Significance of Estrogen in Acute Coronary Syndrome

Estrogen, a cardioprotective agent, potentiates acetylcholine-induced increase in coronary blood flow, decreases coronary endothelin-1 levels, reduces ischemia, enhances fibrinolysis, shifts markers of coagulation toward hypercoagulability, and increases blood levels of matrix metalloproteinase-9, involved in plaque disruption and inflammatory markers like interleukin-6 and C-reactive protein. Rates of cardiovascular disease in women tend to rise during menopause, when estrogen level decreases. Hormone replacement therapy (HRT) provides exogenous estrogen to encounter the deficiency of estrogen into body, which demonstrates favorable cardioprotective effects, if initiated few years within the onset of menopause. However, use of HRT is controversial in preventing progression of the diseases at the later stages; since it cannot repair the damage already occurred. The therapy reduces the progression rate of atherosclerosis in post-menopausal women, who are not suffering from cardiovascular disease. However, in patients with cardiovascular disease or risk factors, estrogen therapy enhances cardiac events.