Normal coronary arteries: clinical implications and further classification.

The term "chest pain with normal coronary arteries" encompasses a large number of different cardiac pathophysiological abnormalities, including impairment of coronary flow reserve, endothelial dysfunction, and early atherosclerosis that, in most cases, cannot be readily differentiated one from the other. To study early coronary atherosclerosis, physicians must look beyond contrast filled arteries (so called lumenology). Angiograms cannot evaluate the vessel wall, plaque distribution and composition or other morphology. Plaques are often angiographically not visible due to their small size and compensatory enlargement (outward remodeling) of the coronary arteries. As a result, the search for an underlying atherosclerotic process remains ongoing. Available clinical studies showed that many patients with chest pain and normal angiography have early atherosclerosis as documented by intravascular ultrasound imaging, reduced coronary flow reserve and coronary endothelial dysfunction. Additional studies showed that patients presenting with normal coronary angiography have recurrent coronary events at long-term follow up. Research to determine if improved diagnosis and treatment of quantitatively low degrees of atherosclerosis lead to improved outcomes of patients with normal angiography should be undertaken.