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Commentary
The Angiojet Rheolytic Thrombectomy System: Does the End Justify the Means?
January 2005
Percutaneous treatment of patients with a visible intracoronary thrombus has been recognized as a procedure associated with higher risk for complications. For patients with intracoronary thrombus in the stent era, the potentially worse outcome associated with stent placement as compared to balloon angioplasty elevated the significance of how best to approach this important scenario. Focus has centered on the interventionalist’s ability to establish normal antegrade flow in the coronary artery and to minimize how the presence of thrombus interferes with this process (aptly termed slow or no-reflow).
Though few have been rigorously tested, multiple approaches have been developed to assist in the process of decreasing thrombus burden through pharmacologic and/or mechanical means. The AngioJet rheolytic system is a catheter-based system that utilizes a high-velocity saline jet, creating a vacuum at the catheter tip to remove thrombus from an artery. Thus far, the system has been used successfully in treating patients with acute myocardial infarction in small patient series. However, the downsides to using this system include set-up time, increased procedural time (including more catheter exchanges), and the placement of a transvenous pacemaker. The activated system causes transient bradycardia and heart block in about 25% of the cases.
The current article by M.S. Lee and colleagues discusses the use of intravenous aminophylline to prevent the AngioJet-related bradyarrythmias and, thus, avoid the placement of a transvenous pacemaker, a finding previously reported in abstract form by other investigators. The authors showed that 250 mg of aminophylline given intravenously before utilization of the AngioJet system did not decrease the incidence of bradyarrhythmias. Furthermore, based on this data, the authors highly recommended the placement of a temporary pacemaker prior to the performance of AngioJet thrombectomy.
Although this study was non-randomized and represents observations from a small group of patients, it remains as the only published manuscript defining the ability of aminophylline use instead of temporary pacemakers in conjunction with the Angiojet. In a recent review, Lee et al described their personal experience with 11 patients pre-treated with aminophylline and 8 patients subsequently required temporary pacing during AngioJet therapy, supporting the current article’s findings.
The need for placement of a venous sheath and temporary pacemaker does not make using the AngioJet system too arduous to use in daily practice, as long as the benefits of its use justify the risks. The justification for this usage in patients with acute infarctions may, however, be lacking given the recent presentation of the data from the AiMI trial at the TCT 2004. The AiMI trial randomized patients with acute myocardial infraction to AngioJet thrombectomy followed by definitive percutaneous treatment or definitive treatment without thrombectomy. While we await final publication of the study, the abstract presentation did show that mortality rates were higher in the thrombectomy group (4.6% versus 0.8%; p
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