A blood test in combination with a stress test can help better determine if someone is likely to have a blocked heart artery, according to a study by doctors at Providence Hospital in Southfield, Mich. The study was presented today at the 2005 American College of Cardiology's Scientific Session in Orlando.
The blood test measures the level of myeloperoxidase or MPO, in the bloodstream. MPO is an enzyme released by disease-fighting white blood cells. In a study of 83 patients, doctors found that when increased levels of MPO were present in people with an abnormal stress test, they were more likely to have a blocked artery.
"Previous research has shown us that elevated MPO levels can be an indicator for heart disease," says Shukri David, M.D., chief of cardiology at Providence Hospital.
"We believe this is the first study to show that when a stress test is abnormal and the MPO level is increased, the chances of having a blocked artery are also increased. While the study group was relatively small, the findings indicate that this could provide doctors with a better way to assess the presence of coronary artery disease and whether an invasive procedure is necessary."
29 patients in the study had a positive myocardial perfusion imaging stress test.
The test involves an injection of a small amount of radioactive material that circulates in the bloodstream to show if the heart muscle is receiving adequate blood supply. Using a coronary angiogram to reveal the extent and severity of blockages, doctors found that the 17 patients with significantly elevated MPO levels had a blockage that called for an immediate invasive treatment such as balloon angioplasty. The 12 patients with low levels of MPO did not have a significant blockage and were treated with medications.
People who have suffered a heart attack or those with a history or evidence of infections of any kind were excluded from the study.
Dr. David says the study also provided more evidence of the connection between obesity and heart disease. He says the obese patients in the study had significantly higher MPO levels. Providence Hospital is preparing to conduct a larger study regarding MPO levels and abnormal stress. The hospital is also involved in other research into MPO as a marker for heart disease.
Providence Hospital, a 459-bed teaching hospital, is a member of St. John Health, the leading provider of heart care in Michigan. The Providence Heart Institute offers complete, centralized cardiac diagnostic services including echocardiography, catheterization lab, recovery and cardiology support services in one unit, providing patients, families, staff and physicians a convenient, pleasant environment.