Use of the X-SIZER‚Ñ¢ Catheter System in the Treatment of Acute Thrombotic Coronary Occlusion

Nicholas D. Palmer, MD, Sanjeev B. Patel, MD, David R. Ramsdale, MD
Nicholas D. Palmer, MD, Sanjeev B. Patel, MD, David R. Ramsdale, MD
The presence of thrombus within coronary lesions is associated with an increased incidence of abrupt vessel closure, peri-procedural myocardial infarction and death after percutaneous transluminal coronary angioplasty (PTCA). In addition to improved pharmacological therapies, such as platelet glycoprotein IIb/IIIa inhibitors, a number of mechanical approaches have been developed to deal with thrombus. Transcatheter aspiration, distal clot displacement, thrombectomy and ultrasound thrombolysis have all shown promise in reducing the clot burden and degree of distal embolization prior to PTCA and stenting. The X-SIZER™ thromboatherectomy catheter system (EndiCOR Medical, Inc.) was initially developed for the treatment of thrombus in acute coronary syndromes. We report on the use of this system in a patient presenting with an acute coronary syndrome due to occlusion of the left circumflex coronary artery. Case Report. A 64-year-old man was admitted to his local hospital with central chest pain. Prior to this, he had developed ventricular fibrillation from which he was successfully resuscitated. He had previously been fit and well with no prior history of ischemic heart disease. Cardiovascular risk factors were previous smoking and hypercholesterolemia. His initial electrocardiogram demonstrated no significant ischemic changes; however, the troponin T level after 12 hours was significantly elevated (3.39 µg/l), confirming non-Q wave myocardial infarction. He was treated with aspirin, beta-blockers and low molecular weight heparin. He had further episodes of chest pain with labile ischemic changes in the lateral chest leads. Prior to transfer to our center, he had a further cardiac arrest due to ventricular fibrillation which responded to a 200 joule DC shock. He was subsequently given an intravenous infusion of amiodarone. At cardiac catheterization, performed via the right femoral approach, left ventricular angiography demonstrated severe hypokinesia of the inferoposterior wall with an ejection fraction of 35%. The left circumflex artery was occluded proximally with no visible thrombus and no discernible antegrade flow to the distal vessel (Figure 1A). There was mild atheromatous disease in the left anterior descending and right coronary arteries. It was decided to attempt to reopen the left circumflex artery. With support from an 8 French (Fr) guide catheter, a 0.014´´ hi-torque floppy guidewire was negotiated with some difficulty across the occlusion to the distal vessel. A 1.5mm X-SIZER catheter was advanced to the occlusion and activated (Figure 1B). Initial attempts to cross the occlusion were unsuccessful, although some antegrade flow was restored (Figure 1C). A second pass of the X-SIZER catheter produced a further improvement in flow, but revealed a severe residual stenosis (Figure 1D). A small quantity of thrombotic material was extracted; histological analysis revealed predominantly platelet aggregates and fibrin but no atheroma. A 2.0 mm MAESTRO™ balloon (Sorin) was used to pre-dilate the lesion, resulting in a significantly improved lumen (Figures 1E and 1F). A 3.0 x 19 mm JoFlex™ stent (Jomed, Helsingborg, Sweden) was deployed and post-dilated to 12 atmospheres using a 3.0 x 10 mm Worldpass™ balloon (Cordis Corporation, Miami Lakes, Florida). An excellent final angiographic result was achieved with no residual stenosis and TIMI 3 flow (Figures 1G and 1H). There were no peri-procedural or in-hospital complications. Subsequent creatine kinase MB levels were normal. The patient was discharged two days later. Discussion. Thrombus within a diseased coronary artery significantly reduces the ability to restore flow during percutaneous intervention. It is associated with an increased risk of myocardial injury due to distal embolization (DE).1 Pharmacological approaches, such as platelet glycoprotein IIb/IIIa receptor inhibitors, have consistently been shown to decrease procedural complications and subsequent major cardiovascular events.2 Mechanical approaches for dealing with thrombus include simple compression with balloon angioplasty, as well as aspiration and removal using atherectomy devices. Thrombus aspiration prior to adjunctive PTCA and stenting results in significant improvement in Thrombolysis In Myocardial Infarction (TIMI) flow with successful removal of intracoronary thrombus.3 In conjunction with intravenous antiplatelet therapy, this technique appears to reduce the risk of DE.4 Transluminal extraction atherectomy (TEC) has shown comparable procedural success rates to PTCA although DE is still a significant problem, occurring in 8.3% of treated patients, with significantly increased in-hospital mortality and morbidity.5,6 The X-SIZER thromboatherectomy catheter is a novel device which, in addition to thrombus removal, has demonstrated potential for the removal of occlusive tissue in degenerated saphenous vein bypass grafts, in-stent restenosis and chronic coronary occlusions. It comprises a helical cutter rotated at 2,100 rpm within the catheter tip and vacuum removal of tissue debris. The hand-held control module enables easy use. Initial in vitro studies demonstrated a relatively low incidence of DE compared to the other conventional techniques. A pilot study of 50 patients with saphenous vein bypass graft disease and native coronary lesions with associated thrombus demonstrated a high procedural success rate, effective reduction of the thrombus burden with significant improvements in TIMI flow and a lower 30-day major adverse cardiac event rate compared to other thromboatherectomy and aspiration devices (6.0% versus 15.1%; p
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