Patients with chest pain often receive either a computed tomographic angiography (CTA) or a functional stress test to detect whether their chest pains and shortness of breath are caused by a blocked blood vessel or not. CTA is a CT scan that uses fast imaging with intravenous dye to show blockages of the coronary arteries, while the stress test includes exercise along with an electrocardiogram monitor, echocardiography or nuclear image to ascertain heart function and blood flow. Duke Medicine researchers have now revealed that the rates of heart attacks and other major cardiac events within two years were similar irrespective of whether the symptomatic patients were evaluated with CTA or the traditional stress test.
The PROMISE study enrolled 10,003 patients at 193 centers in North America to determine whether one approach ultimately led to better outcomes. Study participants were randomly assigned to receive either a computed tomographic angiography (CTA) or a functional stress test. Researchers found that compared to functional stress test, CTA did not reduce the incidence of heart attacks, hospitalizations for unstable angina, major procedural complications or death over a median of 25 months of follow-up. Findings suggest that CTA posted a statistical advantage in the first year of the study in reducing heart attacks and death, but it was not sustained over the second year. Death, heart attacks or other serious heart events occurred in 3.3% of CTA patients and 3% of functional stress test patients across the 25-month follow-up period.
However, there were indications that CTA may have accurately guided patients to more appropriate follow-up testing. Among patients who had CTA, 3.4% received invasive catheterization that then determined they were actually free of disease, compared to 4.3% of patients getting the stress test. Manesh Patel, M.D., director of Interventional Cardiology at Duke University Health System, said, "These findings are important as they indicate that a CTA testing strategy can better triage patients to the cardiac catheterization lab. And it will increase the likelihood that we can improve patient outcomes." Cumulative radiation exposure was also found to be lower for patients who received CTA compared to nuclear imaging.
Lead author Pamela Douglas, M.D., Geller Professor of Research in Cardiovascular Diseases at the Duke Clinical Research Institute, said, "The strength of our study is that it provides a real world assessment of how testing in patients with chest pain has an impact on the subsequent health of patients with chest pain. We have had very little high-quality evidence to guide decision-making for how best to evaluate these patients. This study provides new assurance for patients and their physicians that both methods result in low rates of serious outcomes, around 3% over two years, and that's great news."
Udo Hoffmann, M.D., principal investigator of the PROMISE Imaging Core and Professor of Radiology at Harvard Medical School and Director of Cardiovascular Imaging at Massachusetts General Hospital, said, "PROMISE establishes CTA as a viable alternative to stress testing for the evaluation of patients with suspected coronary disease. With the addition of high-risk plaque assessment and CT fractional flow reserve technology on the horizon, we may have yet to see the full potential of CTA."
The study was presented at a meeting of the American College of Cardiology and appear online in 'The New England Journal of Medicine'.