Cardiac Syndrome X Prognosis

While historically Cardiac Syndrome X (CSX), characterized by the triad of chest pain, abnormal stress testing and no obstructive coronary artery disease (CAD), has been believed to have a benign prognosis, newer data documents otherwise. Multiple findings in larger, better characterized populations with longer follow-up time periods document a relatively high risk for major adverse cardiac events in those subjects with mechanisms related to microvascular coronary dysfunction (MCD) and manifestations of ischemia. Specifically, CSX related to MCD has an adverse prognosis and health care cost expenditure comparable to obstructive CAD in both stable angina and unstable acute coronary syndrome patient populations. Invasive assessment of coronary reactivity testing, including endothelial and non-endothelial pathway testing provides potent prognostic information in subject with normal and minimal diseased coronary arteries. Additional assessment by non-invasively determined coronary or myocardial blood flow reserve provides additive prognostic value to routine coronary angiography. The presence of persistent chest pain alone at 1 year following index coronary angiography predicts an adverse prognosis. MCD predicts a relatively greater proportion of heart failure events compared to myocardial infarction, suggesting potential links between MCD and heart failure with preserved systolic function, although longer term follow-up of ventricular function has not been performed. The high prevalence of this condition, adverse prognosis and substantial health care costs particularly in women, coupled with the lack of evidence-base regarding treatment places intervention trials in this patient population as a research priority area.