A Cedars-Sinai and Amsterdam UMC-led team developed a machine learning system that analyzes quantitative plaque in coronary CTA exams to identify patients with ischemia and impaired myocardial blood flow (MBF), potentially creating an alternative to current methods.
The researchers trained the ML model using invasive FFR data from 254 patients (484 FFR vessels) to predict ischemia and impaired MBF by analyzing plaque data in CCTA exams.
They then tested it with CCTAs from 208 patients (581 vessels) who also underwent invasive FFR and H2O PET exams, finding that the CCTA ML scores:
- Predicted FFR-defined ischemia far more accurately than standard CCTA stenosis evaluations, while rivaling FFRCT assessments (AUCs: 0.92 vs. 0.84 & 0.93)
- Predicted PET-based impaired MBF more accurately than standard CCTA stenosis evaluations and FFRCT assessments (AUCs: 0.80 vs. 0.74 & 0.77)
Because the ML scoring system operates locally, the authors highlighted its potential to quickly assess high-risk patients before invasive coronary angiography (avoiding off-site processing delays) or to assess low-risk patients at earlier stages, helping to improve ICA efficiency and accuracy.
The researchers plan to continue to develop their CCTA plaque AI solution, including adding more plaque features and CCTA metrics, and potentially seeking regulatory approval depending on the results of future validation studies.
CCTA plaque AI is already one of the hottest segments on the commercial side of imaging AI, and this study highlights similar advances in academic centers, while showing that CCTA plaque AI can quickly and accurately predict both ischemia and lower MBF.
If it seemed like coronary imaging folks were more excited than usual last week, it’s because the AHA/ACC’s long-awaited chest pain guidelines just set the stage for a lot more imaging.
The Guidelines – The American Heart Association (AHA) and the American College of Cardiology (ACC) released their first clinical guidelines for the assessment and diagnosis of chest pain, outlining a range of new standards, processes, and pathways, while giving coronary imaging a central diagnostic role.
Front-Line Coronary CTA – The new guidelines made coronary CTA a front-line coronary artery disease test, assigning CCTA their highest recommendation level and proposing it for a large group of patients (mid-high risk of CAD, stable chest pain, <65yrs).
FFRct Next in Line – HeartFlow’s FFRct analysis will often serve as the next diagnostic step when CCTA exams reveal obstructive CAD (40-90% stenosis) or are inconclusive, with FFRct results either clarifying diagnosis or supporting treatment decisions.
Stress Imaging Pathways – The AHA/ACC guidelines also gave stress imaging (e.g. TTE, echo, CMRI, PET, etc.) their highest recommendation level, positioning stress imaging for more serious cases (likely or confirmed obstructive CAD, ≥65yrs) as well as for diagnosing myocardial ischemia and estimating risks of major cardiac events among patients with less severe cases (intermediate risk, no known CAD, acute chest pain).
Takeaway – These new guidelines are a big deal for coronary imaging, given the millions of people who show up at US emergency departments with chest pain each year. It’s also going to require some big changes across EDs, imaging centers, and radiology departments/practices, who will have to retool their imaging protocols/fleets and be able to expertly interpret a wave of coronary imaging exams (and handle a wave of incidentals).