COMPLEMENT ACTIVATION AND CYTOKINE GENERATION AFTER MODIFIED FONTAN PROCEDURE

Bnckground. The modified Fontan procedure separates the systemic and p ulmonary circulations in patients born with a functional single ventri cle. Delayed recovery is frequently observed after this procedure. It was our hypothesis that complement activation or cytokine generation m ay contribute to the pathophysiology of this problem. Methods. We meas ured activated complement C3, thromboxane B-2, interleukin-6, and tumo r necrosis factor-alpha levels by immunoassay in 16 patients undergoin g Fontan procedure. Patient plasma samples were obtained preoperativel y, on initiation of cardiopulmonary bypass, after administration of pr otamine, and 1, 4, 8, and 24 hours postoperatively. Results. There was no early or late mortality in this cohort of patients. Low cardiac ou tput developed in 3 of 16 patients, and pleural effusions developed in 5. The median length of hospital stay was 9 days. Activated complemen t C3 levels increased from a baseline of 1,486 +/- 564 to 4,600 +/- 45 4 ng/mL after cardiopulmonary bypass and administration of protamine, and returned to baseline by 24 hours. The level of interleukin-6 incre ased from 42 +/- 32 to 176 +/- 22 pg/mL and at 24 hours remained eleva ted at 71 +/- 15 pg/mL. Neither thromboxane B-2 nor tumor necrosis fac tor-alpha levels increased significantly. Conclusions. The data demons trate threefold to fourfold increases in activated complement C3 and i nterleukin-6, indicating that both humoral and cellular systems are af fected. It is our conclusion that complement and cytokine activation m ay contribute to the delayed recovery observed after Fontan procedure. (C) 1998 by The Society of Thoracic Surgeons.