Reasons for discordance between positron emission tomography (PET) myocardial perfusion imaging (MPI) results and subsequent management

Background: Referral patterns to coronary angiography following positron emission tomography (PET) myocardial perfusion imaging (MPI) and reasons for non-referral following abnormal PET MPI are largely unknown. Methods: Referral rates to coronary angiography within 90 days post PET MPI were determined. A random subset of 100 patients with severe (≥ 10%) ischemia on MPI between 2014-16 who were not referred for angiography were examined to better understand reasons as to why patients with high-risk MPI findings did not undergo coronary angiography. Results: Among 19,282 unique patients, overall rate of 90-day coronary angiography was 18.5% (3574/19282). Among patients with severe ischemia, 64.1% (1930/3011) underwent angiography within 90 days; the rate was lower in those with mild-moderate (20.6% [1010/4898]) and no ischemia (5.6% [634/11373]). In the random sample of 100 patients, the most common physician reasons for non-referral were uncertainty regarding whether the test results were responsible for the patient’s presenting symptoms, renal failure, and patient age, frailty, or cognitive status, while patient preference for medical management was by far the most common patient reason. Conclusion: Referral rates for coronary angiography after PET correlate with severity of ischemia. However, there appear to be opportunities to reconsider testing for instances when results will not change clinical management.