DOBUTAMINE-INDUCED HYPOPERFUSION WITHOUT TRANSIENT WALL-MOTION ABNORMALITIES - LESS SEVERE ISCHEMIA OR LESS SEVERE STRESS

Objectives. This study sought to compare the clinical characteristics, hemodynamic response and severity of ischemia in patients with corona ry artery disease and reversible perfusion defects on dobutamine 2-met hoxy isobutyl isonitrile (MIBI) single-photon emission computed tomogr aphy (SPECT) with or without transient wall motion abnormalities. Back ground. The occurrence of reversible perfusion defects without concomi tant wall motion abnormalities in patients with coronary artery diseas e was attributed to less severe ischemia. However, little data are ava ilable to support this observation. Methods. Fifty-four consecutive pa tients with significant coronary artery disease and reversible perfusi on defects on dobutamine (up to 40 mu g/kg body weight per min) MIBI S PECT were studied (mean [+/-SD] age 59 +/- 11 years; 38 men, 16 women) . All patients underwent simultaneous echocardiography. The myocardium was divided into six matched segments, and ischemic perfusion score w as quantitatively derived in myocardial segments with reversible defec ts. Results. New or worsening wall motion abnormalities occurred in 40 patients (74%) (group A) and were absent in 14 (26%) (group B), There was no significant difference between the two groups with respect to age, previous myocardial infarction, number of abnormal coronary arter ies (1.8 +/- 0.8 vs. 1.6 +/- 0.9), number of reversible perfusion defe cts (1.6 +/- 0.9 vs, 1.8 +/- 0.7) or ischemic perfusion score (412 +/- 750 vs, 526 +/- 553). Patients in group A had a higher prevalence of male gender (80% vs, 43%, p < 0.01), higher peak systolic blood pressu re (147 +/- 30 vs. 127 +/- 31 mm Hg, p < 0.05), higher peak rate-press ure product (19,632 +/- 4,081 vs. 16,939 +/- 4,344, p < 0.01) and a hi gher prevalence of angina (53% vs. 14%) and ST segment depression (55% vs. 14%) than group B (p < 0.05 for both). Conclusions. In patients w ith coronary artery disease and ischemia on dobutamine MIBI SPECT, the absence of transient wall motion abnormalities is associated with a s imilar extent and severity of reversible perfusion defects, a lower st ress rate-pressure product and a higher prevalence of female gender th an patients with transient wall motion abnormalities. Mechanically sil ent ischemia should not be regarded as a marker of less severe ischemi a on myocardial perfusion scintigraphy.