Technetium-99m sestamibi for the assessment of myocardial salvage following reperfusion therapy in acute myocardial infarction.
BACKGROUND
Reperfusion therapy with either thrombolysis or angioplasty has been shown to be beneficial in acute myocardial infarction. Tc-99m sestamibi is a myocardial tracer that can be used to assess myocardial salvage because of its property of very limited redistribution.


METHODS
To assess the feasibility of this technique locally, Tc-99m sestamibi was injected before and after reperfusion therapy with angioplasty (n = 11) or streptokinase (n = 18) in 29 patients with acute myocardial infarction (anterior = 25, inferior = 4). Single-photon emission computed tomography (SPECT) was performed within 4 hours of reperfusion and repeated 5 to 7 days later.


RESULTS
Initial perfusion defect size ranged from 6% to 78% (mean 36.3 +/- 18.7%), and final defect size from 0% to 50% of the left ventricle (mean 23.7 +/- 14.8%, P < 0.001). Patients with proximal left anterior descending artery (LAD) lesions had larger defects compared to those with mid LAD lesions (mean defect size 52% for pLAD versus 28% for mLAD, P < 0.013). However, there were wide variations in initial defect size (myocardium at risk) for a given infarct-related artery location. The mean decrease in defect size was 12% in the 28 patients with patent arteries compared to only 2% in the patient with an occluded artery (47% to 45%). There was no significant difference in amount of salvage between patients who had thrombolysis (mean 13%, P = 0.0003) and patients who had percutaneous transluminal coronary angioplasty (PTCA) (mean 12%, P = 0.005).


CONCLUSIONS
Assessment of myocardial salvage is feasible using Tc-99m sestamibi SPECT imaging. It allows for quantitation of myocardium at risk and the amount of myocardial salvage, which is not possible by angiography alone.
Keng
F Y
FY
Department of Cardiology, National Heart Centre, Singapore.
Chua
T S
TS
Goh
A S
AS
Ang
E S
ES
Sundram
F X
FX
Tan
A T
AT
D000328:Adult; D000368:Aged; D015906:Angioplasty, Balloon, Coronary / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy*; D015425:Myocardial Reperfusion / Q000379:methods; D011336:Probability; D016879:Salvage Therapy; D012680:Sensitivity and Specificity; D013300:Streptokinase / Q000627:therapeutic use*; D017256:Technetium Tc 99m Sestamibi; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
D005343:Fibrinolytic Agents; D017256:Technetium Tc 99m Sestamibi; D013300:Streptokinase