The effect of long-term treatment with hypotensive drugs on blood viscosity and erythrocyte deformability in patients with essential arterial hypertension.

This study examined ninety-six patients with essential arterial hypertension (WHO grade I-II) who had been under treatment for a period of at least one year before participating in the study. When the study began the patients received no drug treatment for one month. At the end of this washout period their basal situation was evaluated and drug treatment was begun (26 patients on calcium antagonists, 39 on beta-blockers and 31 on angiotensin converting enzyme inhibitors). The patients were evaluated again after one and two years of uninterrupted treatment with the chosen medication. The results obtained indicate that in a basal situation hypertensive patients have higher blood viscosity and erythrocyte rigidity values than the control group. Regardless of the drug treatment used, the patients experienced during the study a progressive deterioration of their hemorheological situation consisting of an increase in red blood cell rigidity and increased blood viscosity. These results indicate the importance of evaluating the hemorheological parameters of hypertensive patients and suggest that it may be advisable to include in their treatment some kind of medication that prevents progressive rheological deterioration.