocity (APV) were assessed according to cardiac and respiratory cycles in SVC, IVC, hepatic vein, conduit, LPA, and RPA using direct intravenous Doppler echocardiography. During each cardiac cycle in APC, VTI and APV between inspiration and expiration did not show significant differences in SVC, IVC, HV, LPA, or RPA. During each cardiac cycle in LT and ECC, VTI and APV between inspiration and expiration showed significant differences in all native vessels. The gap between S and D wave in APC was the highest, followed by that in LT. It was the lowest in ECC regardless of inspiration or expiration. Hepatic reverse VTI and APV in APC showed significant decreases compared to those in VC and PA during inspiration and expiration. Flow size and volume in APC were more influenced by cardiac cycle. Those in LT were moderately influenced by both respiratory cycle and cardiac cycle while those in ECC were more influenced by respiratory cycle. APC Fontan has hemodynamic inefficiency with prominent reverse flow. However, total cavopulmonary connection (TCPC) Fontan has more hemodynamic efficiency without prominent reverse flows.