Researchers found that myocardial perfusion test with gated SPECT was a more accurate predictor of prognosis in chronic ischemic heart disease (IHD), compared to the capability of other medical techniques to determine the extent of heart disease and stratify patients, according to a study in the April issue of the Journal of Nuclear Medicine.
Researchers selected a group of patients with known or suspected--albeit stable--IHD. Those participants with previous coronary artery bypass surgery, chronic kidney failure and hyperthyroidism were excluded, leaving 492 study subjects between the ages of 55 and 75. Each subject underwent a complete diagnostic work-up that included a medical history, physical examination, blood tests, electrocardiography at rest, 2D echocardiography and gated SPECT after stress and at rest. Patients also underwent coronary arteriography, which is currently the standard clinical procedure for diagnosing IHD, according to the American Heart Association.
During the next 37 months, researchers said that patients returned for periodic exams in an outpatient setting. Based on these data, the researchers determined that of the techniques investigated--including coronary arteriography--gated SPECT is the best predictor of future cardiac events.
"The prognostic value of stress testing with MPI has been investigated for several years," said Alessia Gimelli, MD, at the Clinical Physiology Institute CNR, G. Monasterio Foundation in Pisa, Italy. "However, substantial changes in nuclear cardiology have occurred over the past two decades that have led to improved techniques. The clinical profile of patients with IHD has also changed, with patients often being older and affected by more diseases than in the past. We were therefore surprised to see that gated SPECT remains the best predictor of future cardiac events in patients with IHD."
Although left ventricular ejection fraction is more commonly used in clinical practice to predict patient outcome, this study revealed that the extent of damage to the heart muscle--as shown in the SPECT images--is a better prognosticator of how patients will fare, according to the authors. The ability to identify individuals at risk for future cardiac events, such as heart attacks, has considerable appeal because the early initiation of preventive therapies may alter the course of the disease, noted the researchers.
"Risk stratification allows us to categorize patients according to the severity of their disease and risk of future cardiac events," said Gimelli. "As a result, we are able to allocate resources where needed and treat the sickest patients more aggressively."