Effects of low-dose aspirin on endothelial function in hypertensive patients

Background: It has been reported that administration of low-dose aspirin si gnificantly reduces the frequency of major cardiovascular events in patient s with hypertension and coronary artery disease. It is generally considered that the preventative effects of long-term aspirin administration on major cardiovascular events are due to the inhibition of platelet aggregation. Hypothesis: It is not known whether administration of low-dose aspirin rest ores endothelium-dependent vasodilatation, and this study was undertaken to prove or disprove this question in patients with hypertension. Methods: How-mediated endothelium-dependent dilatation and glyceryl trinitr ate-induced endothelium-independent dilatation were investigated in 18 hype rtensive patients and 10 normotensive control subjects. In the hypertensive patients, flow-mediated dilatation was investigated and cyclic guanosine m onophosphate plasma (cGMP) was measured before and at 8 weeks after the adm inistration of 162 mg of aspirin. Results: Flow-mediated dilatation before aspirin administration was more re duced in the hypertensive patients than in the control subjects (6.4 +/- 2. 0% vs. 11.3 +/- 2.3%, p < 0.0001). Glyceryl trinitrate-induced dilatation b efore aspirin administration was similar in hypertensive patients and contr ol subjects. Flow-mediated dilatation after aspirin administration was impr oved compared with that before aspirin administration (10.4 +/- 3.5% vs. 6. 4 +/- 2.0%, p < 0.0004). The cGMP product after aspirin administration was significantly higher than that before aspirin administration. Conclusions: Administration of low-dose aspirin may restore the endothelium -dependent vasodilatation in hypertensive patients. Furthermore, increased nitric oxide production may play a partial role in the improvement in endot helial function induced by administration of low-dose aspirin.