Catheter aspiration in ST-elevation myocardial infarction and different extent of coronary thrombus.

Manual catheter aspiration appears to be a useful adjunct to primary percutaneous coronary intervention (PCI) in ST-elevation myocardial infarction. We investigated effects of catheter aspiration during primary PCI in patients with different extents of coronary thrombus. The study included 46 patients with no or possible thrombus (thrombus scale [TS] grades 0 to 1) and 135 patients with angiographic evidence of obvious thrombus (TS grades 2 to 5). Reference vessel diameter, which was significantly larger in the group with TS grades 2 to 5 (3.4 vs 3.2 mm, p = 0.004), was the only independent predictor of angiographically visible thrombus (odds ratio 3.3, 95% confidence interval 1.3 to 8.7, p = 0.015, per millimeter increase). Aspiration catheter was successfully advanced across the lesion in 89% of patients with TS grades 0 to 1 and 96% of those with TS grades 2 to 5 (p = 0.115). Number of aspirations varied from 1 to 5 and was significantly larger in patients with TS grades 2 to 5. Visually observable aspirate was obtained in 90% of patients with TS grades 2 to 5 and in 67% of patients with TS grades 0 to 1 (p <0.001) with more patients with TS grades 2 to 5 having aspirate >5 mm in length (49% vs 11%, p <0.001). Final Thrombolysis In Myocardial Infarction grade 3 flow (89% vs 92%), residual TS (0.2 vs 0.1), frequency of distal embolization (2% vs 6%), and early complete ST resolution (65% vs 70%) were comparable between groups with TS grades 0 to 1 and 2 to 5. In conclusion, although the amount of aspirate is larger in patients with angiographically obvious thrombus, visually observable aspirate can be obtained in most patients without definite signs of thrombus. Extent of coronary thrombus does not influence primary PCI result if manual aspiration is used.