Blood viscosity, plasma adrenaline and pasting insulin in hypertensive patients with left ventricular hypertrophy - ICARUS, a LIFE substudy

We have seen relationships between whole blood viscosity (WBV) and componen ts of the metabolic cardiovascular syndrome in borderline hypertensive youn g men and suggested that sympathetic nervous system (SNS) activity may be a mediator. In the present study we aimed to test this hypothesis in establi shed hypertension and to investigate the relationship between WBV and cardi ac dimensions. Unmedicated patients (n = 42) with stage II-III hypertension and electrocardiographic left ventricular hypertrophy (LVH) underwent hype rinsulinemic isoglycemic glucose clamp to assess glucose disposal rate (GDR ) and echocardiographic studies. WBV, plasma catecholamines and insulin wer e measured in arterialized venous blood. WBV at high shear rate correlated with baseline plasma adrenaline (r = 0.33, p = 0.04) and fasting insulin (r = 0.34, p = 0.04) while there was a negative trend for GDR (r = -0.21, p = 0.2). WBV at low shear rate correlated with plasma adrenaline (r = 0.49, p = 0.002) and resting heart rate (r = 0.36, p = 0.02). WBV was higher in sm okers than in non-smokers (p = 0.02) and in males than in females (p = 0.02 ). Fasting insulin independently explained 12% of the variation in WBV at h igh shear, while baseline adrenaline independently explained 17% of the var iation in WBV at low shear. Systolic blood pressure explained 31% of the va riation in LV mass index. Thus, we demonstrate positive relationships betwe en blood viscosity versus plasma adrenaline and fasting insulin in hyperten sive patients with LVH. We suggest that adrenergic activity may increase he matocrit and viscosity and hence reduce insulin sensitivity.