Background: Myocardial perfusion imaging (MPI) is the predominant diagnostic tool for evaluating outpatients with typical and atypical symptoms suggestive of obstructive coronary artery disease (CAD) and is commonly followed by invasive coronary angiography in patients with abnormal findings. Despite this paradigm, a significant proportion of patients do not need intervention, suggesting better diagnostic methods are needed to identify appropriate patients who would benefit from the risks, resource utilization, and healthcare costs incurred after a positive MPI. A previously validated, blood-based test incorporating age, sex and genomic expression score (ASGES) utilizing peripheral blood cell expression has demonstrated clinical validity in assessing the likelihood of obstructive CAD (≥50% luminal diameter stenosis by quantitative coronary angiography) early in the cardiac workup.
Objective: The objective of this study is to evaluate if the utilization of the ASGES in conjunction with a positive MPI would assist in the determination of a patient’s risk of obstructive coronary artery disease.
Methods: A total of 249 patients (mean age 58, 45% female) from 59 sites in the PREDICT (NCT00500617) and COMPASS (NCT01117506) studies were identified with a positive MPI study, defined as at least one reversible of fixed defect consistent with obstructive CAD and a subsequent invasive coronary angiography. ASGES scores were performed in all patients and were categorized into 3 groups based on score: low (1-15, 25%), mid-range (16-27, 43%) and high (28-40, 32%). Obstructive CAD rates defined by invasive coronary angiography were measured. The association between obstructive CAD and ASGES was evaluated using Cochran-Armitage trend test and area under the receiver-operating characteristics curve (AUC) analyses.
Results: The rate of obstructive CAD among patients with a positive MPI was 35% (88/249). There was a net redistribution of risk based on ASGES testing in 52% (49/88) of these patients. The rate of obstructive CAD was 11% (7/63), 37% (39/106), and 53% (42/80) in the low, mid-range, and high score groups respectively (p<0.001). AUC for the ASGES use with a positive MPI was 0.704.
Conclusion: The ASGES test, when used in patients after positive MPI, improved the diagnostic accuracy in the assessment of obstructive CAD. The use of this precision medicine test may help minimize unnecessary referral of low-intermediate risk patients as well as improve diagnostic yield among patients with abnormal MPI findings scheduled to undergo invasive coronary angiography.