FISH OIL IMPROVES ENDOTHELIUM-DEPENDENT CORONARY VASODILATION IN HEART-TRANSPLANT RECIPIENTS

Objectives. The purpose of this study was to determine whether dietary fish oil supplementation enhances endothelium-mediated vasodilator responses in human heart transplant recipients, a group known to have coronary artery disease and endothelial dysfunction. Background. Omega-3 fatty acid supplementation has been shown to enhance endothelium-dependent coronary vasodilation in animal models of atherosclerosis. Methods. Endothelium-dependent vasodilator responses to intracoronary acetylcholine infusion and endothelium-independent responses to nitroglycerin were evaluated in heart transplant recipients who received a high dose of dietary supplementation with omega-3 fatty acids for 3 weeks (5 g of eicosapentaenoic acid plus docosahexaenoic acid/day, n = 7) and compared with responses in a group of matched heart transplant recipients who did not receive fish oil (control patients, n = 7). Acetylcholine was selectively infused into the midportion of the left anterior descending or left circumflex coronary artery, with the noninfused left coronary artery serving as a control vessel. Serial coronary angiograms were performed after infusion with increasing doses of acetylcholine (infused concentrations 10(-6) to 10(-3) Mol/liter) and after intracoronary nitroglycerin administration. Results. The patients treated with fish oil showed a normal vasodilator response to acetylcholine with 14 +/- 2.5% and 15 +/-7% vasodilation (vs. baseline diameter) at infused acetylcholine concentrations of 10(-5) and 10(-4) Mol/liter, respectively. In contrast, the control patients demonstrated vasoconstrictor responses (-1 +/- 1% and - 9 +/- 4%) to acetylcholine at these same doses (p < 0.05 and < 0.005, respectively, for treated vs. control patients). There were no differences in the response to nitroglycerin between the control and treated patients. Conclusions. Dietary supplementation with fish oil significantly alters endothelium-dependent coronary vasodilation in heart transplant recipients without alteration of the responses to endothelium-independent vasodilation. Whether this enhancement of endothelial function can beneficially alter the natural history of heart transplant atherosclerosis warrants further study.