Increased plasma levels of endothelin-1 after cardiopulmonary bypass in patients with pulmonary hypertension and congenital heart disease.
The plasma level of the potent vasoconstrictor endothelin-1 was measured in children who underwent cardiac operations. Forty-five patients were divided into two groups, those with a high pulmonary blood flow (HF group; n = 23) and those with a normal or low flow (NF group; n = 22). Seven blood samples were taken: immediately before cardiopulmonary bypass, immediately after removing the aortic cross-clamps, immediately after discontinuing bypass, and at 20 minutes and 3, 6, and 24 hours after termination of bypass. The plasma levels of endothelin-1 were similar in both groups before bypass. From the time the aortic crossclamps were removed, the plasma endothelin-1 levels in both groups increased significantly, to reach a peak level at 3 to 6 hours. The increase was significantly greater in the HF than in the NF group, and the maximum values in the two groups were 12.6 +/- 1.1 and 9.6 +/- 0.8 fmol/ml, respectively (mean +/- standard error of the mean, p < 0.05). The value 20 minutes after bypass showed a positive correlation with the mean pulmonary arterial pressure measured at the preoperative cardiac catheterization study (r = 0.41, p < 0.05). In addition, a significant positive correlation was obtained between endothelin-1 3 hours after bypass and the maximum pulmonary/systemic arterial pressure ratio during the first 12 hours after operation (r = 0.86, p < 0.05). These results suggest that cardiopulmonary bypass is associated with an immediate postoperative increase in circulating endothelin and that patients who had a high pulmonary blood flow before the operation are particularly vulnerable, bypass having a more injurious effect on a lung with preexisting endothelial dysfunction. A high level of circulating endothelin may predispose to pulmonary vascular lability and pulmonary hypertensive crises in the postoperative period.
Komai
H
H
Vascular Biology and Pharmacology Unit, Institute of Child Health, London, England.
Adatia
I T
IT
Elliott
M J
MJ
de Leval
M R
MR
Haworth
S G
SG
D000293:Adolescent; D001783:Blood Flow Velocity; D001794:Blood Pressure; D006348:Cardiac Surgical Procedures; D002315:Cardiopulmonary Bypass; D002648:Child; D002675:Child, Preschool; D016232:Endothelins / Q000097:blood*; D005260:Female; D006330:Heart Defects, Congenital / Q000097:blood* / Q000150:complications / Q000601:surgery*; D006801:Humans; D006976:Hypertension, Pulmonary / Q000097:blood* / Q000209:etiology / Q000503:physiopathology; D007223:Infant; D008297:Male; D011651:Pulmonary Artery / Q000503:physiopathology; D011652:Pulmonary Circulation
D016232:Endothelins