Evolution of blood pressure and cholesterol in stage 1 hypertension: role of autonomic nervous system activity

OBJECTIVE: Controversy remains concerning the pathogenetic mechanisms for the relationship between sympathetic activity, hypertension and lipid abnormalities. We tested the hypothesis that a condition characterized by sympathetic predominance may affect the evolution of blood pressure and lipids in the early stage of hypertension. METHODS: We prospectively studied 163 young stage 1 hypertensive individuals and 28 normotensive control individuals. The hypertensive subjects were divided by cluster analysis into two groups according to low frequency and high frequency components of heart rate variability. Large artery and small artery compliance was assessed at the end of the follow-up. RESULTS: Fifty-nine subjects showed reduced total power and signs of sympathetic predominance in the resting condition, on standing and during mental stress (group 1). At baseline, they had similar blood pressure and metabolic data to the rest of the group (n = 104, group 2) and a greater white-coat effect (P = 0.03). During a 6-year follow-up, 23.7% of group 1 subjects versus 9.6% of group 2 subjects developed sustained hypertension requiring antihypertensive treatment (P = 0.02). In group 1 subjects, there was also a greater increase in total cholesterol (P = 0.01) than in group 2. In addition, at the end of follow-up group 1 subjects had impaired large artery compliance (P < 0.001 versus group 2). CONCLUSIONS: These data indicate that a condition characterized by sympathetic predominance may favour the development of sustained hypertension and hypercholesterolemia early in life, and lead to increased susceptibility to vascular complications. They further indicate that the increased white-coat effect is not an innocent phenomenon.