ALTERED MYOCARDIAL PERFUSION DURING DOBUTAMINE STRESS-TESTING IN SILENT VERSUS SYMPTOMATIC MYOCARDIAL-ISCHEMIA ASSESSED BY QUANTITATIVE MIBI SPET IMAGING

The aim of the study was to compare the extent and severity of reversi ble underperfusion in silent versus painful myocardial ischaemia durin g the dobutamine stress test. A consecutive series of 85 patients with significant coronary artery disease and reversible perfusion defects on technetium-99m methoxyisobutylisonitrile single-photon emission tom ography performed at rest and during high-dose dobutamine stress (up t o 40 mu g kg(-1) min(-1)) were studied. The left ventricle was divided into six segments. An ischaemic perfusion score was derived quantitat ively by subtracting the rest from the stress defect score. Patients w ith multivessel disease had a higher ischaemic score (610+/-762 vs 310 +/-411, P<0.05) and a higher number of reversible perfusion defects (2 .1+/-1.2 vs 1.1+/-0.8, P<0.01) than patients with single-vessel diseas e. Typical angina occurred in 37 patients (44%) during the test. There was no significant difference between patients with and patients with out angina with respect to age, gender, peak rate-pressure product, pr evalence of previous myocardial infarction, diabetes mellitus, multive ssel disease or number of stenotic coronary arteries. Stress, rest and ischaemic scores as well as the number and distribution of reversible defects were not different in patients with and patients without angi na. Patients with angina more frequently had a history of typical angi na before the test (43% vs 17%, P<0.01) and ST-segment depression duri ng the test (54% vs 25%, P<0.01). It is concluded that in patients wit h coronary artery disease and ischaemia detected by dobutamine scintig raphy, the extent and severity of coronary artery disease and myocardi al perfusion abnormalities are similar with or without angina during s tress testing.