Awake Systolic Blood Pressure Variability Correlates With Target-Organ Damage in Hypertensive Subjects

TLDR

Blood pressure variability is increasingly linked to cardiovascular events in hypertension. The study examined whether awake blood‑pressure variability predicts target‑organ damage in patients with suspected hypertension. Systolic and diastolic BP variability were quantified as the standard deviation of mean 24‑hour recordings in 180 untreated patients, with daytime readings every 15 min and nighttime every 30 min, and target‑organ damage was measured by left‑ventricular mass index, carotid intima‑media thickness, and microalbuminuria. Higher awake systolic BP variability was associated with greater carotid intima‑media thickness and left‑ventricular mass index, independently predicting these measures and microalbuminuria, indicating that variability correlates with subclinical target‑organ damage early in hypertension.

Abstract

Growing evidence associates blood pressure (BP) variability with cardiovascular events in hypertensive patients. Here we tested the existence of a relationship between awake BP variability and target-organ damage in subjects referred for suspected hypertension. Systolic and diastolic BP variability were assessed as the standard deviation of the mean out of 24-hour, awake and asleep BP recordings in 180 untreated subjects, referred for suspected hypertension. Measurements were done at 15-minute intervals during daytime and 30-minute intervals during nighttime. Left ventricular mass index (by echo), intima-media thickness (by carotid ultrasonography), and microalbuminuria were assessed as indices of cardiac, vascular and renal damage, respectively. Intima-media thickness and left ventricular mass index progressively increased across tertiles of awake systolic BP variability ( P for trend=0.001 and 0.003, respectively). Conversely, microalbuminuria was similar in the 3 tertiles ( P =NS). Multivariable analysis identified age ( P =0.0001), awake systolic BP ( P =0.001), awake systolic BP variability ( P =0.015) and diastolic BP load ( P =0.01) as independent predictors of intima-media thickness; age ( P =0.0001), male sex ( P =0.012), awake systolic ( P =0.0001) and diastolic BP ( P =0.035), and awake systolic BP variability ( P =0.028) as independent predictors of left ventricular mass index; awake systolic BP variability ( P =0.01) and diastolic BP load ( P =0.01) as independent predictors of microalbuminuria. Therefore, awake systolic BP variability by non-invasive ambulatory BP monitoring correlates with sub-clinical target-organ damage, independent of mean BP levels. Such relationship, found in subjects referred for recently suspected hypertension, likely appears early in the natural history of hypertension.