Thromboviscometry as a tool for evaluation of thrombotic risk in systemic hypertension

In the present study, thromboviscometry was used to analyse the dynamic coa gulation of blood in patients with severe systemic hypertension. Fibrinogen levels and whole blood viscosity, corrected for 45% haematocrit, were also monitored. The efficacy of thromboviscometry as an adjunct diagnostic tool , for determination of thrombogenic potential, was compared with that of de tection of fibrinogen levels in the blood. Twenty-five cases of severe syst emic hypertension (HT) in the 40 to 50-year age group were compared with 50 age and sex-matched normal controls (NC). The changes in whole blood visco sity were monitored with time at a constant shear rate, in a concentric cyl inder viscometer, during the clotting process. The total thrombus formation time was significantly less in the HT group when compared with NC (238.9 /- 38.72 s vs 315.1 +/- 32.93 s, P < 0.0005), The time required for a sudde n increase in viscosity during clotting was also significantly lower in the HT group (205.9 +/- 34.37 s vs 272.9 +/- 28.83 s, P < 0.0005) and the over all rate of increase of thrombus viscosity was significantly higher in HT ( 245.2 +/- 36.44 centiPoise/s vs 183.6 +/- 16.32 centiPoise/s, P < 0.0005). There was, however, no significant change in the fibrinogen levels of the t wo groups. Thus, thromboviscometry was a more sensitive indicator of the th rombogenic potential of blood in HT than fibrinogen levels, The increased t hrombogenic potential of hypertensive blood could be due to acceleration of the initial part of the coagulation process during the activation of facto r Xa and the formation of thrombin.