Cath Lab Digest

Introduction
Carotid artery angioplasty and stenting (CAS) has gained acceptance in the past decade as an alternative strategy for management of carotid artery stenosis. The recent SAPPHIRE trial¹ has shown that, in high surgical risk patients, CAS is at least as good if not superior to carotid endarterectomy. The initial concern over high thromboembolic complications has been addressed by the introduction of distal embolic protection devices (EPD). Early experience with EPD indicates that they reduce microemboli-related strokes during CAS.² However, deployment of the device increases the risk of complications and the complexity of the CAS procedure. We present a case of CAS complicated by filter detachment and localized dissection, treated with mechanical filter retrieval and restenting.

Clinical Case
An 83-year-old gentleman was referred to our center for management of symptomatic carotid artery stenosis manifested by transient ischemic attacks (TIA). He reported intermittent episodes of right lower extremity weakness lasting 10–15 minutes. He had a history of hypertension, deep vein thrombosis (for which he was on chronic warfarin therapy) and advanced chronic obstructive pulmonary disease (COPD), requiring chronic oxygen supplement and limiting his functional ability to walking 25 feet before developing dyspnea. His exam was notable for left-sided carotid bruits, but revealed no focal neurologic deficits.

His diagnostic evaluation included a head CT scan which was unremarkable. Electrocardiogram showed normal sinus rhythm and left axis deviation. Echocardiogram demonstrated normal left ventricular systolic function and normal valvular morphology and physiology. Carotid duplex ultrasound exam showed 70–80% stenosis of the left internal carotid artery (ICA) and 30–40% stenosis of the right external carotid artery. CT angiography confirmed the presence of high-grade stenosis of the left ICA.

Due to the patient’s age and advanced COPD, he was considered to be at high risk for carotid endarterectomy (CEA), and therefore it was decided to proceed with percutaneous carotid intervention. A 5 Fr Vitek catheter (Cook Inc., Bloomington, Indiana) was used to engage selectively in the carotid arteries. Carotid angiogram confirmed high-grade stenosis of the left ICA (Figures 1 and 2). The lesion was in a tortuous segment of the ICA with a 90-degree angulation. The ICA/CCA angle appeared to be moderate (about 45 degrees). The Vitek catheter was exchanged over a TAD II wire (Mallinckrodt, St. Louis, Missouri) for 7 Fr Flexor shuttle sheath (Cook Inc.). An Accunet Embolic Protection filter wire (Guidant Corp. Santa Clara, California) was placed distally in the ICA without difficulty, and the left internal carotid lesion was pre-dilated with a Quantum 4.0 x 15 mm balloon (Boston Scientific, Maple Grove, Minnesota). The balloon was exchanged for an Acculink Rx 8-6 x 30 mm self-expanding stent (Guidant Corp.). Since the lesion was mainly in the internal carotid artery, the stent was specifically placed just in the internal carotid rather than extending it into the common carotid artery (CCA). The stent was further dilated with a 5.0 x 15 mm balloon. When removal of the filter was attempted, the retrieval sheath became snagged on the stent struts and could not be passed past the proximal end of the stent (Figure 3). Therefore, further dilation with a 6 x 20 mm UltraSoft balloon (Boston Scientific) to create a different angulation and allow advancement of the sheath was attempted, but was unsuccessful. Despite multiple catheter manipulations and rotations, the retrieval sheath could not be advanced. At this point, it was decided to attempt to pull the filter back into the Shuttle catheter without the retrieval sheath. While pulling back, the filter became snagged on the stent and broke off, leaving a stent and filter apparatus in the common carotid artery (Figure 4). Consideration was given to stenting the whole apparatus against the CCA wall, but it was felt that the apparatus might be bulky enough to prevent adequate stent opposition or cause significant flow limitation. Therefore, we decided to attempt mechanical capture and removal of the apparatus. Attempts at removal using a 2–4 Ensnare Minisnare (Medical Device Technologies, Gainesville, Florida) were unsuccessful. Next, a three-pronged grasper device (Applied Medical, Rancho Santa Margarita, California) was used to grab and pull out the stent-filter apparatus (Figure 5). Following this, a fairly pronounced dissection was noted at the site of the previous lesion (Figure 6), attributed to the stent-filter apparatus trauma to the vessel wall on pulling back. The dissection was treated with placement of an 8-6 x 40 mm stent in the ICA, extending into the CCA. Despite the difficulty encountered during removal of the initial EPD device, we opted to deploy a new filter system prior to the second stent placement because of the concern over microembolization from the dissection site. We felt confident that extending the stent in the CCA would lessen the angulation and allow straight passage of the removal sheath through the stent. After stent deployment, no further balloon dilation was necessary, and the filter was easily removed with a filter removal sheath (Figure 7). Throughout the procedure, the patient’s neurologic exam continued to be normal. He had no symptoms of TIA or stroke over the next 24 hours, and was discharged the following day. At three-month follow-up he was symptom-free, with no further recurrence of his baseline TIAs.

Discussion
Since the first reported case of carotid artery angioplasty by Kerber et al. in 1980,³ the interest in percutaneous carotid intervention has risen steadily because of the perceived benefits of less invasiveness and faster convalescence as compared with carotid endarterectomy (CEA).^4,5