Clinic-daytime blood pressure difference and cardiovascular damage

Objective To investigate whether the clinic-daytime blood pressure differen ce can provide information on vascular reactivity to stress comparable to t hat of simple noninvasive stimuli such as a cold presser test and isometric exercise, and whether there is any relationship between this blood pressur e difference and noninvasive measurements of the left ventricular mass and carotid arterial wall. Design Patients with newly discovered, never-treated, sustained hypertensio n were included in the study after a 1 month run-in, during which time thei r blood pressure was measured three times at 2 week intervals. Methods Blood pressure was measured by a noninvasive procedure at rest and during a cold presser test and an isometric exercise. The difference was ca lculated for systolic, diastolic and mean blood pressure as resting minus d aytime ambulatory blood pressure. Parameters of the posterior wall and sept al thickness of the left ventricle, aortic root and left atrium were studie d by M-mode echocardiography. Carotid wall thickness and diameter were meas ured using ultrasound. Results The 90 patients enrolled in the study were divided into tertiles of clinic-daytime blood pressure difference. The composition of the groups di ffered in sex, since the majority of women were in the highest tertile, but was comparable for age, body mass index, renin-aldosterone axis and lipid and carbohydrate metabolism. Blood pressure responses to cold and isometric exercise were more pronounced in patients in the lowest tertile of blood p ressure difference. No intergroup differences were detected in echocardiogr aphic parameters of ventricular (left ventricular mass, tertiles I-III: 46. 5 +/- 10, 42.3 +/- 8, 44.8 +/- 13 g/m(2.7), respectively) and carotid (inti ma-media thickness, tertiles I-III 0.58 +/- 0.1, 0.54 +/- 0.1, 0.62 +/- 0.1 mm, respectively) structure. Conclusions The present study indicates that the clinic-daytime blood press ure difference provides different information on cardiovascular reactivity compared with that obtained from the cold presser test and isometric exerci se. Moreover, it does not seem to have any relationship with ventricular hy pertrophy and/or carotid wall thickening. J Hypertens 1999, 17:331-337 (C) Lippincott Williams & Wilkins.