Intracranial aneurysms can be classified as saccular

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1 74 Fusiform Aneurysm of the Vertebrobasilar Arterial System Henry C. Echiverri, MD, Frank A. Rubino, MD, Sudha R. Gupta, MD, and Meena Gujrati, MD We retrospectively evaluated the clinical features and therapeutic outcomes in 3 consecutive patients with the of fusiform aneurysm of the vertebrobasilar system. Four patients (3%) presented with compressive symptoms and 0 (77%) with ischemic symptoms; one patient presented with both types of symptoms. No patient presented with rupture of the fusiform aneurysm. Based on the attending physician's choice, treatment included antiplatelet therapy in five patients, anticoagulation in seven, and no medication in one. Five patients died, four treated with antiplatelet agents and one not treated with any medication. The cause of death was progressive brainstem ischemia in three, sepsis in one, and gastrointestinal bleeding in one patient. All seven patients who received anticoagulants were alive, with no recurrence of symptoms or hemorrhagic complications after a mean follow-up period of 8 months. Based on previous and current series, we conclude that rupture of fusiform aneurysms is rare. Our results suggest a more favorable outcome in the management of these aneurysms with anticoagulation therapy to prevent progressive thrombosis and embolization. (Stroke 989;20:74-747) Downloaded from by on November 26, 208 Intracranial aneurysms can be classified as saccular aneurysms or fusiform aneurysms using shape as a criterion. The developmental origin of saccular aneurysms as due to a defect in the elastic and muscular coats of blood vessels has been widely accepted. - 3 Fusiform aneurysms, on the other hand, have been associated with atherosclerotic processes so that the term "atherosclerotic aneurysm" has been used interchangeably. 4-6 Because of the elongated and tortuous shapes of fusiform aneurysms, "dolichoectasia" is another term that has been used to describe them. 4 Review of previous studies indicates that fusiform aneurysms have been most frequently associated with compression, ischemia, or both and rarely with rupture. 5-8 Various articles have described the clinical course of fusiform aneurysms, 5-7 ' 9 ' 0 most in the vertebrobasilar system. However, none of these articles dealt with the aspect of treatment outcome. Only that of Nishizaki et al 5 comes close to hinting at the benefit of antiplatelet therapy; however, no justification was offered. Accordingly, we studied fusiform aneurysms of the vertebrobasilar system in 3 patients. We describe the clinical signs From the Departments of Neurology (H.C.E., F.A.R., S.R.G.) and Neuropathology (M.G.), Veterans Administration Hospital, Hines and Loyola University Medical Center, Maywood, Illinois. Address for reprints: Sudha R. Gupta, MD, Neurology Service, Hines Veterans Administration Hospital, Hines, IL 604. Received June 3, 989; accepted August 8, 989. and symptoms and the outcome and discuss the therapeutic options. Subjects and Methods We studied 3 consecutive patients with the of fusiform aneurysm seen at Hines Veterans Administration Hospital (Neurology Service), Hines, Illinois, between July 980 and June 988. The was made by computed tomography (CT) of the head, cerebral angiography, or magnetic resonance imaging (MRI). Fusiform aneurysm was defined as a fusiform and segmental dilatation and tortuosity of a blood vessel in the vertebrobasilar system. The medical records were reviewed to determine the presentation, clinical course, and therapy of fusiform aneurysm. Postmortem findings were reviewed for two patients. Results Table summarizes the clinical features of all 3 patients. Their ages ranged from 46 to 8 (mean 67) years old. There were two women and men. The presenting features were categorized as compressive (due to mass effect of the ectatic vessel) or ischemic (due to thrombosis or embolization of vessels) (Table 2). The duration of symptoms before varied from 2 days to 3 years (mean 20 months for compressive symptoms and 5 months for ischemic symptoms). Compressive symptoms occurred in four patients (3%) and included cranial nerve involvement in three and in

