| Objectives:To examine the accuracy in using 99mTc-MIBI quantitative gated myocardial perfusion SPECT (Germane method) to evaluate the viable myocardium after acute myocardial infarction; and also examine the effectiveness of coronary artery bypass grafting and Salvage PTCA/Stent in treating acute myocardial infarction with non-patency on obstructed coronary arteries after intravenous thrombolytic therapy.Methods:66 patients (with non-patency on obstructed coronary arteries after rt-PA50mg intravenous thrombolytic therapy) are divided into two groups. The coronary artery bypass-grafting group (n=32) had bypass grafting within 7.6+2.2hrs after experiencing the symptoms of acute myocardial infarction, either great saphenous vein grafting together with internal mammary arteries grafting applied or only saphenous vein grafting applied, with 2.4+1.1 grafts to each patient in average. All patients were under general anaesthesia, 21 of them were under extracorporeal circulation below normal temperature and 11 were at normal temperature.The Salvage PTCA/Stent (n=34) group had patency on previous obstructed coronary artery within 6.8+3.6 hrs after experiencing the symptoms of acute myocardial infarction. All obstructive vessels had been placed with a stent.Both groups undertook coronary arteriography 90mins after being injected with 99mTc-MIBI 740mBq before or during the procedure of thrombolysis inmyocardial infarction simultaneously, and also undertook 99mTc - MIBI quantitative gated myocardial perfusion SPECT (Germano method) prior angiography and 30 days after the operation. The following set of data was obtained prior and after the operation and the variation was measured: the semi-quantitative score of myocardial 99mTc-MIBI uptake, the segments of regional ventricular wall motion abnormality, LVEF, EDV, ESV.Results:Two deaths occurred after coronary artery bypass grafting presenting mortality of 6.2%, one death after Salvage PTCA presenting mortality of 2.9%, four cases with vessel re-infarction with the re-infarction rate of 11.4%.Within the coronary artery bypass grafting group, the results of the following data indicated significant improvement (P<0.05) prior and after the operation: semi-quantitative score of myocardial 99mTc桵IBI uptake, the segments of regional ventricular wall motion abnormality, LVEF and ESV while no signification improvement found in EDV. Furthermore, the improvement in semi-quantitative score of myocardial 99mTc-MIBI uptake was as great as 58.9% while to the Salvage PTCA group was 52.4%.Within the Salvage PTCA/Stent group, significant improvement in the semi-quantitative score of myocardial 99mTc-MIBI uptake, LVEF and ESV prior and after the operation was also found, while no significant improvement was found in the segments of regional ventricular wall motion abnormality and EDV.Prior the operation, 166 segments awarded the myocardial perfusion images scores of 3-4 within these both groups, among them, 17 segments appearedno ventricular regional wall motion myocardial perfusion; 95 i egments with systolic functions (decrease of systolic functions included). After the operation, nine of those segments with no ventricular regional wall motion myocardial perfusion and 65 of those segments with systolic functions have indicated substantial improvement of myocardial perfusion. In consideration of the figures from both myocardial perfusion images scores and ventricular regional wall motion myocardial perfusion, 99mTc桵IBI provided accuracy rate of 77.2% (71/92) in diagnosing myocardial infarction segments.Conclusions:1. 99mTc-MIBI quantitative gated myocardial perfusion SPECT (Germano method) is a technique to continuously monitor the changes of myocardial perfusion and the function of left ventricular after acute myocardial infarction from the perspectives of dynamic, quantitative and deterministic nature; and to relatively accurately measure the viable myocardial. This technique provides objective indicators for clinical assessment on t...
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