Is dyspnea the new angina? The ever-changing profile of patients referred for CAD evaluation

The prevalence, severity, and manifestation of coronary artery disease (CAD) have been changing. In the past several decades, there has been a decline in the incidence of cardiac death and myocardial infarction.^1,2 Simultaneously, the presentation of stable CAD has evolved as well. It is increasingly clear that the Diamond and Forrester estimates of pretests likelihood of CAD from the 1970s markedly overestimate the probability of CAD in present-day patient populations,^3,4 and the more contemporary European Society of Cardiology pretest probability predicts obstructive CAD, cardiovascular events, and myocardial perfusion abnormalities more accurately.^5,6 Furthermore, the prevalence and severity of myocardial perfusion abnormalities on SPECT myocardial perfusion imaging (MPI) studies have progressively decreased over the past 3 decades.^7,8 These observations may be attributable to decrease in tobacco use, increase in statin use, and more aggressive management of hypertension. Furthermore, the clinical suspicion threshold to test patients for CAD may have been dialed down over the years to include patients with lower likelihood of CAD, further diluting the prevalence and severity of CAD in contemporary patient populations.^9,10 Concomitant to these trends, the patient population has been aging along with an increased prevalence of diabetes mellitus and obesity, decreased exercise capacity, and increased utilization of pharmacologic stress modality among patients undergoing stress MPI.¹⁰ …