2 742 Stroke Vol 20, No 2, December 989 Downloaded from by on November 26, 208 TABLE. Pt/Age/Sex /72/M 2/70/M 3/57/F Clinical Features of 3 Patients With Vertebrobasiiar Fusiform Aneurysm Presenting symptoms Intermittent diplopia for 7 years; later persistent diplopia Progressive memory difficulty, staggering gait, and incontinence with headaches Headache, diplopia, and vertigo year prior; followed by confusion and gait difficulty. History of L thalamic hemorrhage 4 years prior 4/8/F Trigeminal neuralgia for 5 years; later gait difficulty, confusion, and incontinence 5/49/M 6/65/M 7/69/M 8/46/M Progressive ataxia, diplopia, vertigo, and R hemiparesis for year Ataxia, L face and R arm weakness year prior with residual L facial weakness; recurrent R-sided weakness Vertigo, headache, and emesis progressing to coma and quadriparesis Transient vertigo and L facial numbness week prior; followed by severe vertigo, headache, and gait ataxia 9/78/M Intermittent diplopia for 2 months followed by speech difficulty, L facial droop, and persistent diplopia 0/76/M L arm weakness and R facial numbness with dreamlike hallucinations month prior; then developing facial droop, speech difficulty, and vertigo /80/M Transient B blurred vision 3 days prior; leading to vertigo, environmental tilting to L, and headache 2/55/M Intermittent diplopia and memory difficulty, intermittent R facial twitching for 3 years; followed by diplopia 3/68/M Intermittent vertical diplopia and unsteady gait for 6 months; with worsening of symptoms Signs L VI nerve palsy Impaired recent memory, L lower motor neuron VII weakness and ataxia Confusion, disorientation, right miosis, L internuclear ophthalmoplegia, R corneal reflex depressed, R hemiparesis Lethargy, disorientation, and generalized weakness; progressed to deep stupor L IV nerve palsy, R hemiparesis Dysarthria, L supranuclear VII nerve palsy, R hemiparesis, and ataxia Comatose with eye deviation to L, downbeat nystagmus, facial diplegm, quadriparesis with B extensor toe signs Orthostatic hypotension, L Horner's syndrome, L facial and R body sensory deficit, and L limb and gait ataxia Dysarthria, R MLF syndrome, L motor sensory hemiparesis Dysarthria, R supranuclear VII nerve palsy, L XII nerve palsy, L motor hemiparesis, and R ataxia Body tilt to L, rotatory nystagmus on L gaze, B limb and gait ataxia Memory impairment, R VI nerve palsy, R hemifacial spasm B limb and gait ataxia, L hemiparesis Stroke risk factors HTN HTN, DM, polycythemia vera CAD, HTN CAD (atrial fibrillation) HTN, DM, CAD Radiology findings CT: ectatic vessels in posterior circulation with CT: brainstem infarction, ectatic basilar artery with Angiogram: ectatic basilar and carotid arteries CT: large ectatic basilar artery with CT year prior: L midbrain infarction with ectatic vessels Angiogram: ectatic carotid and basilar vessels CT: ectatic vessel in anterocentral brainstem extending to interpeduncular cistern and L thalamus with thrombosis on contrast; lucency in R pons extending inferiorly CT: calcified and enlarged vertebral and basilar arteries MRI: cerebellar infarction and brainstem compression with impingement on pontomedullary junction MRI: same plus infarction at L medial thalamus CT: cerebellar lucencies and ectatic vertebral vessels All patients were white. Pt, patient; M, male; F, female; L, left; R, right; B, bilateral; HTN, hypertension; DM, diabetes mellitus; MLF, medial longitudinal fasciculus; CAD, coronary artery disease; CT, computed tomogram; MRI, magnetic resonance image.

