New coronary scan reduces need for invasive, artery-opening procedures, study finds

A newly developed, non-invasive scan that models coronary blood flow using images of the heart, AI algorithms and/or computational fluid dynamics can help identify which patients with coronary artery blockage or narrowing need angioplasty or a bypass procedure, a study published Thursday indicates. Photo by Sasin Tipchai/Pixabay

April 11 (UPI) -- A newly developed, non-invasive imaging test can help identify which patients with coronary artery blockage or narrowing need angioplasty or a bypass procedure, a U.S. study published Thursday shows.

The Massachusetts General Hospital research involving 284 patients who had undergone a traditional computed tomography angiography found that a non-invasive procedure that models coronary blood flow using CAT images of the heart, AI algorithms and/or computational fluid dynamics, was able to more accurately determine patients who would benefit from invasive tests and revascularization, according to a news release.

Published in the journal Radiology: Cardiothoracic Imaging, the retrospective study of what is called the CT-Fractional Flow Reserve protocol that assessed the impact of selective use of CT-FFR on clinical outcomes of patients who already had undergone coronary CTA at the hospital center between August 2020 and August 2021.

Their narrowing, or blockage severity scores, all were "moderate" to "severe" -- typically levels for which the medical indication is stents or revascularization surgery to restore blood flow to the heart -- but the follow up CT-FFR test was able to give the "all clear" to 160, or 56.3%, of the patients.

That compared with a "positive" indication to 88 patients, meaning medical intervention was required, and a borderline result for the other 36.

Only about one-fourth of patients with coronary CTA exams suggesting significant blockage or narrowing who subsequently underwent CT-FFR ended up having invasive coronary angiography, compared with three-fourths of patients not referred for CT-FFR.

The overall benefit was even more significant for the CT-FFR group with only 21.9% requiring a surgical procedure to insert stents to open narrowed coronary arteries, compared with 78.9% of the non CT-FFR group.

"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," said Dr. Mangun Kaur Randhawa, post-doctoral research fellow at MGH's Radiology Department in Boston.

"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. "CT-FFR helps us identify and select those patients who are most likely to benefit."

The novel CT-FFR boosts the efficacy of CT exams, explained the senior author, Massachusetts General associate chair for operations and academic chief of cardiovascular imaging, Brian B. Ghoshhajra.

But he stressed their results showed it yielded the greatest benefit when selectively employed.

"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," Ghoshhajra said.

He added that CT-FFR analysis was successful in the large majority of patients, regardless of challenging factors such as elevated or irregular heart rates and obesity.

"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," he said.

The study results demonstrate the clinical utility of CT-FFR when used selectively, the team said, highlighting its promise as a way to minimize safely the number of invasive procedures on patients with significant coronary artery narrowing or blockages.