May vitamin C supplementation be a useful tool to improve endothelial function after acute myocardial infarction ?

Objective: Impaired brachial flow-mediated dilation (FMD) persisting after acute myocardial infarction (AMI) may be associated with an adverse outcome. Since oxidative stress may be involved, we investigated whether an early antioxidant therapy may improve FMD of AMI patients. Design and Methods: Twenty-five AMI patients (20 males, age 516, 47% STEMI, 85% revascularized) underwent a randomized, double-blind, placebo (PL)-controlled study. FMD after 5minutes of forearm ischemia and endothelium-independent vasodilation to sublingual 25 ı`g glycerol trinitrate (GTN), were assessed within 72 h from admission (T0) by highresolution ultrasound images using a computerized edge detection system and expressed as the maximal percentage increase in arterial diameter. Then, patients were randomized to receive either oral VitC 500mg/day (n¼13) or PL (n¼12) for 40 days, in addition to an optimized treatment (antiplatelets, aˆ-blockers, statins and ACE-inhibitors). FMD and GTN measurements were repeated at days 20 (T20) and 40 (T40) after hospital discharge. Blood pressure, hs-CRP, adhesion molecules, LDL and HDL cholesterol and TG were measured at T0 and T40. Results: At T0, FMD was 2.30.3% in the whole population. At T20, FMD significantly increased from T0 in both groups (vitC 2.51.0 to 3.31.3%, p<0,05; PL 2.10.8 to 3.,21.2%, p<0,05) with no differences between PL and VitC. In contrast, at T40 FMD improved further with VitC to 4.71.5 %, p<0,05, while with PL it did not (2.91.2%; p¼ns). ANOVA comparison for FMD time-course showed a more pronounced increase in FMD with VitC group than with PL (p<0,05). T0 GTN response was 8.54.2% in the entire group. Vit C had no effect on GTN dilation. Blood pressure, hs-CRP, adhesion molecules, LDL-C and HDL-C and TG were essentially the same between groups at both T0 and T40. Conclusion: The present data show a clear beneficial effect of a low-dose VitC supplementation on FMD of AMI patients, independently of a background optimal treatment. Therefore, an early antioxidant therapy with VitC may be useful in AMI patients. e12 Journal of Hypertension Vol 28, e-Supplement A, June 2010