Interposition grafting of large extracranial carotid aneurysm

© 2011 by the Texas Heart ®

Institute, Houston

Volume 38, Number 1, 2011 52

Interposition Grafting

of Large Extracranial

Carotid Aneurysm

Extracranial carotid aneurysms are a rare entity and carry an inherent risk of thromboem-bolic complications. Treatment options consist of endovascular and conventional surgical techniques. We describe the cases of 3 patients who were treated with an interposition graft for a large extracranial carotid aneurysm.

The patients had presented with an extracranial carotid aneurysm with a diameter of 30 to 43 mm. In all cases, the aneurysm was excluded by means of an interposition graft, without major perioperative complications. There was 1 case of temporary paresis of the facial nerve and another of temporary paresis of the vocal cord. After a mean follow-up period of 14 months, all patients were alive, and there were no neurologic deficits.

A retrospective analysis was performed of patients who had undergone conventional surgical treatment of extracranial carotid aneurysms. The patients’ characteristics, symp-toms, surgical interventions, complications, and deaths were all documented.

Carotid aneurysms can safely be excluded by interposition grafting, and this treatment should still be considered for most patients, although endovascular repair might provide a valid alternative. (Tex Heart Inst J 2011;38(1):52-5)

E

4% of all peripheral aneurysms1,2_{; only 0.1% to 2% of all surgical carotid}

pro-cedures are performed for aneurysms.3 _{Local pain and a pulsating mass in the}

neck are the most frequently described symptoms.1,4,5 _{Patients might also present with}

ischemic stroke, transient ischemic attack, amaurosis fugax, or cranial nerve com-pression. Most patients, however, remain asymptomatic. Carotid artery aneurysms are usually diagnosed by means of ultrasonographic scanning. Additional diagnostic testing—by computed tomographic angiography, magnetic resonance imaging, or an-giography—can lead to more accurate information on the aneurysm’s size and its

rela-tionship to surrounding structures.4 _{Most aneurysms in the carotid vasculature occur}

at the level of the common carotid artery, followed by that of the internal carotid

ar-tery. Aneurysms of the external carotid artery are extremely rare.6 _{Although most}

ca-rotid artery aneurysms are caused by atherosclerosis, other common causes include trauma and infection. Less frequent causes are cystic medial necrosis, Marfan

syn-drome, Takayasu arteritis, and idiopathic medial arteriopathy.2

Indications for intervention arise chiefly from the risk of rupture and embolic

se-quelae, or from the presence of cranial nerve dysfunction.7-9 _{Treatment options consist}

of surgical exclusion with an interposition graft, ligation of the artery, and endovas-cular exclusion with a stent-graft. Between 2007 and 2008, we treated 3 carotid-aneurysm patients with interposition grafts, in 2 different hospitals. Results of this treatment are presented herein.

Case Reports

A 71-year-old man with a history of hypertension, type 2 diabetes mellitus, hyper-cholesterolemia, coronary artery disease, moderate aortic valve stenosis, and obesity presented with a thiamine deficiency attributable to alcohol abuse. Coincidentally, a carotid artery aneurysm was found. Computed tomographic angiography showed a saccular aneurysm of the left internal carotid artery with a maximal diameter of 36 mm (Fig. 1). The right carotid artery at the level of the bifurcation was modestly en-larged, at 14 mm.

Case

Series

Johannes E.M. Sybrandy, MD Jacob Buth, MD, PhD Clark J. Zeebregts, MD, PhD

Key words:

Aneurysm/sur-gery; carotid artery diseas-es; carotid artery, common/ surgery; carotid artery, in-ternal/surgery; cranial nerve injuries/etiology; graft, inter-position; stents; treatment outcome

From: Departments of

Surgery (Drs. Huyzer and Zeebregts), Division of Vas-cular Surgery, University Medical Center Groningen, 9700 RB Groningen; Sur-gery (Dr. Reijnen), Alysis Zorggroep, Location Rijn-state, Arnhem; Surgery (Dr. Sybrandy), Hospital Gelderse Vallei, Ede; and Vascular Surgery (Dr. Buth), Catharina Hospital, Eind-hoven; The Netherlands

Address for reprints:

Clark J. Zeebregts, MD, PhD, Department of Surgery, Division of Vascular Surgery, University Medical Center Groningen, Hanzeplein 1, P.O. Box 30.001, 9700 RB Groningen, The Netherlands E-mail: czeebregts@hotmail.com

Texas Heart Institute Journal Extracranial Carotid Aneurysm 53

At first, treatment of the asymptomatic aneurysm was conservative, consequent to the patient’s multi-ple comorbidities. Because of myocardial ischemia, a coronary artery stenosis was treated with angioplasty and stenting. During 8 months of follow-up, however, the carotid aneurysm expanded to 43 mm. Ultrasono-graphic scanning showed a mural thrombus within the aneurysm. Although the aneurysm remained asymp-tomatic in terms of embolic complications, we decided to exclude it by open surgery.

