DEPENDENCY OF ARTERIAL COMPLIANCE ON CIRCULATING NEUROENDOCRINE AND METABOLIC FACTORS IN NORMAL SUBJECTS

Reduced arterial compliance is now recognized as a feature of hypertension. Similarly, metabolic factors such as insulin, catecholamines and lipids are also associated with hypertension. This study explores the possibility that these neuroendocrine and metabolic factors may separately influence arterial compliance. Proximal compliance (aorta and large arteries) and distal compliance (small arteries and arterioles) were measured in 57 volunteers (30 hypertensive and 27 normotensive subjects, mean age 45 years). Compliance was quantified by analysis of arterial pulse wave contours obtained intraarterially together with hemodynamic estimates. Proximal compliance correlated with plasma insulin (r = -0.49; p < 0.001), norepinephrine r = -0.50; p < 0.002), triglycerides (r = -0.39; p < 0.01), total cholesterol (r = -0.33; p = 0.02) and high-density lipoprotein cholesterol (HDL) (r = 0.37; p < 0.02). Similarly, distal compliance correlated with insulin (r = -0.37; p < 0.02), triglycerides (r = -0.39; p < 0.01), total cholesterol (r = -0.38; p < 0.01) and HDL (r = 0.51, p < 0.002). Patients with reduced compliance (<1.65 ml/mm Hg; n = 30), when compared with those with normal compliance (> 1.65 ml/mm Hg; n = 27), had higher levels of insulin (15 +/- 2 vs 10 +/- 1-mu-U/ml; p < 0.005), plasma renin activity (1.9 0.2 vs 1.5 +/- 0.2 ngAngl/ml/hour; p < 0.001), triglycerides (145 +/- 66 vs 108 +/- 51 mg/dl; p < 0.05), total cholesterol (229 +/- 47 vs 204 +/- 41 mg/dl; p < 0.05) and lower HDL levels (46.6 +/- 2.1 vs 51.1 +/- 2.0 mg/dl; p = 0.1). These findings suggest that such humoral factors as catecholamines, the renin system, lipids and insulin may be linked to the morphologic changes that decrease the compliance of the proximal and distal portions of the arterial circulation.