Incidence and importance of thrombolysis in myocardial infarction grade 3 flow after primary percutaneous transluminal coronary angioplasty for acute myocardial infarction

We analyzed angiographic flow and myocardial salvage in 180 patients who underwent primary percutaneous transluminal coronary angioplasty (PTCA) without antecedent thrombolytic therapy for acute myocardial infarction. Thrombolysis in Myocardial Infarction (TIMI) flow grade was analyzed visually before and after PTCA. All patients underwent paired baseline (before angioplasty) and predischarge quantitative tomographic perfusion imaging with technetium-99m (Tc-99m) sestamibi techniques for assessment of the initial area at risk and final infarct size. The myocardial salvage index was defined as the proportion of jeopardized myocardium that was salvaged. After primary PTCA, TIMI grade 3 flow was obtained in 163 patients (91%), TIMI grade 2 flow in 13 patients (7%), and TIMI grade 0 or 1 flow in 4 patients (2%). There was a significant association between TIMI flow and both infarct size and salvage index. Infarct size was significantly smaller in patients with TIMI grade 3 flow than in those with TIMI grade 2 flow (15 +/- 16% vs 29 +/- 21% of left ventricular moss, p = 0.007). The salvage index was 55 +/- 41% of the area at risk in the TIMI 3 group and 27 +/- 38% of the area at risk in the TIMI 2 group (p = 0.04). After primary PTCA, restoration of TIMI grade 3 flow was necessary for optimal myocardial salvage. TIMI grade 2 flow was associated with a larger final infarct size and a lower salvage index.