Manual Aspiration of Iatrogenic Embolization Through a Left Internal Mammary Artery Graft

J INVASIVE CARDIOL 2010;22:E115–E118

Key words: catheter aspiration, catheter thrombosis    Although catheter thrombosis with fondaparinux¹ and macroscopic thrombus formation with enoxaparin² have been reported during coronary intervention, embolization during diagnostic catheterization is rare. However, when it occurs during diagnostic catheterization, angiographers must recognize and treat it immediately. Mechanical removal of the embolized material may effectively restore flow and salvage myocardium. Many strategies have been employed to remove thrombi or emboli^3–7 including deep cannulation with catheters, aspiration with microcatheters and aspiration with catheters designed specifically for intra-arterial aspiration.^8–15 We report two cases of iatrogenic embolization into an internal mammary artery graft leading to left anterior descending artery occlusion and imminent acute anterior infarction successfully treated with manual aspiration thrombectomy.    Case 1. A 58-year-old female with bypass surgery ten years earlier presented with increasing episodes of chest discomfort and occasional rest discomfort. Because of iliac tortuosity documented during prior catheterization, a 6 French (Fr) 45 cm Pinnacle sheath (Terumo, Somerset, New Jersey) was passed into the right femoral artery. Coronary and vein graft arteriography demonstrated a 100% mid-left anterior descending (LAD) lesion, 100% circumflex occlusion with the distal circumflex obtuse marginal filling by a patent saphenous vein graft and a 100% right coronary artery occlusion with the distal right coronary artery filling via a patent vein graft. The left subclavian was accessed with the Judkins right catheter, and a 0.035 inch J-tipped wire was passed distally into the vessel. Over this, the catheter was changed for a 5 Fr internal mammary artery catheter and engaged with relative ease. Injection of the left internal mammary artery (LIMA) demonstrated that the distal LAD was 100% occluded with an abrupt cutoff (Figure 1) typical of distal embolization.    The patient immediately developed chest pain with ST elevation in the anterior leads on a 12-lead electrocardiogram (ECG). Anticoagulation with bivalirudin was initiated and a 6 Fr LIMA guide catheter with side holes was placed. A Prowater wire (Abbott Vascular Devices, Redwood City, California) was advanced through the serpentine LIMA vessel into the native LAD beyond the occlusion. However, neither a Pronto catheter (Vascular Solutions, Inc., Minneapolis, Minnesota) nor an Export catheter (Medtronic, Inc., Minneapolis, Minnesota) could be passed over this wire to the point of occlusion. An Asahi Grand Slam wire (Abbott Vascular) was passed alongside the Prowater wire past the lesion, and the Prowater wire was removed so as to allow for placement of the aspiration catheter in the 6 Fr guide. The Export catheter (Medtronic) was delivered over the Grand Slam wire and several runs were performed beyond the occlusion point with immediate chest-pain relief and ST-elevation resolution. Angiography revealed minimal disease in the distal LAD and no significant dissection at any location in the LIMA (Figure 2). Thrombolysis in myocardial infarction (TIMI) 3 flow was restored, ECG showed normalization of the ST-segment elevation and the patient’s chest pain promptly resolved. Her serial cardiac enzymes were normal and she was discharged the next day.    The aspirate included a dark red vermiculoform body measuring 9 mm by 1 mm. (Figure 3). Histologic analysis demonstrated fibrin thrombus (Figure 4).    Case 2. A 79-year-old male was referred for elective cardiac catheterization after screening stress echocardiography demonstrated anterior and inferior ischemia. Seven years earlier he had a myocardial infarction followed by bypass surgery.    Coronary and vein graft arteriography via the right femoral artery using 4 Fr catheters demonstrated a 100% LAD occlusion and 100% circumflex occlusion with a patent vein graft filling the distal circumflex. The 4 Fr Judkins right-4 catheter passed into the left subclavian artery. Through it, a .035 inch J-tipped exchange wire was passed into the distal subclavian artery, and the catheter was exchanged for a 4 Fr Behar Internal Mammary VB-1 catheter (Cordis Corp., Miami Lakes, Florida). Blood was aspirated and the catheter was pulled proximally until it seated in the internal mammary artery. There was mild pressure-damping, and a very gentle test injection showed unobstructed flow down the graft and into the LAD (Figure 5). A brisk injection with cine imaging demonstrated a new cutoff half way down the LAD distal to the graft anastomosis (Figure 6).    