CT Angiography Aids in Predicting Heart Attack Risk

Coronary computed tomography angiography (CCTA) is an effective first-line test to determine heart attack risk and other adverse cardiac events in patients with suspected coronary artery disease - even if there are no treatable risk factors, according to a study published online in the journal Radiology.

CCTA is a noninvasive test that is highly accurate in diagnosis or exclusion of coronary artery disease, but it is most often used based on clinical risk factor scoring. Until this study, not much was known about the value of CCTA in patients with no medically modifiable risk factors, such elevated cholesterol, hypertension, diabetes, and smoking.

Currently, there are no risk models to help guide clinicians in identifying symptomatic patients without cardiac risk factors but who are at an increased risk of death and myocardial infarction because of non-modifiable risk factors such as family history. As a result, physicians are limited in their treatment options.

“This scenario, where patients are symptomatic but have no cardiac risk factors, comes up often in clinical practice,” lead author Jonathon Leipsic, MD, from the University of British Columbia, said in a release. “We lack a good tool to stratify these patients into risk groups.”

To address this lack of information, Leipsic and his team correlated CCTA findings with the risk of major adverse factors for 5,262 patients, culled from the Coronary CT Angiography Evaluation For Clinical Outomes: An International Multicenter (CONFIRM) registry. The average follow up was 2.3 years.

The researchers found that 104 patients had experienced a major adverse cardiovascular event, and that there was a high prevalence of coronary artery disease in the study group. More than 25 percent of the patients had non-obstructive disease or disease related to the buildup of arterial plaque. Twelve percent of patients had obstructive disease with more than 50 percent narrowing in a coronary artery.

Patients with narrowing of the coronary arteries on CT had a higher risk of adverse cardiac events, noted Leipsic. “This was true even for those without a family history of heart disease.”

Both symptomatic and asymptomatic patients with obstructive disease had a higher risk of a major cardiac event. Patients with no sign of cardiac disease as seen by CCTA, however, had a very low risk of a major event.

The study’s findings are important because patients have only vague symptoms but have no medically modifiable risk factors may not be followed as closely as they should, increasing their risk of experiencing a major event or death. Use of CCTA could solve this problem, says Leipsic.
The researchers are continuing their study of the CONFIRM data to see if there is more to be learned about the relationship between plaque and heart attacks and the longer-term outlook for patients with coronary artery disease.