Endovascular Treatment of Carotid Artery Aneurysms with Stent Grafts
- Volume 14 - Issue 5 - May, 2002
- Posted on: 8/1/08
- 1 Comments
- 50936 reads
Aneurysms of the carotid arteries is a rare but well described entity. Cervical carotid artery aneurysms can cause cerebral embolism and transient ischemic attacks.1 Surgery, however, is often difficult because of the location and the damaged arterial wall and may result in sacrifice of the internal carotid artery. We present two cases of carotid aneurysms successfully treated with stent grafts.
Case Report #1: A right-handed, 65-year-old male presented with right carotid territory transient ischemic attacks in the form of recurrent amaurosis fugax and left arm weakness. Duplex ultrasound revealed heterogenous plaque in the right internal carotid artery with 20–39% luminal stenosis and a dilated aneurysmal area in the right internal carotid artery. The left internal carotid artery had 40–59% stenosis with heterogenous plaque in the proximal portion of the vessel. Carotid angiography was performed, which revealed an 11 mm aneurysm of the distal right carotid artery immediately below the petrous portion. Informed consent was obtained after a comprehensive discussion of risks and benefits. The patient was not deemed a surgical candidate because the lesion was high and surgical access would have been difficult. The patient was brought to the vascular interventional laboratory, sedated with short-acting intravenous sedation, and a 6 French (Fr) arterial sheath inserted in the femoral artery. The patient received 6,000 units of heparin to achieve an ACT of 299. Subsequently, a 9 French, 70 cm long sheath system (Cook Corporation, Bloomington, Indiana) was placed into the descending part of the aorta. Through this, a 5 French, 125 cm JR4 catheter (Cordis Corporation, Miami Lakes, Florida) was advanced. The origin of the common carotid artery was carefully intubated with the JR4 catheter and a 0.035´´ Storq guidewire (Cordis Corporation) was placed selectively in the right common carotid artery. The 9 Fr sheath was advanced over the 5 Fr JR4 catheter, and the tip of the sheath was then selectively placed in the distal right common carotid artery. Selective angiograms were performed which confirmed the previously known aneurysm of the right internal carotid artery (Figure 1). The right internal carotid artery proximal to the aneurysm was measured by quantitative angiography and measured 5.73 mm in diameter. Subsequently, the Storq guidewire was placed in the distal internal carotid artery, a 6.0 x 20 mm Wallgraft Endoprosthesis (Boston Scientific/Scimed, Maple Grove, Minnesota), advanced across the aneurysm and deployed. The stent was post dilated with a 4.0 x 20 mm Opta LP balloon (Cordis Corporation) at 12 atmospheres for 40 seconds, but there was still a 20% residual stenosis in its proximal portion. Subsequently, the stent was post dilated with a 5.0 x 20 mm Opta LP balloon catheter, without any significant residual stenosis. Following this, angiograms showed no residual stenosis, good inflow into the right internal carotid artery system, and complete obliteration of the aneurysm (Figure 1). The patient received 325 milligrams of aspirin and 300 milligrams of clopidogrel prior to the procedure and was discharged home the following day on clopidogrel (75 mg PO QD) for 4 weeks and on aspirin (325 mg PO QD). Post-procedure, the patient did not have any further episodes of transient ischemic attacks or other symptoms at 8-month follow up. Duplex ultrasonography at 8-months revealed widely patent stent graft in the right internal carotid artery and complete obliteration of the aneurysm.
