Effect of chinese herbal medicine for calming Gan (肝) and suppressing hyperactive yang on arterial elasticity function and circadian rhythm of blood pressure in patients with essential hypertension

Objective To observe the effect of Chinese herbal medicine for calming Gan (肝) and suppressing hyperactive yang (平肝潜阳, CGSHY) on arterial elasticity function and the circadian rhythm of blood pressure in patients with essential hypertension (EH). Methods Adopting a parallel, randomized design, sixty-four patients with EH of stages I and II were randomly divided into two groups according to a random number table, with 32 in each group. The patients in the treatment group were treated with CGSHY and those in the control group were treated with Enalapril. All patients were given 24-h ambulatory blood pressure monitoring (ABPM) before and after a 12-week treatment. Trough/peak (T/P) ratios of systolic and diastolic blood pressure (SBP & DBP) of each group were calculated. The circadian rhythm of their blood pressure was observed at the same time. The changes in elasticity of the carotid artery in the patients, including stiffness parameter (β), pressure-strain elastic modulus (Ep), arterial compliance (AC), augmentation index (AI), and pulse wave velocity (PVWβ) were determined by the echo-tracking technique before and after a 12-week treatment. In the meantime, their levels of nitric oxide (NO) and endothelin-1 (ET-1) were measured respectively. Results After treatment, all parameters in the 24-h ABPM and the elasticity of the carotid artery (β, Ep, AC and PVWβ) were markedly improved, the level of NO was increased, and ET-1 was decreased in both groups as compared with values before treatment (P<0.05 or P<0.01). Further, the improvements in the ratio of T/P of SBP & DBP and in the level of NO and ET-1 in the treatment group were more signifificant than those in the control group (P<0.05). There were no signifificant differences in all parameters in the ABPM monitoring and the elasticity of the carotid artery, the recovery of blood pressure circadian rhythm, and the therapeutic effect of antihypertension in EH patients between the two groups (P>0.05). Conclusions Chinese herbal medicine for CGSHY may lower the blood pressure smoothly and recover the circadian rhythm of blood pressure in EH patients. They may also improve the carotid elasticity of EH patients similar to that of Enalapril. The mechanism of action of Chinese herbs on EH might be related to the regulation of vascular endothelium function.