DIURNAL BLOOD-PRESSURE CHANGE VARIES WITH STROKE SUBTYPE IN THE ACUTE-PHASE

Background and Purpose-It is unclear whether acute stroke is associate d with a loss of the normal diurnal blood pressure (BP) change and whe ther stroke type influences this. Some of this confusion results from the use of fixed time definitions of day and night, which can be overc ome by the use of cumulative sums analysis (cusums). Methods-Ninety-ei ght stroke patients had 24-hour BP monitoring (Spacelabs 90207) perfor med within 48 hours of ictus. Three subgroups were identified: cortica l infarct, n=50; subcortical infarct, n=29; and primary intracerebral hemorrhage [PICH], n= 19. An age-matched control group of 74 subjects was also studied. Diurnal change was assessed by both day-night differ ences (absolute and percentage) and cusums (cusums plot height [CPH] a nd circadian alteration magnitude [CDCAM]); ANCOVA was used to compare groups. Results-Compared with control subjects, cortical infarct and PICH subgroups had significantly reduced mean diurnal systolic changes using day-night differences (absolute, -12 and -17 mm Hg; percentage, -10 and -12, respectively; P<0.0001) and cusums (CDCAM, -6.96 and -8. 6 mm Hg; CPH, -32.05 and -46.04 mm Hg, respectively; P<0.005), only th e subcortical infarct subgroup demonstrated reduced percentage differe nces (-4.4%, P<0.02). Mean diastolic differences were significantly re duced in all stroke subgroups(CPH, -24.84, -17.31, and -36.92 mm Hg; a bsolute, -8.26, -4.04, and -11.44 mm Hg; percentage, -10.65, -5.81, an d -15.23%, for cortical infarct, subcortical infarct, and PICH subgrou ps, respectively; P<0.05), except for CDCAM, which was not reduced in subcortical infarcts (-4.78 and -7.70 mm Hg for cortical infarct and P ICH subgroups, respectively; P<0.001). Conclusions-Diurnal BP change w as reduced in the 3 stroke subgroups studied, especially in patients w ith cortical infarcts and PICH. This may reflect damage to the central modulation of autonomic BP control. The implications in terms of prog nosis and therapy in the acute period require further study.