The patient immediately developed chest discomfort. Heparin was administered and titrated to an activated clotting time of 220 seconds. A 0.014 Ironman wire was passed through the diagnostic catheter. The diagnostic catheter and the sheath were exchanged over this for a 6 Fr sheath and 6 Fr internal mammary artery catheter. A 0.014 Asahi soft wire (Abbott Vascular) was passed parallel to the Ironman wire into the distal LAD, and the Ironman wire was removed. An Export aspiration thrombectomy catheter (Medtronic) was passed to the lesion and blood was aspirated. The aspirate did not include any thrombus. Repeat imaging showed that the cutoff had migrated several centimeters distally. The Export catheter was passed down to the distal LAD, and this time, negative pressure was maintained to produce suction at the catheter tip as the catheter was removed. Upon removal, an 8 x 2 mm red-tan mass was attached to the end of the catheter. Arteriography demonstrated a widely patent vessel with normal flow and no residual stenosis (Figure 7). The patient’s symptoms immediately resolved. Subsequently, the proximal LAD (via the native left main coronary artery) was stented to provide perfusion to a large first diagonal branch. Serial creatine kinase-MB enzymes remained within normal limits. An ECG after the procedure was unchanged from baseline. At follow up 1 year later, the patient was free of angina. Histologic examination demonstrated fibrin thromboemboli (Figure 8).    Discussion. These two cases demonstrate several important points. First, iatrogenic embolization during routine diagnostic catheterization is rare,¹⁶ and had not been observed by the operators (JCB and TS) over several thousand cases. Catheterization of in situ internal mammary arterial grafts involves several aspects specific to the artery that may predispose patients to thrombo-embolus formation. Patients with prior bypass surgery are older compared to typical catheterization patients, have more severe aortic atherosclerosis and are more likely to have serpentine aorto-iliac arteries that make catheter passage more difficult and may require use of long sheaths, as in patient 1. Passage of a wire through the subclavian artery may be difficult, catheter exchanges over long wires are commonly required and selective cannulation of the internal mammary artery may require several wire-facilitated trips up the subclavian artery. To prevent complications, it is important to minimize wire time in the body and carefully aspirate catheters after the wire is removed. However, in both patients reported here, these precautions were followed but did not prevent embolization of fibrin thrombus, presumably from the wire. While there are no data to support the practice, both operators now use low-dose heparin before left internal mammary artery (LIMA) catheterization.    A second point is that when thromboembolization occurs, it must be recognized rapidly and treated effectively. In our patients, the diagnosis was clear from the typical appearance of the arterial occlusion, accompanied by the sudden onset of chest pain typical of ischemia. In both cases, immediate aspiration with a manual thrombectomy catheter was effective. Notably, in one case, the embolus was too large or too organized to be aspirated through the catheter and was removed only by applying suction to keep it trapped against the aspiration lumen in the catheter as the catheter was removed.    Finally, these cases demonstrate the potential advantage of performing catheterization in angioplasty-capable catheterization laboratories. From the Department of Cardiology, Geisinger Medical Center, Danville, Pennsylvania. The authors report no financial relationships or conflicts of interest regarding the content herein. Manuscript submitted December 19, 2008, provisional acceptance given January 16, 2009, revision received January 10, 2010 and final version accepted April 12, 2010. Address for correspondence: Arun Kalyanasundaram, MD, MPH, Department of Cardiology, Geisinger Health System, 100 N. Academy Avenue, Danville, PA 17822. E-mail: arunksundaram@gmail.com References

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