Angina pectoris in patients without flow-limiting coronary artery disease (cardiac syndrome X). A forest of a variety of trees

Abstract

Coronary heart disease (CHD) represents an important problem worldwide. At present, more women than men are evaluated for CHD and it has been recognized that the prevalence of this pathology in women is at least the same as in men. We have learned that cardiac syndrome X (CSX) is frequent because worldwide each year millions of people (mostly women) with angina pectoris without flow-limiting epicardial pathology are identified. Data from large myocardial infarction registries suggest a 5% to 25% prevalence of cases without flow-limiting coronary pathology. It must, however, be considered that these people are said to have normal coronary arteries by visual analysis of biplane coronarography. On the other hand, as demonstrated from autopsy, and in vivo by ultrasound intravascular studies, it would be more appropriate to say that in the majority of these cases no obstructive or flow-limiting coronary pathology was detected by coronarography. In CSX, endothelial dysfunction and microvascular dysfunction, sometimes with coronary microvascular spams and epicardial coronary artery spasm, have been recognized as pathophysiologic mechanisms. In CSX, symptoms and pathologic signs are the same in patients with flow-limiting coronary pathology. The difference lies in the fact that the mechanisms of myocardial ischemia are microvascular and flow-limiting epicardial coronary pathology is absent. By interplay, the pathologic entities at work in CSX are linked with poor long-term outcome. The prevalence of these outcomes is probably smaller than in patients with flow-limiting coronary pathology but we lack precise values. Nonetheless, severe cardiovascular complications are frequent in CSX and it is thus the pathology is not benign. Drugs used in coronary ischemic disease are empirically prescribed to treat CSX, but we lack data from specific trials. It seems that statins and ranolazine might exert positive effects. However, specific research to target interventions in CSX would be necessary.