Usefulness of the rescue PT catheter to remove fresh thrombus from coronary arteries and bypass grafts in acute myocardial infarction

Abstract

I the setting of an acute myocardial infarction (AMI), thrombolytic therapy has proved to reduce mortality and improve left ventricular function.1–3 A good or even better alternative is primary angioplasty.4–6 Several devices have been developed to remove thrombus material. The disadvantages of most of these devices are that they are complicated, and difficult to handle in the acute setting for interventionalists who are not experienced with these devices. We describe the clinical experience with a simple thrombectomy system using a catheter that can be handled like a balloon. This study evaluates the safety and efficacy of the Rescue percutaneous thrombectomy (PT) system (Boston Scientific, Maple Grove, Minnesota) in the setting of AMI or unstable angina pectoris. • • • The thrombectomy system consists of a very flexible, 4.5Fr polyethylene catheter that can be advanced over a standard 0.014-in guidewire through a 7Fr guiding catheter using a monorail system. The catheter has an oblique tip to facilitate passage through the lesion and a marker to improve visibility during fluoroscopy (Figure 1). The proximal end has an extension tube connected to a vacuum pump (0.8 bar) with a collection bottle. The removed thrombus material is collected on a filter in the collection bottle. While the catheter is advanced and pulled back through the thrombus, continuous suction is applied. When necessary, several runs can be performed. In case of distal embolization, the catheter can be advanced distally over the guidewire to remove the embolized material. Thrombectomy using the Rescue PT system was considered when a coronary angiogram recorded in the setting of an AMI raised the suspicion of a considerable amount of thrombus in a venous coronary artery bypass graft or native coronary artery. At the beginning of the procedure 10,000 IU of heparin was administered to the patients not pretreated with a thrombolytic agent. A coronary angiogram was performed before and after guidewire placement, after every passage of the Rescue PT catheter, and when applicable after additional coronary intervention. Coronary flow was classified according to the Thrombolysis In Myocardial Infarction (TIMI) trial.7 Angiographic analysis was performed to evaluate presence and removal of the thrombus and distal embolization. The removal of thrombus was also determined by the material on the filter in the collection bottle. The use of additional medication and coronary intervention, including stent placement, were at the discretion of the operator. Fifty-one lesions were treated in 50 patients (8 women and 42 men). One patient had a thrombus in the left anterior descending (LAD) artery and first diagonal branch because of distal embolization of thrombus from the proximal LAD artery after treatment with a thrombolytic agent. In 30 patients (60%) thrombectomy was performed after failed thrombolysis. In 43 patients (86%) the estimated age of the thrombus was ,6 hours, in 7 patients, thrombus age was 6 to 10 hours, and in 2 patients, it was .10 hours. In 45 patients thrombectomy was performed in a native coronary artery and in the remaining 5 patients in a venous coronary artery bypass graft (graft age range 13 to 18 years). The lesion could be reached in all vessels and thrombus material was removed from 48 of the 51 From the Department of Cardiology, University Hospital Maastricht, Maastricht; and Department of Cardiology, Catharina Ziekenhuis, Eindhoven, The Netherlands. Dr. van Ommen’s address is: Department of Cardiology, University Hospital Maastricht, PO Box 5800, 6202 Maastricht, The Netherlands. E-mail: vvo@scar.azm.nl. Manuscript received October 20, 2000; revised manuscript received and accepted February 27, 2001. FIGURE 1. Photograph of the tip of the Rescue PT system showing the oblique tip and the marker band.