Abstract Body (Do not enter title and authors here): Background: PET/CT stress test may be performed to risk stratify patients including those without known coronary artery disease (CAD) who may be at risk for short-term adverse cardiac events. In patients with low- to moderate (LTM) risk for short-term MACE and without a known history of CAD, a small percentage of these patients will undergo a coronary angiogram within 90-days, of which some will be diagnosed with high-grade stenosis. The purpose of this study is to determine factors associated with this approach and findings.
Methods: Patients without a history of known CAD (n=43,271) undergoing a PET/CT from 2018-2023 at Intermountain Health, with scan interpreted clinically as LTM short-term risk for adverse cardiac events, and ischemic burden <10% (n=38,388) were studied. To determine factors associated with a decision to proceed with a coronary angiogram and the presence of high-grade CAD (>70% stenosis in any vessel), an a priori list of clinical data and PET/CT results were examined.
Results: Within 90 days of the LTM risk PET/CT, 3,163 (8.2%) had a coronary angiogram. Of these, 806 (25.5% of angiograms and 2.1% of total LTM) had high-grade CAD. The PET/CT ancillary findings were associated with the largest odds of performing an angiogram and the presence of high-grade CAD (Tables). Factors most likely to be associated with performing an angiogram were an ischemic burden of 7.5-10% (adjusted-OR [adj. OR]=11.54), coronary artery calcification (CAC) score of >300 (adj.-OR =1.62), and myocardial blood flow (MBF) of <1.5 (adj. OR=2.25 compared to >MBF 2.3). Other clinical parameters associated, after adjustment, with an angiogram were age, male sex, hypertension, elevated troponin, and inpatient status. Many of the same factors were found to be associated with the identification of high-grade CAD. However, being an inpatient was associated with increased odds of angiogram but a decrease in odds of high-grade CAD.
Conclusions: In patients without a known history of CAD who underwent PET/CT clinically adjudicated as LTM short-term risk and ischemic burden <10% of cardiac events, subsequent coronary angiograms and high-grade CAD were not common. High-grade CAD was associated with PET/CT findings of ischemic burden of 7.5%-10%, CAC, and MBF. This indicates that attention to these findings may have a role in the decision to perform catheterization to identify high-grade CAD despite an interpretation of LTM short-term risk.