Clinical Outcome and Ischemic Complication after Treatment of Anterior Choroidal Artery Aneurysm: Comparison between Surgical Clipping and Endovascular Coiling

BACKGROUND AND PURPOSE: Although coiling has been favorably comparable with clipping for treatment of most intracranial aneurysms, there is a controversy on which modality is safer for anterior choroidal artery (AchoA) aneurysm. We retrospectively evaluated the clinical outcomes and treatment-related complications after surgical clipping and endovascular coiling of AchoA aneurysms. MATERIALS AND METHODS: Seventy-three AchoA aneurysms were recruited from 1895 intracranial aneurysms, which were treated either by surgical clipping or by endovascular coiling in 4 institutions between May 1999 and December 2006. The AchoA aneurysms were dichotomized according to the modality of treatment, the coil group (37 patients; 38 aneurysms) and the clip group (35 patients; 35 aneurysms). Clinical outcomes and incidence of treatment-related complications between 2 groups and the factors influencing the clinical outcomes were evaluated. RESULTS: There was no rebleeding in both groups during follow-up, for 4–72 months (mean, 27 months) in the coil group and for 3–84 months (mean, 34 months) in the clip group. In the coil group, 31 patients (83.8%) had favorable outcome (modified Rankin Scale score [mRS], 0–3). In the clip group, 31 patients (88.6%) had favorable outcome. The complication of coiling was transient contralateral hemiparesis in 2 patients, who recovered completely. The complications of clipping were permanent contralateral hemiparesis due to AchoA infarction in 4 patients and third-nerve palsy in 1 patient. Hunt and Hess grade 4 or 5 and AchoA infarction were significantly correlated with poor outcome (mRS, ≤4). Clipping had significantly higher incidence of AchoA infarction than coiling (P < .05). CONCLUSION: Coiling of AchoA aneurysms appears comparable with clipping in clinical outcome and prevention of rebleeding, with significantly lower incidence of AchoA infarction than clipping.

A nterior choroidal artery (AchoA) aneurysms are relatively rare and account for 2%-5% of all intracranial aneurysms. 1 Because AchoA is a small branch, but supplies critical territory, including posterior limb of the internal capsule, impairment of this artery may produce debilitating postoperative AchoA syndrome, including contralateral hemiparesis. The mortality rate and the treatment-related permanent morbidity rate of surgical clipping of AchoA aneurysms range from 6% to 33% and 10% to 28.6%, respectively. [2][3][4][5] To our knowledge, there has been only 1 small series focused on coiling of the AchoA aneurysms. 6 The purpose of this study was to retrospectively evaluate and compare the clinical outcomes and treatment-related complications after surgical clipping and endovascular coiling of AchoA aneurysms.

Materials and Methods
The institutional review boards of the 4 hospitals approved this retrospective study, and informed consent was not required. Seventy-three AchoA aneurysms were recruited from 1895 intracranial aneurysms, which were treated either by surgical clipping or by endovascular coiling in 4 institutions between May 1999 and December 2006. One patient had bilateral AchoA aneurysms. The aneurysms were sorted into 2 groups according to the technique of treatment, the coil group and the clip group. The coil group (n ϭ 38; ruptured ϭ 23; unruptured ϭ 15) was composed of those who underwent endovascular coiling and included 14 men and 23 women with ages ranging from 23 to 78 years (mean, 54 years). The clip group (n ϭ 35; ruptured ϭ 30; unruptured ϭ 5) was composed of those who underwent surgical clipping and included 15 men and 20 women with ages ranging from 25 to 63 years (mean, 45 years). Aneurysms associated with arteriovenous malformation and aneurysms involving distal AchoA were excluded. Informed consent was obtained and preceded treatment. An interventional neuroradiologist and a neurosurgeon reviewed the angiograms, operative records, and medical records to obtain the relevant clinical and angiographic information.

Coil Embolization and Surgical Clipping
Coiling was conducted under general anesthesia. Anticoagulation was initiated by injection of a bolus of 3000 -5000 IU of heparin intravenously at the beginning of the procedure, followed by continuous infusion of heparin by rate of 1000 IU/h. Heparin was continued for 24 -48 hours after embolization. Activated coagulation time was maintained between 2 and 3 times above the normal value. Coiling was generally performed by a standard single-microcatheter technique. Double-microcatheter technique was used in 4 aneurysms due to the wide neck and/or incorporation of the AchoA into the aneurysm (Fig 1). Stent-assisted technique was used in 2 aneurysms due to the wide neck.
Surgical clipping was performed with a standard technique. In most cases, microvascular Doppler ultrasonography was used to identify the flow into the AchoA. Monitoring of intraoperative motor-evoked potentials (MEPs) was not used.

