Advances in imaging could help predict, prevent heart attacks
For decades, cardiologists have known that most heart attacks are not triggered by large, stable blockages in the coronary arteries. Instead, the culprit is often smaller plaques that suddenly rupture with little warning. These vulnerable plaques are lipid-rich, inflamed deposits with thin fibrous caps that suddenly break open and trigger clot formation.
Detecting these dangerous plaques before they rupture is now becoming possible, James Muller, MD, a cardiologist at Brigham and Women’s Hospital and senior lecturer at Harvard Medical School, told Cardiovascular Business. Muller also co-founded the intravascular imaging companies Infraredx and SpectraWave.
“We introduced the concept in 1989 that there are hidden plaques in the artery wall that rupture and cause heart attack and sudden death,” Muller said. “After years of skepticism, the data have finally caught up. The controversy is over. Vulnerable plaques can be found.”
From theory to proven cardiovascular target
Muller’s pioneering work using near-infrared spectroscopy (NIRS) allows cardiologists to identify lipid-core plaques inside coronary arteries. Early studies suggested NIRS could detect these rupture-prone lesions, but detractors questioned whether they truly caused future events.
That debate, Muller said, has now been settled. “Eight independent studies have shown that baseline measurements of suspected vulnerable plaques predict future adverse outcomes. We can now characterize the stages of coronary disease ... and know which ones are most dangerous,” he said.
Expanding plaque detection from the cath lab to the CT suite
While intravascular imaging remains the gold standard, Muller sees enormous potential in AI-enhanced coronary CT angiography (CCTA) as a noninvasive screening tool. Companies such as Heartflow and Cleerly have gained FDA clearance and reimbursement for software that analyzes plaque composition and identifies high-risk, low-density regions that may represent vulnerable plaques. This enables CCTA scans to act as a roadmap to preplan procedures and get a more precise patient risk score.
"Coronary disease is the world's leading cause of death and we don't have a good screening method. I have patients that come and say, 'What can I do?' And I can do a stress test that'll look at stenosis, but that will not find vulnerable plaques that are not stenotic. So you can get your LDL checked and that tells you something, but it's not a great predictor. So we lack what prostate has, what breast cancer has with mammograms ... we lack a easily applicable screening test, and it looks like CT is going to be that, because half of coronary events occur in people with no prior coronary disease," Muller explained.
He said in order to prevent 300,000 sudden deaths a year in the United States, there needs to be a better screening system. Muller said it looks like CT with an AI-enabled analysis of the images may be the solution.
He envisions a workflow in which CT scans serve as a first-line assessment, guiding whether patients should be referred for invasive imaging or procedures.
The next frontier may be treating plaque before it ruptures
With detection advancing, attention is turning toward how best to stabilize or eliminate vulnerable plaques. The logical next step once you can find vulnerable plaques is to decide how to treat them safely. Muller noted that several treatment technologies are being studies, including next-generation bioadaptive stents, drug-coated balloons, bioresorbable scaffolds and even cryotherapy to freeze unstable lesions.
“There's a whole field now developing of treatments for vulnerable plaque,” Muller said.
Recent clinical trials are testing whether treating these plaques preemptively can prevent heart attacks. Muller highlighted the PREVENT study, led by researchers in South Korea and presented at ACC.24, as a turning point. In that study, patients with non-obstructive, vulnerable plaques were randomly assigned to either receive a stent or medical therapy alone. After seven years, those who received stents had significantly fewer major adverse cardiac events, including death, myocardial infarction, and repeat revascularization.
"So now we have more than a diagnostic study. We have a treatment study. Diagnosis in medicine is often harder than treatment ... I think 80% of the journey was, can we find the darn things? Now the remaining 20% is ... do they need local treatment?" Muller explained.
He said that answer is probably yes, and that there are four ongoing trials now looking at the stenting of non-stenotic vulnerable plaques to see if that lowers the risk of future heart attacks.
Dave Fornell has covered healthcare for more than 17 years, with a focus in cardiology and radiology. Fornell is a 5-time winner of a Jesse H. Neal Award, the most prestigious editorial honors in the field of specialized journalism. The wins included best technical content, best use of social media and best COVID-19 coverage. Fornell was also a three-time Neal finalist for best range of work by a single author. He produces more than 100 editorial videos each year, most of them interviews with key opinion leaders in medicine. He also writes technical articles, covers key trends, conducts video hospital site visits, and is very involved with social media. E-mail: [email protected]