SEATTLE, June 19 -- Real-time perfusion imaging during dobutamine stress echocardiography can identify asymptomatic diabetic patients at risk of clinical events from occult coronary artery disease, researchers found.
Patients who had either myocardial perfusion defects or wall motion abnormalities had a significantly lower event-free survival (P<0.001 and P=0.004, respectively) compared with patients who had normal echo studies, Saritha Dodla, M.D., of the University of Nebraska in Omaha, reported at the American Society of Echocardiography meeting here.
Perfusion defects in the absence of wall-motion abnormalities also identified patients at risk of clinical events, Dr. Dodla and colleagues found.
"Conventional heart ultrasound evaluates wall motion abnormalities," said Dr. Dodla. "Real-time perfusion echocardiography looks at blood flow into the heart muscle, thereby increasing the accuracy of the stress test. We think this test is better than what is in clinical practice right now."
The researchers evaluated 149 consecutive patients with type I or type II diabetes who showed no symptoms of coronary artery disease. None of the patients had a history of CAD, coronary revascularization, chest pain, dyspnea, or resting segmental wall motion abnormalities on baseline echocardiography. All of the patients had a normal resting ejection fraction that averaged 58%.
Segmental myocardial perfusion and wall motion in three coronary-artery territories were analyzed at rest and during peak dobutamine stress. Myocardial perfusion and contrast-enhanced wall motion abnormalities were interpreted by means of a 17-segment model.
Abnormal perfusion was defined as a defect in contrast enhancement in two or more contiguous segments. Abnormal wall motion was defined as abnormalities in two contiguous segments.
The patients were followed for a median of 23 months for coronary events (nonfatal myocardial infarction, death, or the need for urgent revascularization).
Inducible perfusion defects were identified in 25 patients; 12 patients had inducible wall-motion abnormalities.
Patients with perfusion defects had an event-free survival of 72% versus 98% in patients with normal perfusion responses (P<0.001). The presence of wall-motion abnormalities was associated with a 67% event-free survival, compared with 96% among patients with normal wall motion (P=0.004).
Thirteen patients had abnormal perfusion but normal wall motion. Three of those patients had nonfatal myocardial infarctions during follow up.
"Real-time perfusion imaging during dobutamine stress testing is a promising technique to detect occult CAD in asymptomatic diabetic patients," Dr. Dodla concluded.
"Use of this technique during preoperative risk stratification will help identify patients at risk for perioperative cardiovascular complications. This method also can be used for primary prevention, enabling early detection of CAD and decreasing the risk of cardiovascular events."
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