Haemorheological effects of losartan and enalapril in patients with renal parenchymal disease and hypertension.
The objective of this study was to compare the effects of the angiotensin II (ang II) antagonist, losartan and the angiotensin-converting enzyme inhibitor (ACEI), enalapril on haemorheology. Twenty-nine patients with renal parenchymal disease and hypertension were enrolled in the prospective, open, parallel study that involved a 14-day washout period followed by a 120-day treatment period. Patients were allocated randomly to receive either losartan 50-100 mg/day (n = 15) or enalapril 2.5-10 mg/day (n = 14) to achieve blood pressure control <140/90 mm Hg. Blood pressure, haemorheology profile and plasma fibrinogen concentration were measured after the washout phase and after 2, 10, 60, and 120 days of treatment. The data were analysed using ANOVA with repeated measures. Twenty-seven patients completed the study. Treatment with both losartan and enalapril was associated with a significant decrease (P < 0.05) in relative high shear rate whole blood viscosity, indicating an increase in blood cell deformability. In patients taking losartan, the increase in blood cell deformability did not result in a decrease in mean whole blood viscosity due to a concomitant, significant increase in mean plasma viscosity (P < 0. 01). In contrast, the improved cell deformability in patients treated with enalapril resulted in a small and statistically insignificant decrease in mean whole blood viscosity (P = 0.06; mean change = -0.15 mPa sec). The mechanism of the increase in blood cell deformability and the rise in plasma viscosity associated with losartan remain unclear. It is possible but unproven that the improvement in intrinsic blood cell rheology with losartan and enalapril may be the result of changes in cation transport systems and/or the consequence of the protective antioxidant properties of drug metabolites.
Shand
B I
BI
Department of Nephrology, Christchurch Hospital, Christchurch, New Zealand.
D000328:Adult; D000368:Aged; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use*; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D001775:Blood Circulation / Q000187:drug effects*; D001809:Blood Viscosity / Q000187:drug effects; D004656:Enalapril / Q000627:therapeutic use*; D004907:Erythrocyte Deformability / Q000187:drug effects; D005260:Female; D005340:Fibrinogen / Q000032:analysis; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000150:complications* / Q000188:drug therapy*; D007674:Kidney Diseases / Q000150:complications*; D019808:Losartan / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies
D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D004656:Enalapril; D005340:Fibrinogen; D019808:Losartan