The Computed Tomography-derived Fractional Flow Reserve STAT Trial

New or worsening chest discomfort is the most common symptom of coronary artery disease
(CAD), which is plaque build-up in the arteries that supply the heart muscle with blood.
Chest pain is one of the most common reasons for emergency department (ED) visits, with an
estimated 8 million new cases every year. Evaluation of chest pain is expensive and time
consuming, even though 75% of the time it is not due to CAD. It is necessary to carefully
define the amount of CAD, even if initial tests reveal no heart attack, because this symptom
may progress to heart attack and death if missed.

Coronary artery computed tomography angiography of the heart (CCTA) is one of the most
sensitive tests to detect serious CAD in appropriately selected patients.In 85% of acute
chest pain (ACP) ED cases tested by CCTA, no CAD or very mild CAD is found, leading to rapid
discharge or an alternative diagnosis. However, in the 15% of patients with significant CAD
found on CCTA, further evaluation with either stress testing or heart catheterization, and/or
hospital admission is required. Since 2015, Beaumont Health hospitals have employed a new
FDA-approved test, called CT fractional flow reserve (CTFFR), that can analyze flow down the
heart arteries by computer analysis of the original CT images. Results from an analysis of
147 patients suggest that 67% of the time, CTFFR showed no significant flow limitation,
providing for the potential to defer invasive testing or treatment for a trial of medical
therapy.

The use of CTFFR on ED patients is novel, and it is not yet part of the standard of care
(SOC). Standard care of patients with definite CAD on CCTA continues to be hospital
admission, stress testing and/or heart catheterization for further diagnosis. Both CTFFR and
standard care continue to be used at Beaumont Health, and it is important to determine if one
or the other diagnostic strategy is superior. This study is designed to directly compare
standard care and CTFFR for diagnosis and management of ACP patients with definite CAD on
CCTA.

Inclusion Criteria:

- Emergency department chest pain suspicious for ACS based on history and physical
examination.

- At least one biomarker (troponin) and electrocardiogram with no evidence of definite
ACS.

- A completed CCTA demonstrating >50% but <90% stenosis of at least one coronary artery
branch.

- CCTA test images with sufficient diagnostic quality for CTFFR analysis.

- Ability and willingness to provide informed consent.

Exclusion Criteria:

- Left main coronary stenosis of 50% or greater.

- CCTA lesions demonstrating stenosis >90% ("subtotal"), or complex, high-risk plaque
characteristics resulting in an a priori recommendation for triage to CATH by the CCTA
interpreting physician.

- Attending physician a priori decision for CATH.

- Previous coronary stent, coronary bypass or prior known myocardial infarction.

- Clinical instability, such as hypotension, signs of shock, and/or accelerating chest
pain requiring admission.

- Pregnancy