PROGNOSTIC VALUE OF 24-HOUR BLOOD-PRESSURE VARIABILITY

Objectives: Evaluation of the prognostic value of 24-h blood pressure averages and 24-h blood pressure variability. Design: After an initial thorough clinical and laboratory evaluation which included 24-h conti nuous ambulatory blood pressure monitoring, a group of hypertensive pa tients were re-examined after an average of 7.4 years. End-organ damag e at the follow-up visit was related to different measures of blood pr essure levels and variability obtained at the initial or the follow-up visit or both. Methods: Seventy-three patients with essential hyperte nsion of variable severity, in whom ambulatory blood pressure was moni tored intra-arterially for 24 h (Oxford technique) were re-examined at a follow-up visit (including echocardiographic assessment of left ven tricular mass index) 4-13 years later (mean 7.4 years). The severity o f end-organ damage was quantified by a score and related to clinic blo od pressure at follow-up and to (1) clinic blood pressure, (2) 24-h bl ood pressure mean, (3) 24-h short-term and long-term blood pressure va riability, and (4) end-organ damage, all assessed at the initial visit (multiple regression analysis). Results: The set of independent varia bles considered was significantly related to end-organ damage at follo w-up (R = 0.51). The individual variables most important in determinin g end-organ damage at follow-up were clinic blood pressure at the foll ow-up visit (P < 0.01), the initial level of end-organ damage (P < 0.0 5) and long-term blood pressure variability (among half-hour standard deviation of 24-h mean blood pressure) at the initial evaluation (P < 0.05). The prognostic individual weight of the other haemodynamic para meters considered was less and not statistically significant. Conclusi ons: The results confirm that the level of blood pressure achieved by treatment and the degree of end-organ damage at the time of initial ev aluation are important determinants of future end-organ damage related to hypertension. They also constitute the first longitudinal evidence that the cardiovascular complications of hypertension may depend on t he degree of 24-h blood pressure variability.