3 Echiverri et al Fusiform Aneurysm 743 TABLE 2. Presenting Symptoms, Before Diagnosis of Fusiform Aneurysm in 3 Patients Presenting symptoms Compressive VI nerve palsy Trigeminal neuralgia Hemifacial spasm Hydrocephalus Ischemic Transient ischemic attack Stroke Hemorrhage Brainstem ischemia Thalamic infarction n Duration of symptoms mo 36 mo 6 mo 36 mo 5 3 days-6 mo 2 mo 2 days 36 mo 3 one. Ten patients (77%) presented with ischemic symptoms, five with transient ischemic attack and five with infarction. One patient (Case 2) had a combination of both compressive and ischemic symptoms, presenting with hemifacial spasm and thalamic infarct. Headache was a prominent feature in five patients (38%). One patient (Case 3) had a left thalamic hemorrhage which was thought to be due to hypertension, 2 months before the of fusiform aneurysm. Downloaded from by on November 26, 208 FIGURE 2. Cerebral angiogram showing dilatation and tortuosity ofbasilar artery in Case 2. FIGURE. Computed tomogram of head, with contrast showing ectatic vertebrobasilar artery. Giant ectatic basilar artery is seen compressing brainstem and fourth ventricle in Case 2. Fusiform aneurysm was best visualized on CT scan with contrast infusion (Figure ). Occasionally, the ectatic vessel attained giant proportions, being large enough to cause a mass effect and obstruct the fourth ventricle, causing. Cerebral angiography in six patients demonstrated a fusiform dilatation of the vessel (Figure 2). In two patients, concomitant ectasia of the carotid circulation was also seen. MRI was obtained in two patients, and the ectatic vessel was demonstrated as a negative signal. Figure 3 is the MRI of Case 2, which also shows thalamic infarction. After the initial presentation, before the of fusiform aneurysm, 9 patients were treated with antiplatelet medication; the dosage of aspirin ranged from 325 mg/day (one tablet) to,300 mg/day (two tablets twice a day). After the was made, five patients were maintained on antiplatelet therapy and seven were treated with an anticoagulant (warfarin) to maintain a prothrom-

4 744 Stroke Vol 20, No 2, December 989 FIGURE 3. Tl-weighted magnetic resonance image of Case 2 showing signal-void ectatic vessel anterior to brainstem (large arrow) and left thalamic infarction (small arrow). Coronal view. Downloaded from by on November 26, 208 bin time of.5xcontrol. The treatment choice was the attending physician's decision. One patient did not receive any antiplatelet or anticoagulant therapy before or after the due to the presence of gastrointestinal (GI) malignancy. One patient receiving aspirin both before and after the also had a ventricular peritoneal shunt placed for. Outcome and follow-up status of all patients are summarized in Table 3. Five patients died, two of brainstem infarction, one of with sepsis, one of brainstem infarction and, and one of GI bleeding. The remaining eight patients were alive with various residual deficits and had no recurrence or progression of symptoms. Seven of these eight patients received anticoagulant therapy, and one (Case 5) was not treated with anticoagulants due to the presence of concomitant carotid artery ectasia. The duration of follow-up after the ranged from 9 to 36 (mean 8) months for the eight survivors. During the followup period, hemorrhagic complications from therapy, rupture of the fusiform aneurysm, or recurrent ischemia were not present. Postmortem examination was available in two patients. Figure 4 illustrates the thrombosed aneurysm and the extensive pontine infarction with demyelination in Case. The autopsy on Case 3 showed a fresh infarct in the pons and old cerebellar infarcts. There was thrombosis within the ectatic vessel. Discussion The initial event in the formation of fusiform aneurysm is thought to be lipid deposition in and beneath the intima that disrupts the internal elastic membrane and infiltrates the muscular wall.-3' The resultant atrophy of the elastic substance and the musculature then leads to tortuosity of the vessel due to intravascular pressure,4-62 causing the ectatic vessel to expand in diameter and length. Unlike the focal outpouchings found in saccular aneurysms, in fusiform aneurysms the entire vessel expands, which supports the observation that deficiency of the muscular wall and internal elastic lamina is diffuse. The circulation slows because of this increased luminal diameter, and the resulting turbulent blood flow predisposes the vessel to thrombosis, which promotes further intimal disruption and vessel distortion.6-8 Repeated thrombosis near the wall makes the vessel stiff and thick. The natural tendency then for a fusiform aneurysm is to expand and produce mass effects on nearby structures. Or, the expanding fusiform aneurysm can distort vascular branches, reducing distal flow, or can even serve as a nidus for clot formation and distant embolization.5'8-3-6 The risk of rupture of the fusiform aneurysm and hemorrhage is reduced due to the diffusely thickened and stiff wall. The initial presentation of sixth nerve palsy due to mass effect and finally brainstem infarction in Case illustrates the sequelae. The clinical features of fusiform aneurysm have been studied by various investigators,7'8 who divided them into three categories: ischemic; cranial nerve compression; and "pseudotumoral," when the fusiform aneurysm compresses