Reduced myocardial flow reserve relates to increased carotid intima-media thickness in healthy young men

Increased carotid artery wall thickness and lipoprotein oxidation are key e arly events in atherosclerosis. To test the hypothesis that reduced myocard ial flow reserve is a marker of subclinical atherosclerosis, we examined th e relationships between flow reserve and carotid artery intima-media thickn ess (IMT) in young men free from coronary heart disease. Basal and dipyrida mole stimulated coronary blood flow was measured using positron emission to mography (PET) in 55 healthy men aged 36 +/- 4 years. Myocardial flow reser ve was calculated as the ratio of stimulated Bow to basal flow. The mean ca rotid artery IMT was measured using high-resolution ultrasound. Oxidised LD L was measured as baseline LDL diene conjugation. Myocardial flow reserve d ecreased across the quartiles of increasing IMT (P = 0.006), and was 5.2 +/ - 1.9 in the lowest quartile for IMT and 3.7 +/- 1.2 in the highest (P = 0. 04, I vs. IV quartile). In univariate analysis, oxidised LDL correlated inv ersely with flow reserve (r = -0.35, P = 0.01) and directly with IMT (r = 0 .51, P < 0.001). The association between flow reserve and IMT remained sign ificant (P less than or equal to 0.01) in multivariate regression model inc luding age, blood pressure, left ventricular mass, ox-LDL, total cholestero l, HDL-cholesterol and triglycerides as covariates. These data support the concept that reduced myocardial flow reserve reflects subclinical atheroscl erosis in asymptomatic subjects, and suggest that increased lipoprotein oxi dation is directly related to early structural and functional atherosclerot ic vascular changes. (C) 2001 Elsevier Science Ireland Ltd. All rights rese rved.