Journal of Invasive Cardiology

METHODS
This is a retrospective study of the 30-day and six-month clinical outcomes in a tertiary university hospital. All patients who underwent X-Sizer facilitated primary or rescue PCI for STEMI during the period from November 2000 to February 2003 formed the study cohort. Diagnosis of STEMI was based on chest pain suggestive of coronary ischemia for more than 30 minutes and an ECG showing ST-segment elevation > 1mm in two contiguous leads or new onset left bundle branch block, with or without cardiac enzyme elevation. All patients underwent PCI within 12 hours after onset of chest pain. For patients who received thrombolytic therapy, diagnosis of failed thrombolysis was based on one or more of the following parameters at 90 minutes after administration of thrombolytic therapy: 1) unresolved chest pain; 2) persistent ST-segment elevation; or 3) hemodynamic compromise. Submission for PCI was based on the decision of the attending physicians. As per hospital protocol, patients found to have significant left main coronary stenosis by angiography were sent for emergency bypass surgery.
The PCI procedures were carried out in a standard fashion in the cardiac catheterization laboratory. Informed consent was obtained from all patients. They received a combined aspirin and ticlopidine/clopidogrel loading dose prior to the procedure. Weight-adjusted (100 U/kg) heparin with target activated clotting time (ACT) of > 300 seconds was administered before balloon inflation or stent deployment. When administration of a platelet glycoprotein IIb/IIIa inhibitor was anticipated, a reduced dose (70 U/kg) of heparin was administered with target ACT between 200 and 250 seconds. Details of the procedural strategy, including direct stenting versus balloon predilatation, use of an intra-aortic balloon pump (IABP) or other adjunctive devices, were left to the discretion of the individual operator.
The X-Sizer thrombectomy system consists of a dual-lumen catheter shaft connected to a handheld control module. The details have been described previously. The X-Sizer catheter was inserted over a 0.014-inch guidewire and was gently advanced to the culprit lesion. The inner lumen contains a helical cutter rotated at 2.100 rpm. Activation of the system leads to fragmentation of the thrombus, which is concurrently removed by vacuum through the outer lumen.