Neurology India Medknow Publications on behalf of the Neurological Society of India ISSN: 0028-3886 EISSN: 1998-4022 Vol. 59, Num. 4, 2011, pp. 537-541

Neurology India, Vol. 59, No. 4, July-August, 2011, pp. 537-541

Original Article

Radial artery grafts for symptomatic cavernous carotid aneurysms in elderly patients

Yasuo Murai¹, Takayuki Mizunari², Katsuya Umeoka², Kojiro Tateyama¹, Shiro Kobayashi², Akira Teramoto¹

¹ Department of Neurosurgery, Nippon Medical School, Japan
² Department of Neurosurgery, Neurological Institute, Nippon Medical School Chiba Hokusoh Hospital, Chiba, Japan
Correspondence Address: Yasuo Murai, 1-1-5, Sendagi, Bunkyo-ku-Japan, Japan, ymurai@nms.ac.jp

Date of Submission: 03-Feb-2011
Date of Decision: 28-Feb-2011
Date of Acceptance: 02-Apr-2011

Code Number: ni11166

PMID: 21891929

DOI: 10.4103/0028-3886.84333

Abstract

Background: Radial artery grafts (RAG) have been used in the treatment of complex vascular lesions, but not for symptomatic cavernous carotid aneurysms in elderly patients.
Aim: To investigate the safety, usefulness, and perioperative complications of RAGs for symptomatic cavernous carotid aneurysms in elderly patients.
Material and Methods: Of the 74 consecutive patients, in whom RAGs were used, we retrospectively investigated the postoperative outcomes and complications in eight elderly patients aged over 70 years with symptomatic internal carotid artery aneurysms in cavernous sinus.
Results: Postoperative complications included one case of cerebral infarction, one case of symptomatic seizures, and one case of delayed cranial nerve palsy.
Outcome: Seven patients had an mRS score of 0, and one patient had a score of 2. Postoperatively there was improvement in cranial nerve palsy in seven patients and the patients who had symptoms for one year and eight months had residual deficits. Although it cannot be stated that the frequency of perioperative complications was low, the final outcomes were favorable.
Conclusion: Even in carotid disease that is difficult to treat among the elderly, RAG would appear to be a useful and safe treatment.

Keywords: Bypass, carotid artery, cavernous sinus, cerebral aneurysm, radial artery

Introduction

In recent years, with the advances in diagnostic neuroimaging, several authors have reported the early detection and treatment outcomes of asymptomatic unruptured cerebral aneurysms. ^{[1],[2],[3],[4]} The factors that determine the surgical treatment strategies in non-ruptured aneurysms include: Age, number, size, and site of the aneurysms, family history, and medical history. However, it is not clear how aggressive one should be in symptomatic large cavernous carotid aneurysms in elderly patients. Cavernous carotid aneurysms are already large by the time they are detected and often present with minor neurological symptoms such as blepharoptosis, polyopia, and opthalmalgia. ^{[3],[4],[5],[6]} Often the management approach for such a clinical condition would be a diligent follow-up, rather than being aggressive and carrying out a highly invasive and technically difficult surgery for a lesion with mild symptoms, in elderly patients. ^[7]

Various treatment strategies adopted for large giant aneurysms in the cavernous sinus include: Revascularization using the saphenous vein ^[8] or the radial artery, ^{[7],[9],[10],[11]} simple proximal internal carotid artery occlusions, ^[12] endovascular treatment, ^{[13],[14],[15]} and a combination of these strategies. We have successfully used a high flow bypass, using the radial artery, while treating the case of a complex internal carotid artery aneurysm, where we found difficulty in clipping the aneurysm directly. ^[3] Subsequently, the successful use of the radial artery graft has been documented. ^{[11],[12],[13],[14],[15],[16]} There are several reports of the successful use of a high flow bypass (HFB) in the treatment of cerebral aneurysms. ^{[7],[8],[9],[10]} However, there are no reports regarding its indications in elderly patients. In this report we investigated the results of the radial graft in elderly patients over 70 years of age, with large symptomatic cavernous carotid aneurysms.

Material and Methods

Subjects

Eight patients aged over 70 years operated (from 1997) for large or giant symptomatic cerebral cavernous carotid aneurysms were included in the study [Table - 1]. There were three male cases and five female cases and the mean age was 72.5 years (range 70 - 78 years). At least one risk factor was present in all the patients, including hypertension (5/8), cigarette smoking, hyperlipidemia (1/8), and diabetes mellitus, with obesity (2/8). None of the patients had either symptomatic or asymptomatic carotid stenosis. The clinical features included: Oculomotor palsy (5), abducens nerve palsy (2), cephalalgia (1), and visual field defects (1).

