Epidemiology and Pathophysiologic insights of coronary atherosclerosis relevant for contemporary non-invasive imaging

In the past few years significant changes have taken place in the diagnostic and therapeutic approach to patients with coronary artery disease (CAD) and/or ischemic heart disease (IHD). New discoveries about the development and progression of coronary atherosclerosis have changed the clinical landscape. At the same time a marked decrease in cardiovascular (CV) mortality and CAD incidence have been observed in many Countries but particularly in the most industrialized ones. This fall has been also observed in the incidence of stroke, sudden death, myocardial ischemia, myocardial infarction (MI), and prevalence of CAD. As a consequence, an increasing number of patients with chest pain exhibits non-significant stenosis at both invasive and non-invasive coronary angiography and the rate of coronary vessels revascularizations has greatly reduced. Coronary atherosclerosis and its characteristics have shown to be both diagnostic and therapeutic targets beyond obstructive CAD. The decreased prevalence of CAD in the general population has modified the pre-test probability (PTP) of disease. In this landscape the conventional stress imaging tests appear to have limited accuracy making the diagnosis of obstructive CAD very challenging. These diagnostic tests have been introduced and tested in a population with a much higher probability of disease and therefore the contemporary accuracy of these old tests appear much lower than in the past. In addition, in the past few years the relevance of the traditional ischemia guided coronary intervention strategy has been questioned. Given the low CV events granted by an optimal medical therapy in CAD the major attention has been directed on detecting coronary atherosclerosis. The earlier the better. At the same time, a growing number of data from clinical studies have shown a significant prognostic role for non-obstructive CAD and coronary atherosclerosis. All these facts have shifted the clinicians' attention from the functional evaluation of the coronary circulation to the anatomic burden of disease.