Nocturnal Blood Pressure Dip in Stroke Survivors

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Abstract
Background and Purpose The influence of a nocturnal blood pressure dip on stroke recurrence has not yet been clarified. In this pilot study, we attempted to establish a correlation of the nocturnal blood pressure dip with stroke recurrence and development of new silent ischemic lesions in patients with chronic ischemic cerebrovascular disease. Methods We monitored circadian blood pressure patterns by use of a portable blood pressure monitoring device in 81 patients with chronic ischemic cerebrovascular disease and divided them into two subgroups according to levels of diurnal and nocturnal blood pressure (nocturnal blood pressure dippers and nondippers). The subgroups were prospectively followed up and compared for stroke recurrence and new silent ischemic lesions on magnetic resonance imaging. Results The average follow-up period was 27.2±11.3 months (mean±SD). Seventy-six patients completed the study; 43 (36 men and 7 women, aged 63.0±6.3 years) were being treated with antihypertensive agents and 33 (25 men and 8 women, aged 64.7±9.2 years) were not receiving treatment. In the treated group, recurrence was more frequent among the nocturnal dippers (5 of 18 patients, 12.5% per patient-year) than among the nondippers (1 of 25 patients, 1.5% per patient- year) ( P <.05). All subjects who developed a recurrent attack during sleep had had a nocturnal blood pressure dip pattern before the attack. Furthermore, the increase in symptomatic (recurrence) and/or asymptomatic (silent) brain lesions was more frequent in the nocturnal dippers than in the nondippers (9 of 14 versus 2 of 18, P <.01). In the nontreated group, no clear difference was found between the two subgroups. Conclusions This study indicated that the nocturnal blood pressure dip in patients treated with antihypertensive agents may accelerate the increase in ischemic brain lesions.