High flow bypass (HFB) surgery was performed in all the patients scheduled for the surgical ligation of the internal carotid artery (ICA). This approach was adopted, as the cerebral blood flow (CBF) study with or without the acetazolamide challenge, along with the balloon occlusion test (BOT) were not reliable enough to determine whether the ICA could be safely ligated without exposing the patient to the risk of short- or long-term cerebral ischemia or de novo formation of aneurysms, ^{[7],[9],[17],[18],[19],[20]} as also, there was about a 3% risk of complications associated with these procedures.

The radial artery graft (RAG) technique used in this study was based on the method reported by Kamiyama et al.^{[3],[9],[11],[16],[19]} This technique consisted of the following essential points in order to surgically achieve a high-flow bypass using RAG: (1) RAG was used for anastomosis between the external carotid artery (ECA) and the middle cerebral artery (MCA); (2) liquid angioplasty of the extracted radial artery was performed using heparinized saline pressure distention; ^{[3],[7],[9],[10],[11],[19]} (3) the ICA was simultaneously ligated using a 1-0 suture, (4) reconstruction of the radial artery was performed using a concomitant vein; ^{[3],[9],[11],[21],[19]} and (5) the pressure of the MCA was monitored via the superficial temporal artery (STA) to MCA anastomosis. Indocyanine green video angiography, motor-evoked potentials, and Doppler were used to check the patency of the RAG. ^{[3],[9],[11],[19]} The STA-MCA bypass using RAG was basically used in all the patients for the following reasons ^{[3],[9],[11],[19]} : The main purpose of the STA-MCA bypass was to monitor the pressure of the MCA via the STA (the so-called 'double insurance bypass'). ^[22],[23] Therefore, intraoperative monitors were needed to confirm the adequacy of the bypass perfusion pressure.

Anti-coagulant therapy was used to avoid ischemic complications during surgery if patients were taking antiplatelet or anticoagulant drugs due to a previous history of cerebral infarction or myocardial infarction. In the perioperative period, the patients were not put on anticoagulant therapy or antiplatelet therapy. As a rule, we changed to cilostazol prior to surgery, and stopped it a day before surgery. After computed tomography (CT) imaging one day post surgery, we restarted the administration of the drug two days post surgery. Diffusion weighted imaging and magnetic resonance angiography were done within four days of the surgery, to detect ischemic complications. The patency of the vascular graft was confirmed by 3D computed tomography angiography within five days of surgery. Patients were evaluated for any neurological deficits preoperatively, postoperatively, and during follow-up in the outpatient clinic. Magnetic resonance angiography (MRA) and MR imaging (MRI) were performed every six months for one year and every 12 months thereafter, to detect new ischemic events, de novo aneurysms, or RA graft stenoses.

Results

The preoperative clinical features, postoperative outcomes, and complications are given in [Table - 1]. The preoperative symptoms and signs improved within two months of surgery, except in one patient who had symptoms of 18 months' duration before surgery. At the six-month follow-up the modified Rankin Scale (mRS) ^[24] scores were: mRS 2 − one patient and mRS 0 − six patients. The mean follow-up period was 37.8 months (range: 11 - 142 months). One patient died from acute myocardial infarction three-and-a-half years after RAG. One patient had postoperative cerebral infarction (Case 6) and another patient developed convulsive seizures, which had been attributed to the postoperative hyperperfusion syndrome (Case 7). One patient developed abducens nerve palsy three months after the surgery, and it took approximately one-and-a-half months to improve.

Illustrative cases

Case 6

A 73-year-old female presented with right occulomotor nerve palsy due to a cavernous carotid aneurysm of three months' duration [Figure - 1]. She had an ECA-RA-MCA bypass and a ligature of the cervical internal carotid artery. The average blood pressure of the cortical MCA through STA was around 80% of the systemic blood pressure. MRA done on the second day of the surgery confirmed the favorable bypass blood flow [Figure - 2] and diffusion weighted imaging (DWI) did not show any evidence of ischemia or hemorrhage [Figure - 3]. Five days post surgery she developed dysarthria, and gait disturbance appeared. A repeat DWI showed an acute infarct in the left medial frontal lobe [Figure - 4]. She was started on antiplatelet agents. She had good recovery of her neurological deficits over 20 days post surgery and was discharged on day 30 post surgery, unaided.

