“Coronary artery disease (CAD) can be reliably detected with CT, but it is unclear what the long-term clinical results are for patients with suspected CAD if the initial diagnosis is made with CT instead of cardiac catheterization,” Marc Dewey, MD, explains. “Cardiac catheterization is the standard method for diagnosing suspected CAD and allows for concurrent treatment. However, as an invasive examination, cardiac catheterization is associated with rare but serious complications.”

The DISCHARGE project investigated “whether CT is a safe alternative,” according to Dr. Dewey. The project was based on the single-center CAD-Man trial, which found CT to be “an accurate gatekeeper to cardiac catheterization that shortened length of stay outcomes,” he says

For a study published in The New England Journal of Medicine, Dr. Dewey and colleagues compared CT with cardiac catheterization as initial diagnostic imaging tools among 3,561 patients (56.2% women) with stable chest pain at 26 European centers. Major adverse cardiovascular events (MACE), including cardiovascular death, non-fatal myocardial infarction, and non-fatal stroke, over 3.5 years served as the primary outcome. Secondary outcomes included procedurerelated complications and angina pectoris.

Rate of MACE Comparable With CT Vs Cardiac Catheterization

“Clinical outcomes were similar in the CT group compared with the cardiac catheterization group,” Dr. Dewey notes. “MACE occurred in  2.1% of the CT group and 3.0% of the cardiac catheterization group. The frequency of major procedure-related complications was four times lower during initial management after CT compared with direct cardiac catheterization.”

Major procedure-related complications were reported in nine patients (0.5%) in the CT group and in 33 patients (1.9%) in the cardiac catheterization group (HR, 0.26; 95% CI, 0.13-0.55), according to the study results. More patients in the CT group (8.8%) reported angina in the final 4 weeks of follow-up than in the cardiac catheterization group (7.5%).

“There was no evidence of any difference in chest pain relief and improvement in QOL between the CT group and the cardiac catheterization group at follow-up,” Dr. Dewey says.

‘Convincing’ Results With Clinical Implications

Dr. Dewey notes that the high percentage of women in the trial—56.2%—is a “particularly important achievement,” as women have frequently been underrepresented in previous clinical trials. “While gender differences remain to be analyzed, the results of this study apply to both women and men,” says Dr. Dewey.

The trial was “a convincing study,” he continues. The results of the primary outcome, showing that clinical outcomes were similar between the CT group and the cardiac catheterization group, will influence clinical settings, according to Dr. Dewey.

“CT is a safe alternative to cardiac catheterization for patients with suspected CAD that will likely change clinical practice worldwide by replacing invasive testing with CT in patients with stable chest pain who can be expected to benefit,” he says.

Additional analyses of the DISCHARGE trial will examine how the clinical probability of CAD can be accurately estimated, according to Dr. Dewey, to understand if pre-test probability estimates can positively impact referral and indications for CT in routine clinical practice.

“Health economics are also an important component in making decisions about reimbursement in healthcare systems,” he says. “Further cost-effectiveness analyses of CT and cardiac catheterization that are methodologically very rigorous are necessary.”