Can CT Angiography Predict the Future Risk of Patients With Chest Pain?

CT Angiography can help to predict the risk of future cardiac events better than those missed by functional testing.

The presence and extent of coronary artery disease detected by CT angiography could help to predict the risk of future cardiac events than did the measures of exercise tolerance or restricted blood flow to the heart muscle, finds a study result from Massachusetts General Hospital.//

The analysis of diagnostic test results from the Prospective Multicenter Imaging Study for Evaluation of Chest Pain (PROMISE) trial showed that patients with stable chest pain were randomized to anatomic or functional testing as initial diagnostic strategy.

CT Angiography Can Hasten the Diagnosis of Heart Ailments
Recently coronary computed tomography angiography has emerged as an effective diagnostic tool to image the coronary arteries. Prof. Hoffmann analyzed its effectiveness against the standard protocol.

‘CT angiography appears to be better at predicting the future risk of patients with chest pain when compared to those missed by functional testing.’

The superiority of CT angiography primarily depended on its ability to reveal nonobstructive coronary artery disease. The report by a team led by Udo Hoffmann, MD, MPH, of the Massachusetts General Hospital (MGH) appears in the June 13 issue of Circulation.

"We do show that obstructive coronary artery disease and myocardial ischemia remain the strongest predictors of future cardiovascular events, but for the first time, in a randomized comparison we demonstrate the ability of CT angiography (CTA) to identify a large group of at-risk patients who would have been missed by functional stress testing," says Hoffmann, who is director of the MGH Cardiac MR PET CT Program.

"This not only provides important information for physicians making choices regarding which test to perform but also suggests that implementing lifestyle changes and potentially the use of statin drugs may lower the risk of future clinical events for patients with nonobstructive disease."

CT Angiography Allows Safe Discharge of Patients With Possible Acute Coronary Syndrome from the Emergency Department
The use of CCTA in low-to-intermediate-risk patients with coronary ailments in the emergency department is effective in reducing their hospital stay by facilitating their early discharge.

The PROMISE trial was conducted at 193 centers across North America to determine whether a care strategy starting with coronary CTA, which reveals the structure of blood vessels supplying the heart, or a strategy starting with functional testing, measures such as stress testing or echocardiography that reflect how well the heart muscle is working, provided better guidance for clinical decisions regarding patients with chest pain.

Those results, reported in a 2015 New England Journal paper, found similar outcomes for both strategies in terms of the incidence of future cardiovascular events.

Computed Tomography Scan (CT Scan)
Computed Tomography (CT) scan is a type of medical examination that uses X-rays and computer processing to create sectional images of the body to provide more efficient results than X-rays.

The current study directly analyzed associations between the results of all diagnostic tests and the risk of future cardiac events in around 9,100 of the more than 10,000 patients in the PROMISE trial. The most important result indicated that the ability of coronary CTA to identify nonobstructive coronary artery disease - a less-than-70-percent narrowing of a coronary artery - identifies an at-risk group of patients not found by functional testing.

In fact, most of the cardiovascular events during the study's two-year follow-up period occurred in patients not initially diagnosed with coronary artery obstruction.

CT Angiography can Identify Disease and Injury Beyond Pulmonary Arteries
Computed tomography angiography (CTA) can identify abnormalities and injury beyond the pulmonary arteries, including broken bones and heart disease, according to a study.

While functional testing on its own was inferior to CTA, combining the results of functional testing with traditional cardiovascular risk factors - such as cholesterol levels, blood pressure and smoking status - significantly improved its prognostic value.

"While these observational data cannot prove that treating patients based on the results of CTA testing will automatically result in better health outcomes, they do provide new information enabling a more informed choice of testing for patients with stable chest pain, especially for predicting future cardiovascular risk." says Hoffmann, who is a professor of Radiology at Harvard Medical School.

"Future studies also need to determine whether more detailed analysis of exercise parameters in functional testing could improve its prognostic ability; but it's reassuring that both strategies can provide important prognostic information for patients and their physicians."

Source-Eurekalert