Endothelium-dependent vasodilation is impaired in apparently healthy subjects with a family history of myocardial infarction

OBJECTIVES: To investigate whether endothelial-dependent vasodilation is altered in healthy subjects with a family history of myocardial infarction. SETTING: Tertiary University Hospital SUBJECTS AND DESIGN: Fifty apparently healthy subjects selected from the general population were subjected to an evaluation of endothelial-dependent vasodilation (EDV) and endothelial-independent vasodilation (EIDV) by means of local infusion of methacholine (MCh, 2 and 4 microg/min) and sodium nitroprusside (SNP, 5 and 10 microg/min) with measurements of forearm blood flow with venous occlusion plethysmography. The occurrence of plaque and the intima-media thickness of the carotid arteries were determined by ultrasonography. RESULTS: Subjects reporting at least one parent suffering from myocardial infarction (n = 11) showed a significantly lower EDV than subjects without such a family history (21 +/- 3.7 vs. 26 +/- 6.7 ml/min/100 ml tissue at MCh 4 microg/min, P<0.05). EIDV was not significantly different between the groups (21 +/- 6.8 vs. 18 +/- 5.4 ml/min/100 ml tissue at SNP 10 microg/min). Age, sex distribution, body mass index, waist to hip ratio, blood pressure, lipids, fasting blood glucose, smoking habits and status of the carotid arteries were not significantly different between the groups. CONCLUSION: A family history of myocardial infarction was found to be associated with an impaired endothelial-dependent vasodilation in the forearm of apparently healthy subjects. The risk factor profile was not different from the control group, suggesting that genetic factors are responsible for the impaired endothelial-dependent vasodilation.