CT fractional flow reserve (CT-FFR) imaging identifies patients with coronary artery blockage or narrowing who could benefit from revascularization -- and helps reduce the unnecessary use of invasive procedures, researchers have found.
A team led by Mangun Kaur Randhawa, MD, of Massachusetts General Hospital in Boston reported that individuals with significant narrowing and/or blockages identified on coronary CT angiography (CTA) who underwent CT-FFR had lower rates of invasive coronary angiography and ensuing percutaneous coronary intervention than patients who were not referred for a CT-FFR. The research was published April 11 in Radiology: Cardiothoracic Imaging.
"In patients with moderate narrowing or blockage of the arteries, there can be ambiguity about who would benefit from invasive testing and revascularization procedures," Randhawa said in a statement released by the RSNA. "CT-FFR helps us identify and select those patients who are most likely to benefit."
Coronary CTA is the go-to exam for diagnosing narrowed or blocked arteries in the heart, and it produces a score from mild blockage (0-1) to moderate (2-3) to severe (4-5). Individuals with scores above 3 tend to need medical interventions such as revascularization via stents or surgery to restore blood flow to the heart, the authors noted. Furthermore, clinicians have tended to use invasive coronary angiography and fractional flow reserve to assess blockages in the heart, but these tests don't always reliably predict the amount of blood flow in the vessel being evaluated.
That's why CT-FFR could help. It's a relatively new alternative to these invasive tests that can model coronary blood flow using CTA images of the heart, AI algorithms, and/or computational fluid dynamics, according to Randhawa's team.
The investigators assessed the impact of CT-FFR on the use of more invasive testing for heart blockages in a cohort of 2,985 patients who underwent CTA between August 2020 and August 2021. Of these, 284 (9.5%) were referred for CT-FFR analysis, and most of these referrals were due to patients having a CTA score of 3 or higher.
The group reported the following:
- 56.3% of the 284 patients had a negative CT-FFR result of > 0.8.*
- 30.9% of patients had abnormal results of ≤ 0.75.
- 12.6% of patients had a borderline result between 0.76 and 0.8.
Patients with considerable narrowing/blockages on coronary CTA who underwent CT-FFR had lower rates of invasive coronary angiography and lower rates of subsequent percutaneous coronary intervention compared with those who did not.
| Results of use of CT-FFR on rates of further invasive procedures in patients with considerable narrowing/blockages on coronary CTA | ||
|---|---|---|
| Procedure | Patients who did not undergo CT-FFR | Patients who did undergo CT-FFR |
| Invasive coronary angiography | 74.5% | 25.5% |
| Percutaneous coronary intervention | 78.9% | 21.1% |
When coronary artery flow is measured with CT-FFR, fewer patients require further investigation, senior author Brian Ghoshhajra, MD, academic chief of cardiovascular imaging at MGH, said in the RSNA statement.
"CT-FFR helps us identify patients who would most benefit from undergoing invasive procedures and to defer stenting or surgical treatment in patients who likely won't," he said.
The complete study can be found here.
*CT-FFR scores greater than 0.8 are normal, while scores between 0.76 and 0.8 are borderline, and 0.75 or less are abnormal.
