J Clin Hypertens (Greenwich). 2012;14:871–876. ©2012 Wiley Periodicals, Inc.
Isolated systolic hypertension (ISH) is a common condition in the elderly that is associated with endothelial dysfunction. Concerning the effect of type of hypertension on coronary microvascular function, coronary flow reserve (CFR) in patients with ISH was evaluated and the results were compared with patients with combined systolic/diastolic hypertension (SDH). Seventy-six elderly patients (older than 60 years) who were free of coronary artery disease and diabetes mellitus were enrolled in the study (38 with ISH and 38 with combined SDH). Using transthoracic Doppler echocardiography, CFR was calculated as the ratio of hyperemic to baseline diastolic peak flow velocities. A CFR value of >2 was accepted as normal. The mean age was 68.6±6.3 years and the groups had similar features with regard to demographic and clinical characteristics. Patients with ISH had significantly lower CFR values compared with those with combined SDH (2.22±0.51 vs 2.49±0.56, respectively; P=.03). On multivariate regression analysis, ISH (β=−0.40, P=.004) and dyslipidemia (β=−0.29, P=.04) were the independent predictors of CFR. These findings indicate that CFR, an indicator of coronary microvascular/endothelial function, is impaired more profoundly in patients with ISH than in patients with combined SDH.