Short-term blood pressure variability in relation to outcome in the International Database of Ambulatory blood pressure in relation to Cardiovascular Outcome (IDACO)

Ambulatory blood pressure monitoring not only provides information on the blood pressure level, but on the diurnal changes in blood pressure as well. The present review summarizes the main findings of the International Database on Ambulatory blood pressure in relation to Cardiovascular Outcome (IDACO) with regard to risk stratification based on short-term blood pressure variability. An exaggerated morning surge, exceeding the 90 ^th percentile of the population, is an independent risk factor for mortality and cardiovascular and cardiac events. Conversely, a sleep-through or pre-awakening morning surge less than 20 mm Hg in systolic blood pressure is probably not associated with an increased risk of death or cardiovascular events. Blood pressure variability represented by the average of the daytime and nighttime SD weighted for the duration of the daytime and nighttime interval (SD _dn) and by average real variability (ARV24) predicted outcome, but only improved the prediction of the composite cardiovascular events by 0.1%. Overall, results of analyses using the IDACO support the concept that short-term blood pressure variability adds to risk stratification, but 24-hour ambulatory blood pressure level is the most valuable predictor for use in clinical practice.