[Effects of raloxifene on endothelial function and hemostasis in women with ischemic heart disease]

Modulation of vascular tone is one of the most relevant estrogen effects. A beneficial effect on endothelial function in postmenopausal women has also been proposed for the selective estrogen receptor modulator raloxifene. However, its effects in women with established cardiovascular disease have not been fully elucidated. In addition, recent trials have generated controversy regarding thromboembolic risk with raloxifene use. The aim of the study was to assess the effect of raloxifene on: a) endothelial function and b) coagulation and fibrinolysis pathways.

The MERCED trial was a prospective, randomized clinical trial. Thirty-three postmenopausal women with ischemic heart disease were enrolled in the study. Raloxifene treatment was administered for a 3-month period, according to a double-blind crossover design. Assessment of vascular function and biologic parameters related to coagulation pathways were conducted at various pre-established time-points.

Flow-mediated dilatation was severely impaired in the study population, and raloxifene had no effect on endothelial function. Treatment with raloxifene was associated to decreased levels of fibrinogen (3.41 [3.11-3.74] vs. 3.69 [3.40-4.00], P<.05); prothrombin fragments F(1+2) (0.93 [0.77-1.12] vs. 0.94 [0.78-1.15], P<.05); and plasmin/antiplasmin complexes (211 [166-267] vs. 242 [199-295], P<.01).

The present study provides evidence that in postmenopausal women with demonstrated endothelial dysfunction and ischemic heart disease, mid-term treatment with raloxifene does not affect endothelial function. In the MERCED trial, no increased thrombotic risk was observed, but a decreased thrombotic and fibrinolytic activity was observed with raloxifene. Further studies are required to determine whether thrombotic risk is associated with specific clinical characteristics or subgroups of postmenopausal women with cardiovascular disease. Full English text available from: www.revespcardiol.org.