The clinical prognostic significance of white coat hypertension (WCH) is still controversial. Although recent longitudinal studies have provided preliminary prognostic data on subjects with WCH as compared to patients with sustained hypertension, the possible relation between WCH and vascular risk is still under debate. The purpose ot this study was to compare the circadian pattern of blood pressure (BP) variability between normotensive abd WCH subjects. We studied 917 subjects (495 men and 422 women), 49.5±14.5 (mean±SD) years of age, with diurnal BP mean below 135/85 for systolic/diastolic BP, and hyperbaric index (area of BP excess above a time-specified tolerance interval) below the previously established threshold for diagnosis of hypertension from data obtained by ambulatory BP monitoring [Hypertension. 2000;35:118–125]. Among those subjects, 407 (235 men and 172 women) were diagnosed with WCH (mean from 6 office BP measurements above 140 or 90 mm Hg for systolic or diastolic BP). BP was measured at 20-min intervals from 07:00 to 23:00 hours and at 30-min intervals at night for 48 consecutive hours. Circadian parameters established by population multiple-component analysis [Chronobiol Int. 1998;15:191–204] were compared between normotensive and WCH subjects by nonparametric testing. Patients with WCH are characterized by a significant increase in systolic (3.4 mm Hg; P<0.001) but not in diastolic BP (−0.4 mm Hg, P=0.238 for comparison of 24-hour mean) as compared to normotensive subjects. Although more pronounced during the diurnally active hours, the differences in systolic BP between normotension and WCH were significant throughout the 24 hours of the day. The largest and most significant difference between groups was found around the clock in pulse pressure (3.8 mm Hg in 24-hour mean, P<0.001). In volunteers studied by 48-hour ambulatory monitoring, WCH is characterized by a significant elevation in systolic BP and, especially, in pulse pressure as compared to normotensive subjects. Increased pulse pressure is an independent marker of cardiovascular risk, mainly for myocardial infarction, congestive heart failure, and cardiovascular deaths. Accordingly, WCH could be associated to a long-term worst prognosis in comparison to true normotension, an issue that deserves further prospective investigation. Am J Hypertens (2004) 17, 41A–42A; doi: 10.1016/j.amjhyper.2004.03.099
Discussion(0)
No comments yet. Be the first to comment.