PROGNOSTIC VALUE OF AMBULATORY BLOOD-PRESSURE MONITORING IN REFRACTORY HYPERTENSION - A PROSPECTIVE-STUDY

The objective of this study was to establish whether ambulator blood p ressure offers a better estimate of cardiovascular risk than does its clinical blood pressure counterpart in refractory hypertension, This p rospective study assessed tile incidence or cardiovascular events over time during an average follow-up oi 49, months (range, 6 to 96), Pati ents were referred to specialized hypertension clinics (86 essential h ypertension patients who had diastolic blood pressure >100 mm Hg durin g antihypertensive treatment that included three or more antihypertens ive drugs, one being a diuretic), Twenty-four-hour ambulatory blood pr essure monitoring (ABPM) was performed at the time of entrance. End-or gan damage was monitored yearly, and thr incidence of cardiovascular e vents was recorded, Patients were divided into tertiles of average dia stolic blood pressure during activity according to the ABPM, with the lowest tertile <88 mm Hg (LT, n=29), the middle tertile 88 to 97 mm Hg (MT, n=29), and the highest tertile >97 mm Hg (HT, n=28). While signi ficant differences in systolic and diastolic ambulatory blood pressure s were observed among groups, no differences were observed at either t he beginning or at the time of the last evaluation for office blood pr essure. During the last evaluation, a progression in the end-organ dam age score was observed the the HT group but not for the two Other grou ps. Twenty-one of the patients had a new cardiovascular event; the inc idence of events was significantly lower for the LT group (2.2 per 100 patient-years) than it was for the MT group (9.5 per 100 patient-year s) or for the HT group (13.6 per 100 patient-years). The probability o f event-free survival was also significantly different when comparing the LT group with the other two groups (LT versus MT log-rank, P<.04; LT versus HT log-rank, P<.006). The HT group was an independent risk f actor for the incidence of cardiovascular events (relative risk, 6.20: 95%; confidence interval, 1.38 to 28.1, P<.02), Higher values of ambu latory blood pressure result in a worse prognosis in patients with ref ractory hypertension, supporting the recommendation that ABPM is usefu l in stratifying the cardiovascular risk in patients with refractory h ypertension.