Clinical and Angiographic Follow-up
The patients were clinically assessed before and after the treatment by the neurosurgeons and/or the interventional neuroradiologists. The coil group was clinically followed up for a mean Ϯ SE of 27 Ϯ 22 months (range, 4 -72 months) and the clip group for a mean of 34 Ϯ 25 months (range, 3-84 months).
Each patient's outcome at the latest clinical follow-up was evaluated and graded according to the modified Rankin scale score (mRS). 7 For the patients who were not followed up at our institutions, clinical outcome was evaluated with a telephone interview. If the patient's clinical condition became worse because of causes unrelated to the procedure or the aneurysm during the follow-up, the patient's outcome at discharge was determined as the final outcome.
In the coil group, angiographic follow-up after coiling was conducted as our routine schedule for intracranial aneurysms at the other sites. In the clip group, angiographic follow-up was not routinely performed.

Statistics
All of the statistical analyses were performed using SPSS for Windows (version 10.0; SPSS, Chicago, Ill). The factors influencing clinical outcome and treatment-related AchoA infarction were evaluated. Univariable analyses for age, sex, aneurysm size, neck type, presence of subarachnoid hemorrhage (SAH), Hunt and Hess grade, treatment modality, and treatment-related AchoA infarction were separately performed modeling poor outcome (mRS, Ն4) using a 2 test. All of the variables with P Ͻ .2 in univariable analysis were entered into separate multivariable logistic regression models. Incidence of treatment-related complications was compared between the coil group and the clip group by using a 2 test. Statistical significance was determined by P Ͻ .05 for a 95% confidence interval.

Characteristics of the Patients and AchoA Aneurysms: Coil Group Versus Clip Group
The coil group was significantly older in age than the clip group. There were no significant differences between the 2 groups in sex, size of aneurysms, diameter of aneurysm neck, incidence of rupture, and Hunt and Hess grade (Table 1).

Clinical Outcome
Clinical outcomes (mRS) are summarized in Table 2 according to the Hunt and Hess grading (HH) system and the treatment modality. None of the 72 patients treated either by coiling or by clipping rebled during follow-up. Of the patients with HH 0 -3, all (n ϭ 30) of those in the coil group had favorable outcome, whereas 2 patients in the clip group (n ϭ 32) had poor outcome (mRS, Ն4) due to treatmentrelated AchoA infarction to result in grade 2 contralateral hemiparesis.
HH 4 or 5 and treatment-related AchoA infarction were significantly correlated with poor outcome (P Ͻ .05). Age, sex, aneurysm size, neck type, presence of SAH, and the type of treatment modality were not significantly correlated with clinical outcome (Tables 3 and 4).

Treatment-Related Complications
In the coil group, transient AchoA flow insufficiency occurred in 5 patients during the procedure. However, the patency of the AchoA was restored within 30 minutes in all 5 of the patients by using intravenous bolus injection of 5000 IU of heparin (n ϭ 1), infusion of 5-10 mg of abciximab through the guiding catheter (n ϭ 2), or papaverine infusion through the microcatheter (n ϭ 2). In 2 of the 5 patients, transient contralateral hemiparesis occurred after the procedure but resolved within 1 week. Follow-up CT of the 2 patients revealed no evidence of AchoA infarction. The other 3 patients had no postprocedural adverse symptoms. In addition, there were no access related complications.
In the clip group, permanent contralateral hemiparesis due to the AchoA infarction occurred in 4 patients, and third-nerve palsy occurred in 1 patient (Table 5). All 4 of the patients with permanent contralateral hemiparesis revealed infarction in the posterior limb of ipsilateral internal capsule on CT (Fig 2). Clipping had significantly higher incidence of treatment-related AchoA infarction than coiling (Table 5).

Results of Follow-up Angiography
Twenty-nine aneurysms (76.3%) in 28 patients of the coil group were followed up with 1 or more angiographies. Recurrence was found in 5 (17.2%) of the 29 aneurysms in angiographic follow-up performed 6-45 months (mean Ϯ SE, 18 Ϯ 12) after treatment. Four recurrences were found in the first year of follow-up, and 1 in the second year. Of the 5 recurred aneurysms, a second coil embolization was performed with results of near-complete occlusion in 2 aneurysms, both of which were stable on the next 2 follow-up angiographies. The other 3 aneurysms were not retreated because of the small size of the recurrent sac.
Three patients of the clip group underwent immediate follow-up angiography on the following day after surgery due to symptoms of AchoA infarction. One patient revealed AchoA occlusion, and 2 patients revealed patent AchoA (Fig 2). No patient in the clip group underwent late follow-up angiography.     group in this study. Therefore, it may be required to routinely follow-up with angiography after coiling the AchoA aneurysm. In addition, because there is a small but significant risk of de novo aneurysm formation or growth of remnant aneurysm after clipping, clinical follow-up should be applied to both the coil group and the clip group over an extended period of time. 14,15 The results of this study suggest that coiling for AchoA aneurysms is comparable with clipping in clinical outcome and prevention of rebleeding, with significantly lower incidence of AchoA infarction, which will potentially result in poor outcome.