Thrombus removal by aspiration is one of the adjunctive techniques used to avoid embolization during PCI for acute myocardial infarction. Numerous devices are now available, but little is known about the mechanical rationale used in comparing them. The aim of the present study was to determine parameters to obtain optimal thrombus aspiration (TA). Heparin- and antiplatelet-free blood samples were aspirated into 3 mm diameter standardized glass tubes to create a 30 mm long thrombus. Thrombus formation took place at room temperature over a period of 6 or 12 hr. Various catheters were tested using a variable vacuum device: three with right-angle distal tip (0.038'', 0.067'', and 0.070'') and one with a beveled distal (length of the beveled, 0.054''; inner diameter catheter, 0.040''). The single endpoint was complete thrombus aspiration. A total of 103 TAs were presented for the four catheters. For 6- or 12-hr-old thrombus for a given catheter, there was no significant difference in vacuum pressure required to succeed TA (P = 0.47). For 6- or 12-hr-old thrombus, the larger the contact area is, the lower the pressure needed to aspirate the thrombus. Moreover, a beveled distal tip length (0.054'') does not make it possible to succeed TA at a lower pressure. The main factor for successful TA for thrombi > or = 6 hr is inner diameter and not immediate thrombus contact area.
2006 Wiley-Liss, Inc.