Thrombus aspiration plus intra-infarct-related artery administration of tirofiban improves myocardial perfusion during primary angioplasty for acute myocardial infarction.

Background: We developed a new combined strategy of thrombus aspiration plus intra-infarct-related artery (IRA) bolus administration of tirofiban via the aspiration catheter in patients with ST-segment elevation myocardial infarction (STEMI). This strategy can reduce the distal embolism and achieve highly localized concentrations of tirofiban, which can improve myocardial reperfusion without increasing the risk of bleeding. The aim of this study was to investigate whether this combined strategy is superior to thrombus aspiration alone in improving myocardial perfusion in patients with STEMI undergoing primary angioplasty.

Methods: This single center study included 108 matched control patients with STEMI, angioplasty after thrombus aspiration, and 108 study patients with STEMI plus intra-IRA administration of 500 microg of tirofiban. Both groups had subsequent 12-hour intravenous infusion of 0.1 microg x kg(-1) x min(-1) of tirofiban after angioplasty. The primary end points were Thrombolysis in Myocardial Infarction (TIMI) flow immediately after angioplasty, ST-segment elevation resolution (STR) (> 70%) at 90 minutes after angioplasty, and the peak of creatine kinase-MB (CK-MB) and troponin I (TnI). The secondary end points were the left ventricular ejection fraction (LVEF) in the hospital and at nine months follow-up, cardiac death, target vessel revascularization (TVR), re-infarction and the combination of these three as major adverse cardiac events (MACE) within nine months and any bleeding events.

Results: Baseline characteristics of the two groups were well-balanced. The TIMI 3 flow showed a better tendency in the intra-IRA group than in the aspiration alone group (97.22% vs. 87.04%, chi(2) = 7.863, P = 0.049). The peak of CK-MB (83.9 (68.9 - 310.5) U/L vs. 126.1 (74.7 - 356.7) U/L, P = 0.034) and TnI (42.7 (14.7 - 113.9) ng/ml vs. 72.5 (59.8 - 135.3) ng/ml, P = 0.029) were lower in the intra-IRA group than in the aspiration alone group. LVEF in the hospital favored the intra-IRA group, (45.7 +/- 8.3)% to (42.9 +/- 12.1)%, t = 1.98, P = 0.049. There was a tendency towards a lower MACE at 9-month follow-up in the intra-IRA group although it did not reach statistical difference (Log-rank chi(2) = 2.865, P = 0.09). There was no statistical difference in any bleeding events between the two groups.

Conclusions: Thrombus aspiration plus intra-IRA bolus administration of tirofiban combined with angioplasty may be related with improved myocardium perfusion, saved more myocardium, and resulted in a better clinical prognosis.