Dobutamine stress echocardiography and technetium-99m-tetrofosmin/fluorine18-fluorodeoxyglucose single-photon emission computed tomography and influence of resting ejection fraction to assess myocardial viability in patients with severe left ventricular dysfunction and healed myocardial infarction

The purpose of this study was to compare 2 different techniques-dobutamine- atropine stress echocardiography (DSE) and dual-isotope simultaneous acquis ition (technetium-99-m-tetrofosmin/fluorine 18-fluorodeoxyglucose) single-p hoton emission computed tomography (DISA-SPECT)-for assessment of viable my ocardium. One hundred ten patients (mean age 55 +/- 9 years) with left vent ricular (LV) dysfunction (mean LV ejection fraction 27 +/- 13%) underwent b oth DISA-SPECT and DSE. A 16-segment scoring model was adopted for both tec hniques. Four types of wall motion during DSE were assessed: (1) biphasic, improvement at low dose (10 mu g/kg/min) with worsening at high dose; (2) w orsening deterioration without initial improvement; (3) sustained, persiste nt or late improvement; and (4) no change. Viability criteria were biphasic , worsening, and sustained improvement with DSE. Viability criteria with DI SA-SPECT were normal perfusion and metabolism (normal), concordantly mildly reduced perfusion and metabolism (subendocardial scar), or severely reduce d perfusion and increased metabolism (mismatch). Myocardium was considered nonviable with DSE in case of unchanged wall motion, or moderate reduction or absence in both technetium-99m-tetrofosmin perfusion and fluorodeoxygluc ose uptake with DISA-SPECT. Of 1,756 of 1,760 analyzable LV segments, 1,373 (78%) had severe wall motion abnormalities at baseline (severe hypokinesia , akinesia, or dyskinesia). Of these abnormal segments, 282 (21%) were cons idered viable during DSE (63 [5%] with biphasic response, 47 [3%] with isch emia, and 172 [13%]) with sustained improvement, whereas 1,091 (79%) were c onsidered nonviable. With DISA-SPECT, 396 (29%) segments were considered vi able (312 [23%] with matched perfusion/metabolism and 84 [6%] with mismatch ), whereas 977 segments (71%) were considered nonviable. Both techniques sh owed agreement for viability in 201 segments and 896 were concordantly clas sified as nonviable. Disagreement was present in 276 segments of which 195 (71%) were nonviable with DSE and viable with DISA-SPECT. Overall agreement between the 2 techniques was 81% (kappa 0.46) in a subgroup of patients wi th an ejection fraction <25% 78% (kappa 0.39). Thus, DSE and DISA-SPECT sho w good agreement for assessing viable myocardium not influenced by resting ejection fraction. DSE underestimated the amount of viable tissue compared with DISA-SPECT. (C) 1999 by Excerpta Medica, Inc.