INSULIN-RESISTANCE AND HYPERLIPOPROTEINEMIA IN MICROVASCULAR ANGINA -RISK-FACTORS OR PATHOGENETIC LINK

Background: Patients with chest pain and normal epicardial coronary ar teries (microvascular angina; syndrome X) are characterized by an impa irment of myocardial perfusion reserve which may be related to functio nal and morphological abnormalities of the intramyocardial arterioles. Methods: In an attempt to identify predisposing factors for microvasc ular angina we investigated 34 consecutive patients (15 female, 19 mal e; mean age 53 +/- 7 years) with microvascular angina but without hype rtension or left ventricular hypertrophy. The metabolic profile, inclu ding plasma insulin, glucose, cholesterol, low-density lipoprotein cho lesterol, triglycerides, very-low-density lipoprotein cholesterol and fibrinogen levels, was determined in each case. Furthermore, insulin a nd glucose levels were measured after an oral glucose load of 100 g ov er 3 h. All parameters were compared with those of a control group of 15 healthy subjects matched for age, sex and body mass index. Results: The systolic blood pressure in microvascular angina was 137 +/- 17 mm Hg and thus higher than that of healthy controls (124 +/- 11 mmHg); di astolic blood pressure was 85 +/- 7 compared with 78 +/- 9 mmHg in con trols. Insulin level was significantly elevated in patients with micro vascular angina 90 min (median: 101 versus 54 mu U/ml) and 120 min (me dian: 88 versus 51 mu U/ml) after ingestion of 100 g glucose. The fast ing glucose level was 98 +/- 12 versus 87 +/- 7 mg/dl in controls. Glu cose concentration was also elevated after 30 min (176 +/- 28 versus 1 48 +/- 32 mg/dl), after 45 min (198 +/- 35 versus 152 +/- 53 mg/dl) an d after 60 min (193 +/- 44 versus 145 +/- 54 mg/dl). In microvascular angina, parameters such as total cholesterol (244 +/- 46 versus 199 +/ - 29 mg/dl), low-density lipoprotein cholesterol (157 +/- 41 versus 12 2 +/- 18 mg/dl) and fibrinogen (377 +/- 150 versus 285 +/- 69 mg/dl) w ere elevated. Conclusions: The metabolic profile in patients with micr ovascular angina suggests a pathogenetic role of insulin resistance an d hyperlipoproteinemia in the setting of impaired myocardial coronary reserve and in early stages of hypertensive heart disease.