Effect of vitamin C on endothelium-dependent vasodilation in patients with coronary heart disease after a high-fat meal

Objective To evaluate the effect of a single oral dose of vitamin C on postprandially impaired endothelium dependent vasodilatation in patients with coronary heart disease (CHD) after a single high fat meal. Methods Seventy four patients with CHD were randomly divided into two groups. Patients in group A ( n =37) accepted 2 grams of vitamin C, whereas in group B ( n =37) did not treated with vitamin C after a high fat meal. The serum levels of triglyceride, total cholesterol, low density lipoprotein cholesterol and high density lipoprotein cholesterol in fasting and at 2, 4, 5, 7 hours after the high fat meal were measured. Endothelium dependent vasodilatation (flow mediated vasodilatation) and endothelium independent vasodilatation (nitroglycerin induced vasodilatation)was assessed in the brachial artery by high resolution ultrasound technique before eating and at 4 hours postprandially. Results The fasting endothelium dependent vasodilatations were impaired in CHD patients. The postprandial serum triglyceride concentration increased significantly at 2-7 hours after the high fat meal in all subjects. The impaired endothelium dependent vasodilatation restored [(3.63±0.59)% vs (4.51±0.49)%, P =0 064] in Group A, but significantly aggravated [(3.58±0.63)% vs (0.58±0.40)%, P 0.001] in Group B. The postprandial endothelium independent vasodilatation has no obvious change in the two groups compared with that in the fasting state [Group A:(19.48±1.38)% vs(20.25±1.21)%, P =0.498;Group B:(18.71± 1.53)% vs(16.36±1.53)%, P =0.135]. The decrement of postprandial flow mediated vasodilatation positively correlated with the increment of 2 hour serum TG concentration ( r =0.395, P 0.02). Conclusion The impaired endothelium dependent vasodilatation aggravated in CHD patients after a high fat meal, and vitamin C treatment has a promising benefit to CHD patients.