Association between insulin resistance and reduced coronary vasoreactivity in healthy subjects

BACKGROUND: Insulin resistance appears to be an important risk factor for coronary artery disease. OBJECTIVE: To examine the role of insulin resistance on coronary vasoreactivity in healthy subjects. PATIENTS AND METHODS: Myocardial blood flow was quantitated using positron emission tomography and oxygen, 15-labelled water in 10 healthy, nonobese men. The perfusion measurements were performed basally and during adenosine infusion, which has been used as a measure of coronary vasoreactivity. After per-fusion measurements were taken, whole-body glucose uptake was determined using the euglycemic hyperinsulinemic clamp technique. RESULTS: Basal myocardial blood flow was 0.89 +/- 0.21 ml(.)g(-1.)min(-1) adenosine significantly increased the flow to 4.00 +/- 1.13 mL(.)g (-1.)min(-1). Adenosine-stimulated myocardial blood flow was inversely associated with fasting serum insulin concentration (r=-0.69, P<0.05). Concordantly, hyperemic blood flow was associated with whole-body glucose uptake during euglycemic hyperinsulinemic conditions (r=0.64, P<0.05). Basal myocardial blood flow was not affected by insulin resistance. CONCLUSION: The results of the present study demonstrate the novel finding that insulin resistance is associated with reduced coronary vasoreactivity, even in healthy subjects.