Recent literature suggests that the frequency of abnormal SPECT myocardial perfusion imaging (MPI) has decreased over the past two decades despite an increase in the prevalence of many cardiac risk factors. This study examined the trends in the prevalence of obstructive coronary artery disease (CAD) by abnormal and ischemic MPI and invasive angiography.

We analyzed all patients who underwent stress MPI or invasive angiography at two academic centers between January 1996 and December 2012, for their demographic data and study results.

A total of 108,654 MPI studies were performed. Over time, the percentage of patients with hypertension, hyperlipidemia, diabetes, and a history of smoking increased. There was a decline in the prevalence of abnormal MPI studies in all patients as well as in those with and without known CAD (from 47.2%, 71.8%, and 31.4% in 1996 to 33.9%, 64.8%, and 18.8% in 2012, respectively, all P < .0001). Similarly, there was a decline in the prevalence of ischemic MPI studies in all patients as well as in those with and without known CAD. A total of 142,924 invasive angiograms were performed. There was a decline in the prevalence of one-vessel and multi-vessel coronary disease (from 29.1% and 53.6% in 1996 to 22.4% and 35.9% in 2012, respectively, all P < .0001).

There has been a temporal decline in the prevalence of abnormal and ischemic MPI studies as well as the frequency and extent of obstructive CAD on angiography. However, this decline was not to the same extent as previously reported, and the overall 34% abnormal MPI rate, with 19% in patients with no known CAD and 65% in patients with known CAD, remains a clinically relevant percentage of patients tested.