BACKGROUND: We hypothesized that the decreased nitric oxide after cardiopulmonary bypass and reperfusion would play an important role in temporary pulmonary hypertension.
METHODS: We used the pulmonary arteries of three pigs weighing 40-50 kg after cardiopulmonary bypass and reperfusion in experimental group. We also used the pulmonary arteries of five pigs before cardiopulmonary bypass under sham operation in control group. All cumulative concentration-effect curves were performed on vessel rings beginning at their optimum resting zone. EC50 and maximal response (Emax) were calculated by using nonlineal logistic regression analysis with the software PRISM (Graphpad, Mountain View, CA).
RESULTS: CPB inhibited endothelium-dependent relaxation to acetylcholine in pulmonary arterial rings, but did not affect SNP induced relaxation in ones.
CONCLUSIONS: The Ability of pulmonary arterial relaxation after CPB and reperfusion in pigs was decreased without attenuated pulmonary arterial sensitivity to NO.