The role of whole blood viscosity in premature coronary artery disease in women

Background: Impaired hemorheology has been demonstrated in atherosclerotic disease and has shown a relationship with classical risk factors. Blood viscosity (η), being the ratio of shear stress over shear rate, is an important parameter of hemorheology. In women with premature coronary artery disease (CAD), the underlying risk factors are a matter of debate and the role of whole blood viscosity in its pathogenesis has not been documented. Aim: To investigate the association of whole blood viscosity with premature CAD in women, with complaints suggestive of angina pectoris. Methods: Eighty-eight women (mean age 53 years) were divided into two groups, those with a high likelihood of CAD (LIKELI+) and those with a low likelihood of CAD (LIKELI−), based on medical history and technical investigations. Assessment of risk factors comprised smoking, diabetes mellitus, arterial hypertension, left ventricular hypertrophy (LVH), systolic and diastolic blood pressures, total low-density lipoprotein (LDL)- and high-density lipoprotein (HDL)-cholesterol, triglycerides, body mass index, menopause, hormone replacement therapy, uric acid and creatinine, and predicted 10-year cardiovascular risk according to the Framingham study was calculated. Whole blood viscosity was determined at 37 °C using a rotational cone-and-plate viscosimeter. Results: Baseline characteristics did not differ significantly between the groups except for antiplatelet therapy (P=0.001), prevalence of diabetes mellitus (P=0.002), predicted 10-year cardiovascular risk (P=0.007), essential hypertension (P=0.02), LVH (P=0.03) and smoking habits (P=0.04). LIKELI+ women had a significantly higher whole blood viscosity at all shear rates compared with LIKELI− women (P<0.05). All blood viscosities measured from 25 to 125 s−1 were highly significantly (P<0.0001) correlated with η250 s−1. Univariate correlates with η250 s−1 comprised triglycerides (P=0.006) and haematocrit (P=0.026). Binary logistic multivariate regression analysis for high likelihood of CAD revealed that only presence of arterial hypertension (P<0.0001) was predictive. Multiple regression analysis demonstrated that haematocrit (P=0.001) and likelihood of CAD (P=0.01) were the only significant determinants of η250 s−1. Conclusion: In this study, blood viscosity did not appear as an independent risk factor for the prediction of premature CAD in women. Viscosity may act as a marker of CAD or of classical risk factors.