Blood pressure (BP) homeostasis depends on complex physiological mechanisms that involve continuous interactions of the cardiovascular, renal, neural, and endocrine systems. These mechanisms must also guarantee the maintenance of adequate cardiac output, even in situations of rapid circulatory variations. One of these situations is related to the dynamic posture changes, from lying to standing, when the rapid reduction in venous return can affect preload, stroke volume, and mean BP. Orthostatic hypotension (OH) is a manifestation of autonomic dysfunction and occurs when cardiovascular adaptive mechanisms fail to compensate for those changes when assuming the standing position.

Diagnosing OH requires the demonstration of significant persistent BP decrease during orthostasis, either by the bedside active-standing test or a tilting test. National and international guidelines have endorsed the definition of OH as a ≥20 mmHg drop in systolic blood pressure (SBP) or a ≥10 mmHg drop in diastolic blood pressure (DBP) within 3 minutes after standing, regardless of the presence of symptoms. ^– This definition was first established by a consensus in 1996 and was based on several small physiology studies as well as on pragmatic considerations. Upon this definition, growing evidence has been shown that OH predicts all-cause mortality ^, and incidence of cardiovascular disease, ^, being even more relevant than the ambulatory BP monitoring-derived nighttime reverse dipping for predicting cardiovascular events . A recent meta-analysis involving 121,913 individuals and a median follow-up of 6 years reported that OH was associated with a 50, 41, and 64% greater risks of all-cause death, coronary heart disease, and stroke, respectively.

[…]