The procedure was performed with the patient under general anesthesia and monitored by electroencephalog-raphy (EEG) and transcranial Doppler (TCD) echo-cardiography. First, the mandible was subluxated and temporarily fixed, in order to expose the distal end of the aneurysm. Then, we dissected the internal carot-id artery and carot-identified the hypoglossal nerve. The an-eurysm was opened after clamping, mural thrombus was removed, and the aneurysm was partly resected. The greater saphenous vein was used as an interposi-tion graft. During the entire procedure, the EEG re-mained normal and no temporary shunt had to be used. Postoperatively, the patient was placed on a lifelong reg-imen of aspirin, taken daily. There were no postopera-tive complications, and on the 3rd day after surgery the patient was discharged from the hospital in good am-bulatory condition. After a follow-up of 2 years and 4 months, the bypass was patent and there were no neu-rologic complications.

Patient 2

An 85-year-old man, a nonsmoker with an extensive cardiac history who had survived a ruptured abdominal aortic aneurysm 5 years earlier, presented with collapse,

without focal neurologic deficits. Physical examination revealed a pulsatile mass on the left side of the neck with a palpable thrill and systolic bruit. Duplex ultrasono-graphic scanning and computed tomoultrasono-graphic angiog-raphy (Fig. 2) confirmed the diagnosis of a saccular aneurysm of the common carotid artery (diameter, 38 mm), with signs of a penetrating atherosclerotic ulcer. The right carotid artery was normal.

It was decided to perform an emergency surgical re-pair, because of the neurologic symptoms the night before. The procedure was performed with the pa-tient under general anesthesia, without EEG or TCD monitoring. The aneurysm was exposed and opened after clamping. Cerebral flow was secured by using a temporary shunt throughout the operation. A rup-tured atherosclerotic ulcer was found. The aneurysm was excluded by means of an 8-mm ePTFE interposi-tion graft. Postoperatively, the patient resumed taking acenocoumarol, on a daily lifelong regimen. His postop-erative course was complicated by a temporary bruising of the left vocal cord, which resolved within months. There were no neurologic sequelae. The patient was

dis-Fig. 1 Patient 1. Computed tomographic angiogram shows a

left-sided saccular aneurysm of the internal carotid artery (ar-rows) in the axial plane.

Fig. 2 Patient 2. Computed tomographic angiogram shows a

saccular aneurysm of the common carotid artery (arrows) in the coronal plane.

Volume 38, Number 1, 2011 54

charged from the hospital on the 4th postoperative day. At the 8-month follow-up appointment, the interposi-tion graft was patent and there were no neurologic se-quelae.

Patient 3

A 70-year-old woman, a nonsmoker, was being analyzed for thoracic pain caused by a Stanford type B dissec-tion. She had a history of hypertension, hypercholester-olemia, and treatment for aneurysms of the abdominal aorta and left common iliac artery. During her physical examination, an aneurysm of the left internal carotid artery was found. Duplex ultrasonography and magnet-ic resonance imaging showed a saccular aneurysm of the left internal carotid artery with a diameter of 30 mm (Fig. 3). The right internal carotid artery was slightly enlarged, to a maximum diameter of 15 mm.

The patient underwent operation within 1 week, under EEG monitoring. A temporary shunt was used during the procedure. The aneurysm was exposed and

the facial, accessory, and hypoglossal nerves were all identified. There was no mural thrombus. The aneu-rysm was excluded by means of a greater saphenous vein interposition graft. Postoperatively, the patient contin-ued taking aspirin. As a sequela of the operation, there was a temporary paresis of the facial nerve that resolved within 3 months. She was discharged from the hospital on the 4th postoperative day.

