AI-based imaging performs equally well as ultrasound in guiding heart procedures

Patients with narrowing of at least 50% in three major coronary arteries did equally well when treated with a minimally invasive stent placement guided either by ultrasound-based imaging or by a novel, artificial-intelligence-powered (AI), non-invasive imaging technique derived from angiography, researchers reported at the American College of Cardiology's Annual Scientific Session (ACC.25).

This is the first such study to be conducted in patients with angiographically significant lesions. Patients whose evaluation was non-invasively guided by the novel, AI-powered technique underwent approximately 10% fewer procedures, and their outcomes were comparable with those for patients whose evaluation was guided by a commonly used ultrasound-based imaging technique."

Jian'an Wang, MD, professor in the Heart Center at The Second Affiliated Hospital of Zhejiang University School of Medicine in Hangzhou, China, and study's senior author

The study, known as FLAVOUR II, met its primary endpoint, a composite of death, a heart attack or need for a repeat procedure at one year, Wang said.

Patients enrolled in the study had angiographically significant coronary artery disease in which three of the major arteries that supply blood to the heart become inflamed or partially blocked by cholesterol deposits, causing chest pain and shortness of breath.

Percutaneous coronary intervention (PCI, also known as coronary angioplasty) is a minimally invasive procedure in which tiny metal tubes called stents are inserted into partially blocked coronary arteries to prop them open. Fractional flow reserve (FFR) assessment, a technique for measuring blood pressure and flow in the partially blocked coronary arteries, is used to identify which patients would benefit most from PCI and which patients can safely continue to be treated with medication. Generally, patients with an FFR score of 0.80 or lower undergo PCI, while those with a score higher than 0.80 continue medication.

Conventional FFR assessment is performed by threading a wire or catheter through the body to the blocked coronary arteries to examine blood flow and pressure through these arteries. Although FFR assessment is helpful in identifying which patients are most likely to benefit from PCI, Wang said, technical and logistical challenges have limited its use.

In FLAVOUR II, Wang and his colleagues used a novel, AI-powered method of FFR assessment known as AngioFFR, which calculates FFR from a single-view angiogram (x-ray) of the coronary arteries. Compared with conventional FFR assessment, AngioFFR is non-invasive, simpler and less time-consuming to perform, Wang said.

The aim of FLAVOUR II, he said, was to determine whether outcomes for patients treated with AngioFFR-guided PCI were comparable with those of similar patients who received PCI guided by IVUS, which uses sound waves to view the extent of arterial narrowing and is the imaging technique used most often to guide PCI.

The study enrolled 1,872 patients (average age 65 years, 68% men) at 22 medical centers in China. To be eligible for the study, patients had to have narrowing of at least 50% in three major arteries, but no significant narrowing in the left main coronary artery. Most patients had at least one co-existing condition: 67.6% had high blood pressure, 31% had diabetes, 66.9% had high cholesterol, 24.3% had chronic kidney disease, 25% were current smokers and 13.9% had previously had a heart attack.

Patients were randomly assigned to undergo either AngioFFR-guided or IVUS-guided PCI. In the AngioFFR group, PCI was performed if the AngioFFR score was 0.80 or below. In the IVUS group, PCI was performed if the narrowest part of the blood vessel was between three and four millimeters wide and the "plaque burden" (a measure of the amount of plaque in the most severely narrowed cross-section of an artery) was above 70%.

At the one-year follow-up, 73.9% of patients who received AngioFFR were treated with PCI, compared with 83.1% of those who received IVUS. In the AngioFFR group, 6.3% of patients experienced a composite of death, a heart attack or the need for a repeat procedure at one year compared with 6.0% in the IVUS group, a difference that was not statistically significant. Similar clinical outcomes were seen between the two groups in the occurrence of each component of the primary endpoint (i.e., death, heart attack or need for a repeat procedure), or in any patient subgroups, such as those with diabetes.

Wang and his colleagues plan to follow the patients enrolled in the study for at least five years to evaluate whether any differences in long-term effectiveness emerge between the two groups.

The study has limitations, Wang said. While the patients enrolled had angiographically significant lesions, they did not have complex lesions that are more difficult to treat with PCI. In addition, because the study was conducted in a single country, China, its patient population lacked diversity.

This study was simultaneously published online in The Lancet at the time of presentation.