There are many reports about white coat hypertension (WCH), still the clinical significance and pathophysiology of WCH is ambiguous. The aim of this study was to find out the difference of RAAS activity in WCH compared with the essential hypertension (EH) group, which could suggest the role of RAAS activity in the development of WCH.Design and Method:
Never treated hypertension patients who visited 8 hospitals of The Catholic University of Korea from January 2011 through July 2012 were enrolled. WCH was defined as high office blood pressure (BP) (>140/90 mmHg), but normal blood pressure measured by day time ambulatory blood pressure monitoring (ABPM) (<135/85 mmHg). Of the 869 never treated patients with high office BP, 146 (age 47 ± 11) patients who underwent ABPM and examined plasma renin activity (PRA) and plasma aldosterone level (PAL) were identified. PAL/PRA ratio (ARR) was calculated and patients with the possibility of primary aldosteronism (ARR > 27 ng/dl per ng/ml/hr) were excluded. Among the patients, one hundred eighteen patients were diagnosed with EH (age 47 ± 10), and eighteen patients were diagnosed with WCH (age 47 ± 15). The PRA, PAL, and ARR in patients with WCH were compared with the EH group.Results:
There were no significant differences with age and other cardiovascular risk factors.(Table 1.) Although, PRA [(2.1 ± 1.3 ng/ml/hr) in WCH, (1.7 ± 1.4 ng/ml/hr) in EH, p = 0.20] and PAL [(12.5 ± 6.5 ng/dL) in WCH, (10.6 ± 8.4 ng/dL) in EH, p = 0.37] did not show a significant difference between the two groups, ARR was significantly lower in patients with WCH (6.7 ± 3.1) compared to the EH group. (8.7 ± 6.5, p = 0.04).Conclusions:
ARR is significantly low in WCH compared to EH. Since ARR reflects aldosterone activity and target organ damage in especially hypertensives, high ARR may play a role in progression from WCH to EH.