Purpose: Preserved thrombolysis in myocardial infarction (TIMI) flow before percutaneous coronary intervention (PCI) in acute myocardial infarction is related to improved outcome. Gated single-photon emission computed tomography (SPECT) allows the simultaneous assessment of left ventricular perfusion and function. We evaluated the initial risk area and subsequent evolution of perfusion and function according to TIMI flow before successful primary PCI.
Methods: In 36 patients, treated with abciximab, primary PCI and stenting, 99mTc-sestamibi was injected before PCI and gated SPECT acquired thereafter. Gated SPECT was repeated 7 and 30 days later. Perfusion defect, wall motion score index, left ventricular ejection fraction and volumes were examined.
Results: Before PCI, 14 patients (group A) showed TIMI flow 2-3 and 22 (group B) TIMI flow 0-1, but no differences in clinical variables, initial risk area, wall motion score, ejection fraction or volumes. Perfusion defect was smaller in group A at 7 (9%+/-11% vs 19%+/-14%, p<0.02) and 30 days (7%+/-7% vs 16%+/-12%, p<0.02) and the salvage index was higher at 30 days (77%+/-22% vs 55%+/-28%, p<0.02). Wall motion score was lower in group A at 30 days (p<0.05). Ejection fraction significantly improved in both groups at 7 and 30 days. End-diastolic volume showed a trend towards a reduction in group A, whilst it was significantly increased in group B. Conversely, end-systolic volume was significantly decreased in group A but remained unchanged in group B.
Conclusion: In the setting of optimal myocardial reperfusion for myocardial infarction, preserved TIMI flow before PCI does not limit the initial risk area but it does improve myocardial salvage and functional recovery.