Hemorheological profiles of subjects with prehypertension

High blood viscosity is associated with increased peripheral resistance and high blood pressure (BP). Prehypertension refers to a systemic BP of 120-139 mm Hg systolic (SBP) and/or 80-89 mm Hg diastolic (DBP). Subjects with prehypertension have an increased risk of overt hypertension and incident cardiovascular disease compared with subjects who have optimal BP. In the present study, we investigated the hemorheological profiles of subjects with prehypertension. A total of 418 apparently healthy subjects were enrolled. BP, plasma lipids and glucose were measured using routine methods. Blood and plasma viscosity were measured using a cone-plate viscometer. The participants were grouped according to BP into the following categories: 'normotensive' (n=100), 'prehypertensive' (n=172), and 'hypertensive' (n=146). The blood viscosity, plasma viscosity and hematocrit of the prehypertensive subjects were higher than those of the normotensive subjects (P<0.01), but they were comparable to those of the hypertensive subjects. In simple correlation analyses, SBP and DBP were directly and significantly correlated with age, body mass index (BMI), blood glucose, hematocrit, plasma viscosity and blood viscosity. In multiple regression analyses, age, fasting blood glucose and plasma viscosity were independently related with SBP, whereas blood viscosity, fasting blood glucose and BMI significantly predicted DBP. These data demonstrate that BP in the range of so-called prehypertension is accompanied by important hemorheological changes, which are similar to those observed in people with overt hypertension. These results could explain the increased cardiovascular risk observed in these subjects as well as their susceptibility to hypertension.