Two months afterwards, a stent-graft was implanted in the descending aorta for a post-dissection false aneu-rysm. Because there was a clinical suspicion of connec-tive-tissue disease, due to the patient’s unusually long fingers and toes, genetic analysis was performed. Nei-ther Marfan syndrome nor Ehlers-Danlos syndrome type 4 could be proved. After a follow-up period of 18 months, the interposition graft was patent and there were no neurologic sequelae.

Discussion

In the present article, we have shown that carotid ar-tery aneurysms can be safely excluded with interposi-tion grafts. In our 3 patients, there were no perioperative strokes or other major neurologic complications. How-ever, an instance of temporary paresis of the facial nerve and an instance of temporary paresis of the vocal cord occurred, in 2 different patients. These results are in

accord with observations in earlier reports3,10 _of

surgi-cal exclusion of carotid artery aneurysms. In a series of 67 surgically treated carotid aneurysms, El-Sabrout

and Cooley3 _{reported a rate of 9% for death or major}

stroke and a rate of 6% for cranial nerve injury. Dur-ing a follow-up period of approximately 6 years, 28% of the patients died, due mainly to cardiac causes. In 2009,

Attigah and colleagues10 _{published their long-term}

re-sults of surgical therapy of extracranial carotid artery aneurysms in 57 patients. The perioperative stroke rate was 2%, and 6% experienced a transient ischemic at-tack. Permanent and transient cranial nerve injury oc-curred in 6% and 20% of all patients, respectively. After follow-up periods of 5, 10, 15, and 20 years, the actuar-ial survival rates were 90%, 77%, 65%, and 57%; and the ipsilateral stroke-free rates were 96%, 96%, 93%, and 87%, respectively.

Endovascular repair of carotid aneurysms has been described as a quick and less invasive alternative that

causes fewer nerve injuries.8,9 _{Endovascular repair can}

especially benefit high-risk patients: that is, those with severe comorbidity or with a “hostile neck” unsuitable for surgery. However, the main concern associated with endovascular procedures in the carotid artery—the risk of embolic complications—remains. Because there are few reports on endovascular treatment of carotid aneu-rysms, the actual risk of stroke is still unknown. There have been 2 case reports of successful endovascular ex-clusion in patients with hostile necks after radiation

Fig. 3 Patient 3. Magnetic resonance image shows a saccular

Texas Heart Institute Journal Extracranial Carotid Aneurysm 55

treatment.9,11 _{These cases have short follow-up periods}

but certainly suggest that endovascular treatment is a useful alternative in cases that are unsuitable for surgery. There are also several reports of successful

endovascu-lar exclusion of traumatic carotid pseudoaneurysms.12,13

Patel and colleagues13 _{have stated that most patients}

with saccular aneurysms might be candidates for endo-vascular treatment. In a multicenter study, Radak and

co-investigators7 _{found that 51% of all carotid}

aneu-rysms are saccular. Zhou and associates8 _{retrospectively}

compared 2 cohorts of patients with carotid aneurysm. Patients in the first group had undergone operative re-pair in the first 10-year period, and patients in the sec-ond group had undergone either surgical correction (30%) or endovascular exclusion (70%) in the second 10-year period. Zhou concluded that treatment of ex-tracranial carotid artery aneurysms had largely evolved from operative to endovascular intervention. Benefits of endovascular treatment included shorter convalescent times and less cranial nerve injury. Unfortunately, the authors did not describe the causes or the morphologic types of the treated aneurysms.

Conclusion

At present, the indications for intervention in patients with extracranial carotid aneurysms have not been com-pletely brought to light. In the event of symptoms, an intervention is clearly indicated. To date, the risk of complications of an asymptomatic aneurysm and its relation to issues like aneurysmal diameter and plaque instability have not been studied. The choice between endovascular repair and conventional surgery can de-pend on various factors, including the type of aneu-rysm, comorbidities, symptoms, and the experience and preference of the surgeon. The relatively low incidence of these lesions makes it difficult to obtain sufficient experience with endovascular procedures for carotid aneurysm. However, growing proficiency with carotid stenting for stenotic lesions might provide adequate in-terventional skills.

In summary, we have shown that interposition graft-ing of large atherosclerotic carotid aneurysms can be safe, but that there is a risk of cranial nerve injury. There were no strokes or major neurologic complications in our 3 patients. Controlled comparative studies of endo-vascular treatment are a challenge for the future; how-ever, the low incidence of lesions will complicate the design of such studies.

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