SPECT can identify which patients would benefit more from undergoing percutaneous coronary intervention (PCI) than receiving therapy alone for blocked coronary arteries, according to late-breaking trial results presented at the American Heart Association (AHA) conference in Orlando, Fla., this week.
Myocardial perfusion SPECT (MPS) assesses blood flow in the heart by taking nuclear images of the chest after injecting a radioactive tracer into the blood.
In the nuclear sub-study of the Clinical Trial Outcomes Using Revascularization and Aggressive Drug Evaluation (COURAGE) trial, researchers found that MPS imaging could help identify the patients more likely to benefit from percutaneous coronary intervention (PCI), or angiography.
The COURAGE trial, which was conducted between 1999 and 2004, examined 2,287 patients in 50 U.S. and Canadian centers. The researchers compared outcomes from a follow-up period ranging from 2.5 to seven years. In the sub-study of the original trial, the researchers used SPECT imaging to inspect the hearts of 313 patients.
Bristol Myers-Squibb and Astellas Healthcare funded the study.
Images were taken of the two patient groups prior to and after they underwent treatment for coronary artery disease. One group received optimal medical therapy (OMT) along with angioplasty, and the other group received OMT alone.
“Our outcomes in this sub-study don’t change the main COURAGE trial results,” according to Leslee Shaw, PhD, principal investigator of the nuclear sub-study and a professor of medicine at Emory University in Atlanta.
The researchers found no differences in rates of death, heart attack, stroke or hospitalization for acute coronary disease between the patients who underwent PCI and those who only received OMT.
Shaw said the study clarifies “care for a certain subset of stable chest pain patients who have stress-induced ischemia prior to treatment. This group of patients benefited from PCI and had a greater reduction in ischemia by one year. The main effect this could have on clinical practice is that patients with ischemia may be more referred to PCI for ischemia resolution.”
Overall, the groups were similar, including the anginal class, level of ischemia and the number of patients who had multiple diseased vessels.
In follow-up imaging, treatment reduced ischemia by 2.7 percent in patients who received PCI with OMT; OMT-only patients only had a 0.5 percent reduction. The SPECT images showed that patients had a significant heart muscle recovery (more than 5 percent); 33 percent of patients with PCI and OMT showed a reduction in ischemia of 5 percent or more, compared with 19 percent of OMT-only patients. With patients who had reduced ischemia, nearly 80 patients of both groups were angina free. However, in patients who began the study with high-risk ischemia (those with more than 10 percent of their heart muscle compromised), treatment with PCI and OMT were more commonly effective in reducing ischemia than OMT alone.
Shaw said that “statin therapy was similar therapy between the two groups.”
The researchers concluded that “PCI added to OMT resulted in greater reduction in ischemia when compared to OMT alone.” In fact, Shaw noted a 5 percent reduction in ischemic assessment, confirming the value of using MPS.
In response to a question about the current political trend against reimbursements, Shaw said that “approximately half of the sites in the study use imaging as part of their treatment. Some form of ischemic assessment was performed in each of the centers and that is hard to reverse.”