Relative influence of insulin resistance versus blood pressure on vascularchanges in longstanding hypertension. ICARUS, a LIFE sub study

Background Insulin resistance is associated with hypertension. The relative influences of hyperinsulinaemia and high blood pressure on vascular hypert rophy and carotid distensibility is unclear in patients with longstanding h ypertension. Methods In 88 unmedicated patients with stage II-III hypertension and left ventricular hypertrophy on electrocardiogram we measured blood pressure, mi nimal forearm vascular resistance (MFVR) using plethysmography, intima-medi a thickness (IMT) and the wall distensibility of the common carotid arterie s using ultrasound, and insulin sensitivity using a 2-h isoglycaemic hyperi nsulinaemic clamp. Results IMT was positively correlated to systolic blood pressure (r = 0.26, P < 0.05), whole body glucose uptake index (M/IG; r = 0.22, P < 0.05), age (r = 0.24, P < 0.05) and negatively correlated to body mass index (r = -0. 24, P < 0.05); IMT did not correlate to fasting serum insulin (r = -0.14, N S), In men (n = 64) MFVR was positively correlated to systolic blood pressu re (r = 0.30, P < 0.05), but was unrelated to M/G and serum insulin. The di stensibility of the common carotid arteries was negatively correlated to sy stolic blood pressure (r = -0.40, P < 0.001) and in untreated patients (n = 22) positively correlated to M/IG (r = 0.47, P < 0.05). Conclusions High systolic blood pressure was related to vascular hypertroph y, whereas hyperinsulinaemia and insulin resistance were not, suggesting th at longstanding high blood pressure is a far more important determinant for structural vascular changes than insulin resistance at this stage of the h ypertensive disease, However, hyperinsulinaemia and insulin resistance were associated with low distensibility of the common carotid arteries in the s ubgroup of never treated hypertensive patients. J Hypertens 2000, 18:75-81 (C) Lippincott Williams & Wilkins.