Case 7

A 74-year-old male presented with right abducens nerve palsy due to a cavernous carotid aneurysm of 18-months' duration. The patient had been explained about the chances of improvement of cranial nerve symptoms in view of the longstanding symptoms and was taken up for surgery, after his consent. He had an ECA-RA-MCA bypass and a ligature of the cervical internal carotid artery. The mean blood pressure of the cortical MCA through STA was around 95% of the systemic blood pressure. A brain CT done on day one post surgery showed no ischemic or hemorrhagic events. DWI, done two days post surgery did not reveal any acute ischemic changes. Digital subtraction angiography confirmed favorable bypass blood flow. Iodoamphetamine-single photon emission computed tomography (IMP SPECT) [Figure - 5] done five days post surgery showed hyperperfusion in the right frontal lobe. He was started on phenytoin. The same night, he had recurrent generalized convulsive seizures (four) and subsequent altered mental status (JCSII-20), which lasted for two days. By the seventh postoperative day he was fully conscious and was left with mild amnesia. He was discharged on day 34 post surgery, unaided, but was left with short-term memory impairment. A post-surgical MRA demonstrated good graft patency with no de novo aneurysms [Figure - 6].

Discussion

In this study perioperative complications were mild, and long-term outcomes were satisfactory with ECA-RA-MCA bypass, using RAG as a treatment, for large or giant symptomatic cavernous carotid aneurysms, in elderly patients. The recovery of cranial nerve deficits was also high. Earlier we used RAG in complex vascular lesions of the brain in over 70 patients. ^[3] Of the 70 lesions, 31 were cavernous sinus lesions and 24 cases were under 70 years of age. Excluding the cranial nerve palsy related to ligature of the ICA, the complications included one case of symptomatic seizures and one case of epidural hematoma. As the number of cases in the study was so few, it would be difficult to make a comparison, but it appeared that the acute complication rates might be similar between young and old patients with this lesion.

One of our patients had delayed abducens nerve palsy during follow-up. Delayed palsy of the cranial nerves traversing the cavernous sinus has been documented with ligature of the internal carotid artery in the neck. ^{[3],[16],[18],[24]} In a series by Field et al., ^[18] 27% of the patients developed a new onset of cranial nerve palsy post surgical carotid ligature and this has been attributed to ischemic injury of the cranial nerves due to involvement of the meningohypophysial trunk and the vasa nervorum from the internal carotid artery to the cranial nerves in the cavernous sinus. Earlier, we have also reported such delayed cranial neuropathy with this surgery, ^[3],[16] and one should be aware of this complication with this surgery and look for it. Most often cranial nerve palsies are transient and improve in a majority of cases. ^[18] When similar symptoms emerged, Arimura et al. ^[19] reported a case of cranial nerve palsy, wherein they performed additional distal internal carotid artery occlusion without confirming the enlargement of the aneurysm. We believe that no additional treatment is required in patients with this complication unless there is enlargement of the aneurysm. Of the various types of cerebral revascularization procedures, revascularization using the radial artery in particular, rather than the internal carotid artery, is the procedure associated with lower blood flow. ^[25],[26] With this procedure the need for additional treatment is extremely low. ^[20],[23] If a saphenous vein is used, depending upon the thickness of the vessel there may be a need for the use of antiplatelet agents or anticoagulants. However, there is no data on this aspect. One has to differentiate whether the new symptoms are due to worsening of symptoms present before surgery or new symptoms related to the surgery. ^[18] If, the symptoms are due to the pressure effect of the aneurysm, there will be worsening of cranial nerve palsies, because of the growth of the aneurysm.

Use of the radial artery and sephenous vein in the treatment of internal carotid cavernous aneurysms is not rare. ^{[7],[8],[9],[10],[11]} However, there have been no studies of their use in the treatment of these vascular lesions in the elderly, as also the associated complications. Some of the earlier studies included only few subjects aged over 70 years. ^{[7],[17],[21],[26],[27]} Our study shows that RAG is a safe and useful method of treatment even in the elderly of over 70 years. However, one should keep in mind the high risk of vascular events in the perioperative period in this age group, and should use antiplatelet agents judiciously and appropriately. These patients may have cerebral hemodynamic changes in the perioperative period and should carefully be monitored with perfusion MRI, perfusion CT, and SPECT, as the situation demands.

Acknowledgments

This study was supported by a grant from the Hakujikai Institute of Gerontology (Tokyo, Japan).

References

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