Case Report #2: A 64-year-old male with pulsatile neck swelling and persistent neck discomfort was referred for evaluation. His past medical history was significant for neck cancer in 1985, which was treated with surgery and radiation. He developed symptomatic right internal and common carotid artery stenosis in 1998 and underwent carotid stenting, as he was not deemed a surgical candidate because of prior neck surgery and radiation. A duplex ultrasound evaluation of the pulsatile mass revealed aneurysmal dilatation of the right carotid artery with 40% luminal stenosis. The left internal carotid artery had 20–39% luminal stenosis. Carotid angiography revealed an aneurysm involving the distal right common carotid artery and proximal internal carotid artery (Figure 2). Informed consent was obtained after a comprehensive discussion of risks and benefits. A short 11 French sheath system was placed in the left femoral artery and subsequently, a 75 cm long, 9 Fr sheath (Cook Corporation) was advanced into the thoracic descending aorta. The patient received 7,000 units of heparin and achieved an ACT of 287 for this procedure. A 5 Fr, 125 cm JR4 catheter (Cordis Corporation) was then advanced through the 9 Fr sheath. The origin of the right common carotid artery was carefully intubated with the JR4 catheter and a 0.035´´ Magic Torque guidewire (Boston Scientific/Scimed) and the tip of the JR4 placed selectively in the right common carotid artery. The 9 Fr sheath was advanced over the 5 Fr JR4 catheter and the tip of the sheath was then selectively placed in the distal right common carotid artery. Selective angiograms were performed which confirmed the previously known aneurysm involving the distal right common carotid artery and the proximal right internal carotid artery. The aneurysm measured 12.7 mm at its widest. The Magic Torque guidewire was placed in the distal part of the right internal carotid artery. Following this, a 6.0 x 20 mm Wallgraft (Boston Scientific/Scimed) was advanced across the distal part of the aneurysm and deployed. The Wallgraft, however, did not completely cover the aneurysm and there was still filling of the proximal part of the aneurysm. At this time, a 2.0 x 30 mm OpenSail balloon (Guidant Corporation) was placed selectively in the right external carotid artery and the artery was embolized selectively with two, 5.0 Vortex coils and a 4.0 Vortex coil (Boston Scientific, Target Therapeutics, Fremont, California). The right external carotid artery was embolized to prevent retrograde filling of the aneurysm. After successful coil embolization and occlusion of the right external carotid artery, an 8.0 x 20 mm Wallgraft was placed to cover the proximal part of the aneurysm with some overlap of the previously implanted Wallgraft. Following deployment of the two stent grafts the aneurysm was completely obliterated (Figure 2). The patient received 325 milligrams of aspirin and 300 milligrams of clopidogrel prior to the procedure and was discharged home the following day on clopidogrel (75 mg PO QD) for 6 weeks and on aspirin (325 mg PO QD). Post-procedure, the patient had alleviation of his neck discomfort and patient remains asymptomatic at 9-month follow-up. Duplex ultrasonography at 9-month revealed patent stent graft in the right internal carotid artery and no evidence of an aneurysm.
Discussion. Aneurysms of the carotid arteries may cause cerebral embolism or flow-related complications.2,3 The location of the aneurysm often makes surgical correction difficult and leads to perioperative lower cranial nerve injuries and neurological deficits.4–6 Because adequate distal exposure and direct surgical repair of these lesions are often not possible, conventional treatment has been deliberate arterial occlusion.7 Endovascular intervention with bare stents has previously been reported as an alternative to surgery with reasonable results.8–13 Uncovered stents are effective in treating dissecting aneurysm with intimal flap or small defects in the arterial wall as the stent mesh impedes flow into the aneurysmal sac, inducing thrombosis, or relocating the intimal flap to occlude the aneurysm.14 However, flow into wide-necked aneurysms is difficult to exclude with an uncovered stent, so coil embolization of the sac through the stent is often required.14 Wide-necked saccular aneurysms or pseudoaneurysms can be more appropriately treated with a covered stent, leading to immediate and definitive reconstruction of the arterial wall.15 Vein-covered stents have also been successfully employed in treating carotid pseudoaneurysms.16–18 Initial animal experiments have demonstrated the safety and feasibility of covered stents for carotid aneurysms,19,20 and this has been followed by clinical case reports.14,15,21
The natural history of untreated carotid artery pseudoaneurysm is not well known. The most serious complication is life-threatening hemorrhage and urgent arterial occlusion of the feeding artery is presently the treatment of choice.16 Most patients undergo prophylactic surgical or endovascular treatment because of the catastrophic consequence of hemorrhage and rupture. The first case reported by us had recurrent TIA’s in spite of antiplatelet therapy and the second individual had persistent neck discomfort, which was affecting his quality of life. We demonstrate the use of stent grafts to treat these two patients to completely obliterate the aneurysmal sac. Since the external carotid artery came off the aneurysmal area in the second patient, it was embolized with coils. Advantage of using a stent graft over a bare stent is complete exclusion and eventual thrombosis of the aneurysmal sac. Covered stents have been used in the subclavian and common carotid location for pseudeoaneuryms related to trauma with excellent long-term results.22,23 A bare stent would not completely eliminate the risk of embolization since the aneurysm would still communicate with the true lumen through the stent struts. Potential limitations of a covered stent include larger delivery systems compared to bare stents and need for technical expertise for appropriate delivery. Another potential limitation may be the increased thrombogenicity related to the covering on the stent. Individuals with severe aorto-iliac tortuosity, severe peripheral vascular disease precluding placement of a 9 French sheath, and coagulopathy would not be ideal candidates for stent grafts.
In conclusion, the two cases described here suggests that endovascular stent graft placement is a safe, feasible and effective way to treat carotid artery aneurysms. Intermediate term follow-up results at 8-9 months revealed continued patency of the carotid arteries and obliteration of the aneurysms.