A recent study published in Radiology: Cardiothoracic Imaging has shown that a non-invasive imaging test called CT-FFR can help doctors identify patients with coronary artery blockage or narrowing who require revascularization procedures. This finding could potentially reduce the number of invasive procedures performed on patients with heart problems.
Understanding Coronary CT Angiography (CTA)
Doctors use coronary CT angiography (CTA) to diagnose narrowed or blocked arteries in the heart. The test receives a score from mild (0-1) to moderate (2-3) to severe (4-5), with patients scoring above 3 typically requiring medical treatments such as stents or surgeries to restore blood flow to the heart.
However, as Mangun Kaur Randhawa, M.D., a post-doctoral research fellow at Massachusetts General Hospital (MGH), explains, “CTA tells you the degree to which a vessel is blocked. But the degree of blockage doesn’t always reliably predict the amount of blood flow in the vessel.”
The Role of CT-FFR
CT-FFR (fractional flow reserve) is a relatively new alternative to invasive procedures like coronary angiography and invasive FFR. It non-invasively models a patient’s coronary blood flow using CTA images of the heart, AI algorithms, and/or computational fluid dynamics.
The Study
Dr. Randhawa’s research team conducted a retrospective study of 2,985 patients who underwent coronary CTA at MGH between August 2020 and August 2021. Of these patients, 284 were referred for CT-FFR analysis.
The study found that patients with significant narrowing/blockages on coronary CTA who underwent CT-FFR had lower rates of invasive coronary angiography (25.5% vs. 74.5%) and subsequent percutaneous coronary intervention (21.1% vs. 78.9%) compared to patients who were not referred for a CT-FFR.
Selective Use of CT-FFR
The study also showed that the benefits of CT-FFR were highest when used selectively, particularly in patients with moderate narrowing or blockage of the arteries (score of 3). Brian B. Ghoshhajra, M.D., M.B.A., associate chair for operations and academic chief of cardiovascular imaging at MGH, explains, “CT-FFR makes the CT ‘better’, but we found that the benefits were highest when used selectively.”
Successful Analysis Despite Challenges
The researchers found that their CT-FFR analysis was successful in the large majority of patients, regardless of challenging factors such as elevated or irregular heart rates and obesity.
Dr. Ghoshhajra adds, “When you objectively measure coronary artery flow with CT-FFR, you induce fewer patients to be further investigated and treated, because you tend to treat not just what the eyeball sees, but what the physiology supports.”
The study results demonstrate the utility of CT-FFR in clinical practice when used selectively, highlighting its potential to reduce the frequency of invasive procedures in patients with significant coronary artery narrowing or blockages without compromising safety. This non-invasive imaging test could help doctors make more informed decisions about which patients would benefit most from invasive procedures, potentially reducing unnecessary interventions and improving patient outcomes.
