Cardiac syndrome X and endothelial dysfunction: new concepts in prognosis and treatment.

Cardiac syndrome X (CSX), or angina with no flow-limiting stenosis on coronary angiogram, has been regarded as a condition with an excellent prognosis despite variable symptomatic improvement. Newer data show that patients with CSX with endothelial dysfunction have an increased risk for future adverse cardiac events. Current hypotheses of CSX pathophysiology emphasize a dysfunctional vascular endothelium that leads to microvascular ischemia. Treatments that target improving endothelial function, such as statins, angiotensin-converting enzyme inhibitors, estrogen, and lifestyle modification, are promising additions to treatment regimens for CSX. The goal of this article is to provide information for improved diagnosis, risk stratification, and therapy for the population with CSX.