Effects of dilutional and modified ultrafiltration in plasma endothelin-1 and pulmonary vascular resistance after the Fontan procedure

Background. Pulmonary vascular resistance (PVR) is closely related with patients’ hemodynamics after the Fontan procedure and endothelin-1 (ET-1) may play an important role in pulmonary circulation. Modified ultrafiltration (MUF) is known to remove inflammatory mediators after cardiopulmonary bypass (CPB) surgery. The time courses of plasma ET-1 and PVR were examined before and after the Fontan procedure with MUF. Methods. Twenty-two patients who underwent the Fontan procedure were divided into two groups: a dilutional ultrafiltration/modified ultrafiltration (DUF/MUF) group (n =11) and a control group (n = 11). Conventional ultrafiltration was performed during CPB in the control group. DUF was performed semicontinuously during CPB and MUF was continued until 15 to 20 minutes after the CPB with polyacrylonitonile membrane in the DUF/MUF group. The plasma ET-1 concentration was mea-sured before and after CPB, after MUF in the DUF/MUF group, and 6 and 24 hours after CPB. PVR was calculated simultaneously using a thermodilutional catheter. Results. Plasma ET-1 levels increased significantly after CPB in the control group but they did not increase immediately after CPB in the DUF/MUF group. Similarly, PVR increased significantly after CPB in the control group but it did not increase after CPB in the DUF/MUF group and remained low at 6 and 24 hours after CPB. Conclusions. DUF and MUF suppress the increase in the plasma ET-1 concentration that occurs immediately after the completion of the Fontan procedure and may be an effective intervention for maintaining low PVR after the procedure