From Clinical Considerations to Theory - Blood Pressure Variability Profiles and Patterns.

BACKGROUND Blood pressure variability (BPV) has recently been associated with adverse cardiovascular (CV) events, endothelial dysfunction as well as both CV and non-CV morbidity and mortality. Different BPV indicators have been associated with increased CV risk. METHODS We included 744 hypertensive patients referred to our clinic for uncontrolled arterial hypertension (HTN) between 2012 and 2014, with a minimum of 40 successful daytime and 8 successful nighttime readings on automatic blood pressure monitoring (ABPM Meditech-05 device, recordings at 15-20 minutes intervals during daytime and 20-30 minutes intervals during nighttime). Exclusion criteria were presence of secondary HTN, significant CV disease and estimated glomerular filtration rate <30 ml/min/1.73 m2. BPV was expressed as dipping pattern, BP load, SD of 24-hour mean BP, average weighted SD and average real variability (ARV). RESULTS All patients were known hypertensives, however their average blood pressure (BP) values on 24-hour ABPM were below 135/85 mmHg. The average dipping was higher in dippers (p<0.01) and nighttime systolic BP (SBP) load was increased among the non-dippers group (p<0.01). Mean diastolic BP (DBP) was slightly increased in dippers vs. non-dippers (75.82 ± 10.28 mmHg vs. 71.42 ± 10.17 mmHg, p<0.01). Of the total of 407 dippers, 31.2% displayed an extreme dipping pattern, whereas 29.67% of the 337 non-dippers were risers. In our study, average SBP, daytime and nighttime SBP SD and ARV did not differ significantly between the two extreme groups, as opposed to classical indicators such as SBP load (p<0.01) and weighted SD (p 0.02). CONCLUSION In the emergency hospital setting, hypertensive patients can have normal mean BP values, but still can display a very high variability and in most cases abnormal dipping profiles, requiring a strictly controlled drug therapy that is able to match each individual's chronobiology.