Circadian rhythm of blood pressure and the association of rennin-angiotensin system and target organ damage

Objective:To investigate circadian rhythm of blood pressure and the association of rennin-angiotensin system and target organ damage in hypertensive patients. Methods:The study covered 242 hypertensives which were divided into two groups according to the results of ambulatory blood pressure monitoring (ABPM),dipper group (n=96) and non-dipper group (n=146). The levels of plasma renin,angiotensin Ⅱ and aldosterone were tested with radioimmunoassay after overnight recumbency and upright posture in all patients. Target organ damage was assessed by echocardiogram and renal function. Results:(1) There were no significant differences in 24 hSBP,24 hDBP,dSBP,dDBP between the dipper group and the non-dipper group,but the levels of nSBP,nDBP and 24 hHR in the non-dipper group were higher than those in dipper group (P0.05). (2) The level of angiotensin Ⅱ after overnight recumbency was higher in the non-dipper group than in dipper group (P0.05). No significant differences were found between two groups in terms of blood sodium and blood potassium. (3) The LVEDd,LVMI and the level of creatinine were higher in the non-dipper group than in the dipper group (P0.05). Conclusion:Renin-angiotensin system plays an important role in the regulation of circadian rhythm of blood pressure,the damage in target organs such as heart and kidney in the hypertensives with non-dipper distribution was more serious than in those with dipper one.