New Technology and Evidence
The issues of hypertension paradox—more uncontrolled disease despite improved therapy—have received increased attention in the era of strict blood pressure (BP) control after SPRINT (Systolic Blood Pressure Intervention Trial) in 2015.1 The new direction in the management of hypertension is to pursue earlier and lower BP control throughout 24 hours.2 The new 2017 American College of Cardiology (ACC)/American Heart Association (AHA) guidelines propose that all the BPs measured during the awake period (clinic BP and home BP measured in the morning and evening) and daytime ambulatory BPs should be controlled to <130/80 mm Hg as a universal BP goal.3 Even if the clinic BP is well-controlled, masked morning and daytime hypertension (uncontrolled daytime and morning or evening home BPs) pose an increased risk of cardiovascular diseases.4–10 The strict BP control of all these awake BPs would be effective for the reduction of cardiovascular events.
However, even after controlling these daytime BPs, there is still a residual risk in the management of hypertension. This is masked uncontrolled nocturnal hypertension. Here, I summarize the clinical implications of the control of night-time BP based on the pathophysiology and recent evidence and present up-to-date information on the research and development of night-time home BP monitoring (HBPM) systems.
The pattern of circadian rhythm of BP can be evaluated by ambulatory BP monitoring (ABPM). In healthy subjects, night-time BP decreases by 10% to 20% of daytime BP (normal dipper pattern). This circadian rhythm of BP is determined partly by the intrinsic rhythm of central and peripheral clock genes, which regulate the neurohumoral factor and cardiovascular systems, and partly by the sleep–wake behavioral pattern. Hypertensive patients without organ damage also exhibit the dipper pattern; however, those with organ damage tend to exhibit nondipper patterns with diminished night-time BP fall. Night-time BP …