Relationships between 24 h blood pressure load and target organ damage in patients with mild-to-moderate essential hypertension

Objective To analyse the relationships between 24 h blood pressure load (th e percentage of systolic/diastolic blood pressures exceeding 140/90 mmHg wh ile awake and 120/80 mmHg during sleep) and some indices of hypertensive ta rget organ involvement, independently of the mean level of 24 h blood press ure. Methods One hundred and thirty patients with mild-to-moderate hypertension underwent 24 h ambulatory blood pressure monitoring, ocular fundus examinat ion, microalbuminuria assay and two-dimensional guided M-mode echocardiogra phy. The study population was divided into subsets according to the systoli c and diastolic 24 h blood pressure load values predicted from the regressi on equation relating 24 h blood pressure load to 24 h mean blood pressure. The subjects with an observed load above this predicted value were included in the higher blood pressure load groups, the remaining ones being include d in the lower groups. Results Relative myocardial wall thickness and total peripheral resistance were greater, and mid-wall fractional shortening, end-systolic stress-corre cted mid-wall fractional shortening and cardiac index lower, in the subject s with a higher systolic blood pressure load. Moreover, the stroke index:pu lse pressure ratio was reduced, and a greater prevalence of hypertensive re tinopathy was observed in the higher systolic load group. On the contrary, no statistically significant difference was found for any of the cardiac, r enal and funduscopic parameters examined when the two groups with a higher and lower 24 h diastolic blood pressure load were compared. Conclusions Our results seem to suggest that, in mild-to-moderate arterial hypertension, a high 24 h systolic blood pressure load may be associated, i ndependently of the average level of 24 h systolic ambulatory blood pressur e, with an adverse cardiovascular risk profile. (C) 2001 Lippincott William s & Wilkins.