ACUTE HEMODYNAMIC-CHANGES AFTER FONTAN OPERATION - AN EXPERIMENTAL-STUDY

Seven adult mongrel dogs with an average body weight of 11.3 kg were subjected to experimental Fontan operation in order to evaluate acute hemodynamic changes at the Fontan circulation. The Fontan circulation was established by occlusion of the tricuspid valve with tightening a purse-string suture which was placed around the valve under inflow occlusion and was passed through the anterior right atrial wall, and by connection with a 10 mm Gore-Tex graft between right atrium and pulmonary artery. When the Fontan circulation was established, aortic pressure and cardiac output (CO) decreased from 94.9 +/- 22.0 mmHg to 41.9 +/- 6.0 mmHg and 0.907 +/- 0.179 liter/min to 0.259 +/- 0.072 liter/min, respectively. There were no significant changes in heart rate and systemic vascular resistance between normal and the Fontan circulations. On the other hand, pulmonary vascular resistance (PVR) increased from 11.6 +/- 7.3 units in the normal circulation to 21.8 +/- 13.0 units in the Fontan circulation. From this study it was concluded that main changes in hemodynamic parameters immediately after establishing the Fontan circulation were marked decrease in systemic arterial pressure and CO, and an increase in PVR. Therefore, one should consider a possibility of an increase in the PVR to the critical level when the Fontan operation was applied to patients with pulmonary hypertension.