BackgroundIndividuals with systolic-diastolic hypertension (SDH, systolic blood pressure (SBP) >160 mmHg and diastolic blood pressure (DBP) >90 mmHg) are at increased risk of thrombotic complications, such as stroke and heart attacks, which may be related to a hypercoagulable state. Individuals with only isolated systolic hypertension (ISH; i.e. SBP >160 mmHg but DBP<90 mmHg) are also at significant cardiovascular risk. We hypothesized that patients with ISH would exhibit a prothrombotic state similar to that seen in SDH. A secondary hypothesis was that individuals with ISH had similar echocardiographic parameters to those seen in SDH.MethodsWe measured indices of haemorheology, endothelial dysfunction, thrombogenesis and platelet activation in 23 individuals with ISH (mean blood pressure 193/82 mmHg), who were compared with 51 matched patients with SDH (mean blood pressure 198/112 mmHg) and 34 age- and sex- matched normotensive healthy control individuals (mean blood pressure 130/78 mmHg). Echocardiographic parameters in patients with ISH were compared to those from patients with SDH.ResultsMean plasma viscosity (an index of blood rheology, ANOVA,P= 0.001), von Willebrand factor (an index of endothelial damage,P= 0.013), plasminogen activator inhibitor-1 and lipoprotein (a) (both markers of thrombogenesis; Kruskal-Wallis test, bothP< 0.001) were all significantly raised in ISH and SDH relative to controls. Individuals with SDH also had high mean plasma fibrinogen (P= 0.018) and haematocrit (P= 0.010) levels compared with control individuals. There were no significant differences in levels of fibrin D-dimer or the platelet activation marker soluble P-selectin in the hypertensive patients (i.e. ISH and SDH) compared with control individuals. Patients with ISH had similar M-mode and Doppler echocardiographic parameters compared to patients with SDH.ConclusionsWe conclude that individuals with ISH have abnormalities in plasma prothrombotic factors and markers of endothelial dysfunction, and echocardiographic parameters, broadly similar to that seen in SDH. This is consistent with the increased risk of thrombotic events (strokes and heart attacks) in patients with ISH.