Background: Ambulatory blood pressure may be higher or lower than clinic blood pressure. Attention has focused on "white coat hypertension" (normal ambulatory blood pressure elevated in the clinic). The converse phenomenon of high ambulatory blood pressure but normal office blood pressure-"white coat normotension"-has not been studied.
Objective: To assess whether white coat normotension (awake ambulatory blood pressure > 134/90 mm Hg and clinic blood pressure < 140/90 mm Hg) is associated with target organ damage.
Design: Cross-sectional observational study.
Setting: University hospital hypertension center and participant work sites.
Patients: 295 clinically normotensive adults and 64 patients with sustained hypertension (elevated clinic and ambulatory blood pressure).
Measurements: Target organ abnormalities were measured by echocardiography and arterial ultrasonography in 61 patients with white coat normotension, 234 with sustained normotension (normal clinic and ambulatory blood pressure), and 64 with sustained hypertension.
Results: Patients with white coat normotension were older; had higher body mass indices, serum creatinine concentrations, and glucose levels; and a higher prevalence of current smokers. Left ventricular mass index and relative wall thickness were higher by 13 g/m2 (CI, 8 to 18 g/m2) and by 0.03 (CI, 0.01 to 0.04), respectively, in patients with white coat normotension compared with those who had sustained normotension. Patients with white coat normotension and those with sustained hypertension did not differ significantly for left ventricular mass index (4 g/m2 [CI, - 3 to 10 g/m2) or relative wall thickness (0.01 [CI, -0.01 to 0.03]). The prevalence of discrete atherosclerotic plaques was similar in patients with white coat normotension (17 of 61, or 28% [CI, 17% to 39%]) and those with sustained hypertension (17 of 64, or 27% [CI, 16% to 38%]), but the difference lost significance after adjustment for age.
Conclusions: White coat normotension is associated with left ventricular mass and carotid wall thickness similar to those in sustained hypertension. The association of white coat normotension with prognostically important target organ damage may partly explain the ability of high normal left ventricular mass and high normal clinic blood pressure to predict subsequent hypertension and cardiovascular events in patients with clinical normotension.