Stroke prognosis and abnormal nocturnal blood pressure falls in older hypertensives

It remains uncertain whether abnormal dipping patterns of nocturnal blood p ressure influence the prognosis for stroke. We studied stroke events in 575 older Japanese patients with sustained hypertension determined by ambulato ry blood pressure monitoring (without medication). They were subclassified by their nocturnal systolic blood pressure fall (97 extreme-dippers, with g reater than or equal to 20% nocturnal systolic blood pressure fall; 230 dip pers, with greater than or equal to 10% but <20% fall; 185 nondippers, with <greater than or equal to>0% but <10% fall, and 63 reverse-dippers, with < 0% fall) and were followed prospectively for an average duration of 41 mont hs. Baseline brain magnetic resonance imaging (MRI) disclosed that the perc entages with multiple silent cerebral infarct were 53% in extreme-dippers, 29% in dippers, 41% in nondippers, and 49% in reverse-dippers. There was a J-shaped relationship between dipping status and stroke incidence (extreme- dippers, 12%; dippers, 6.1%; nondippers, 7.6%, and reverse-dippers, 22%), a nd this remained significant in a Cox regression analysis after controlling for age, gender, body mass index, 24-hour systolic blood pressure, and ant ihypertensive medication. Intracranial hemorrhage was more common in revers e-dippers (29% of strokes) than in other subgroups (7.7% of strokes, P=0.04 ). In the extreme-dipper group, 27% of strokes were ischemic strokes that O ccurred during sleep (versus 8.6% of strokes in the other 3 subgroups, P=0. 11). In conclusion, in older Japanese hypertensive patients, extreme dippin g of nocturnal blood pressure may be related to silent and clinical cerebra l ischemia through hypoperfusion during sleep or an exaggerated morning ris e of blood pressure, whereas reverse dipping may pose a risk for intracrani al hemorrhage.