Assessment of Patients With suspeCted Coronary Artery Disease by Coronary calciUm fiRst strATegy vErsus Usual Care Approach.

Overview

The cost of medical care in the United States far exceeds that of all other advanced economies and continues to accelerate at a rate unacceptable to our society, due primarily to the high costs of new imaging technologies and novel drugs (1). Cardiac positron emission tomography (PET) imaging is a powerful new modality for the non-invasive detection of provocable coronary ischemia in patients with low to intermediate-risk chest pain or its equivalent. Intermountain Medical Center (IMC) is performing approximately 6000 clinical cardiac PET scans annually. However, cardiac PET scans are expensive (i.e., billed at \>$5,000/scan, average receivable revenue $1500-$2000/scan). Coronary artery calcium (CAC) is a sensitive marker of coronary atherosclerosis. A CAC scan (CACS), performed by multislice computed tomography (CT), is a relatively inexpensive (\~$70-$150/scan), low-radiation dose test that marks the presence of coronary atherosclerotic plaque. The absence of CAC has been shown to be associated with very low coronary risk. ACCURATE will test whether a CAC-first strategy (i.e., risk stratification, when CAC ≤ 1, to medical management or to cardiac PET stress testing), performed routinely in symptomatic patients presenting for evaluation of possible coronary artery disease (CAD) prior to the cardiac PET stress test, can be used as a gatekeeper for progression to the expensive rubidium-PET stress (regadenoson) perfusion scan and be a major cost-saver without adversely affecting patient care or outcomes. Routinely, qualifying patients undergo CACS when they present for evaluation of possible but unknown CAD status and are referred for cardiac PET stress testing. In ACCURATE, those with CACS≤1 will then be consented and randomized to either a cardiac PET stress test strategy or a non-PET-driven medical care strategy. Subjects randomized to the cardiac PET stress test strategy will receive appropriate subsequent care depending on the outcome of the cardiac PET scan (i.e., depending on whether ischemia is present or not). Subjects randomized to the CAC-only arm will receive appropriate non-PET driven medical clinical management and follow-up. All participating subjects' electronic medical records will be reviewed indefinitely for clinical outcomes. Initial outcomes will be reported at 1-year, 2-years, and 5-years, with future analyses to be determined by the study investigators. The objective of this study is to test the hypothesis that PET stress test strategy will results in a decreasing in major adverse cardiac endpoint without exceeding $100,000 per quality-adjusted life year compared to a CAC-first strategy for screening suspected/possible coronary artery disease.