Detection of the viable myocardium. A perfusion scintigraphic study, before and after coronary bypass surgery in myocardial infarction patients

Willliam A. Chalela, Paulo J. Moffa, José A. F. Ramires, Aguinaldo P. Moraes, José Soares Jr, José C. Meneghetti
1999 Arquivos Brasileiros de Cardiologia  
Objective -To compare single-photon-emission computed tomography (SPECT) imaging scans using 201 Tl and 99m Tc-MIBI in detection of viable myocardium, in regions compromised by infarction. Methods - Thirty-two (59.3±9.8 years old and 87% male) myocardial infarction patients were studied. All had Q waves on the ECG and left ventricle ejection fraction of <50%. They underwent coronary and left ventricle angiographies and SPECT before (including 201 Tl reinjection) and after coronary artery bypass
more » ... onary artery bypass surgery (CABG). Improvement in perfusion observed after surgery was considered the gold standard for myocardial viability. Results -Among 102 studied regions of the heart, there were 40 (39.2%) areas of transient perfusion defects in the conventional protocol with 201 Tl and 52 (51.0%) after reinjection. Therefore, 12/62 (19.4%) more viable regions were identified by reinjection. Using 99m Tc-MIBI, only 14 (13.7%) regions with transient defects were identified, all of which were seen also in 201 Tl protocols. After surgery, 49 of a total of 93 regions analyzed (52.7%) were viable. Sensitivity, specificity, accuracy, positive and negative prediction values were, respectively, 201 90.9%, 77.4%, 88.9% and 70.2%, 81.8%, 81.7%, 83.3% and 80.0%; 90.9%, 53.8%, 71.4% and 50.6%. Logistic regression demonstrated that the reinjection protocol with 201 Tl was the best predictor of viability (P<0.001). Conclusion -Our data suggest the election of 201 Tl for viability studies, especially when using the reinjection protocol.
doi:10.1590/s0066-782x1999000500001 pmid:10668224 fatcat:rdvp4gf37ncwbeomirisc5a5xe