Association of lower nighttime diastolic blood pressure and hypoxia with silent myocardial injury: The Japan Morning Surge‐Home Blood Pressure study

Abstract

Elevated blood pressure (BP), when assessed by not only conventional office BP but also out-of-office BP measurements, such as ambulatory BP monitoring (ABPM), has been well acknowledged to be a cardiovascular disease (CVD) risk. 1-4 In particular, elevated nighttime BP as assessed by ABPM has been associated with myocardial overload and has been shown to have more prognostic power than daytime BP. 5-13 On the other hand, excessive nighttime BP reduction may also be a CVD risk. Previous studies reported that marked nocturnal BP fall, that is, extreme-dipping, was associated with a risk of cerebral and myocardial ischemia, 14-18 but this issue is still controversial. Nighttime hypoxia induced by sleep-disordered breathing (SDB) has also been revealed to confer a risk of CVD events. 19-21 Various