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Selective endothelial dysfunction in conscious dogs after cardiopulmonary bypass
P Zanaboni1, P A Murray, B A Simon
1Department of Anesthesiology and Critical Care Medicine, Johns Hopkins Medical Institutions, Baltimore, Maryland 21287-8711, USA.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|June 1, 1997
Summary
Cardiopulmonary bypass (CPB) impairs acetylcholine-induced pulmonary vasodilation, suggesting a selective endothelial defect. However, responses to bradykinin and sodium nitroprusside remain unaffected post-CPB.
Area of Science:
- Cardiovascular Physiology
- Pulmonary Circulation
- Endothelial Function
Background:
- Cardiopulmonary bypass (CPB) is known to cause prolonged pulmonary vascular hyperreactivity.
- Understanding the specific effects of CPB on pulmonary vasodilation is crucial for patient recovery.
Purpose of the Study:
- To investigate the impact of CPB on endothelium-dependent and independent pulmonary vasodilation.
- To determine if CPB selectively affects specific vasodilator pathways in the pulmonary vasculature.
Main Methods:
- Conscious dogs underwent continuous left pulmonary vascular pressure-flow (LP-Q) plotting before and 3-4 days after CPB.
- Pulmonary vasodilation was assessed using acetylcholine, bradykinin, and sodium nitroprusside following preconstriction with U-46619.
Main Results:
- The dose of U-46619 required for preconstriction was lower post-CPB.
- Acetylcholine's pulmonary vasodilator response was completely abolished post-CPB.
- Responses to bradykinin and sodium nitroprusside were not significantly altered after CPB.
Conclusions:
- CPB induces a selective defect in endothelial-dependent vasodilation mediated by acetylcholine.
- The findings suggest a specific impairment in the acetylcholine pathway, not a general endothelial dysfunction.
- cGMP-mediated vasodilation, as indicated by the sodium nitroprusside response, remains intact post-CPB.