vital structures other than cranial nerves. No hemorrhage due to rupture of vertebrobasilar fusiform aneurysm was reported in their series. Yu et al9 studied 7 cases of vertebrobasilar fusiform aneurysm and found nine with brainstem ischemia and six with compressive symptoms. In addition, Yu et al9 also found three cases of subarachnoid hemorrhage (SAH), one from an associated saccular aneurysm of the anterior communicating artery and two with concomitant carotid fusiform aneurysm. The other two patients may have bled from a concomitant carotid fusiform aneurysm since there is evidence that they are more prone to bleed than are vertebrobasilar fusiform aneurysms.2 Nishizaki et al5 studied 23 cases of vertebrobasilar fusiform aneurysm and divided the initial symptoms into ischemic and mass effects. Intracranial hemorrhage was described in only three patients, one of whom experienced a hypertensive cerebellar hemorrhage; the other two patients had saccular aneurysmal hemorrhages. Recently, Pessin et al0 reported seven patients with brainstem infarctions with vertebrobasilar fusiform aneurysms. The mechanisms of infarction were described as intraluminal thrombosis, local

5 Echiverri et al Fusiform Aneurysm 745 Downloaded from by on November 26, 208 TABLE 3. Pt Course and Treatment in 3 Patients After Diagnosis of Fusiform Aneurysm Clinical course after presentation (last admission) VI nerve palsy leading to brainstem and cerebellar infarction Worsening Bilateral pontine infarction with worsening Worsening L midbrain infarction Recurrent brainstem infarction after warfarin was stopped prior to cataract surgery Progressed from coma to partial locked-in state L lateral medullary infarction R pontine infarction Medullary infarction Cerebellar infarction R VI nerve palsy, hemifacial spasm, and L thalamic infarction Pontocerebellar infarction Pt, patient; L, left; R, right. Before embolism, atherostenosis, and obstruction of the paramedian penetrating arteries. SAH was seen in only one patient, whose fusiform aneurysm rapidly ruptured; both intracranial carotid circulations were dilated in this patient. These studies, in addition to our current series, indicate the rarity of hemorrhage in vertebrobasilar fusiform aneurysm. We saw compressive symptoms in four and ischemic symptoms in 0 patients; one patient exhibited both types of symptoms. Hemorrhage, which appeared to be unrelated to the fusiform aneurysm because of its location and a history of hypertension, was seen in only one patient (Case 3). Compression of nearby structures has also been described in single case reports Four patients in our series presented with such symptoms. The Treatment After, ventriculoperitoneal shunt Outcome Died 5 years after Died of unrelated upper gastrointestinal bleeding (cancer) month after Died 2 years after Died 2 years after Alive, no progression at 9 Alive, residual L VII nerve palsy at 3 years follow-up Alive, no progression at 2 years follow-up Alive, no progression, with residual mild sensory and gait problem at 2 years follow-up Alive, no progression, improving eye movement at 3 Alive, no progression, slight L hemiparesis at Alive, no progression, residual L ataxia at 9 Alive, no progression at Died month after thalamic infarct in Case 2 represented ischemia due to distant embolization from the vertebrobasilar fusiform aneurysm, illustrated by the MRI findings showing a dilated vessel and an infarct in the thalamus (Figure 3). The duration of symptoms before the of fusiform aneurysm varied depending upon the type of symptoms. A longer duration was seen in patients presenting with compressive symptoms than in those presenting with ischemic symptoms. Similar results were observed by Boeri and Passerini. 6 It is possible that the delay between onset of symptoms and among patients with compressive symptoms is due to the time taken for the fusiform aneurysm to slowly enlarge and produce compression. While there appears to be a consensus on the pathophysiologic mechanisms of vertebrobasilar fusi-

6 746 Stroke Vol 20, No 2, December 989 FIGURE 4. Photomicrographs of (top): cut section of dilated vertebrobasilar artery showing intraluminal thrombosis. Hematoxylin and eosin stain. Bottom: microscopic view showing extensive infarction and demyelination at region of compression ofpons. Kluver-Barrera stain. (Original magnification, x4.) Downloaded from by on November 26, 208 form aneurysm, there is no general agreement regarding the treatment, nor have consistently successful results been reported in the literature. In the study of Yu et al, 9 two of nine patients with ischemia were treated with anticoagulants. All seven untreated patients died of progressive brainstem ischemia, but the two anticoagulated patients were alive at the 0-year follow-up. The overall mortality in that series was 63%. Those patients with compressive symptoms went on to develop brainstem ischemia or a progressive mass effect due to the fusiform aneurysm. Nishizaki et al 5 suggested the use of antiplatelet therapy in all patients with vertebrobasilar fusiform aneurysm, even those without ischemic symptoms. No follow-up of their patients is available. In our series, seven patients treated with anticoagulants remained alive for a mean of 8 months, with residual neurologic deficits but without any recurrence of their symptoms. In one of these patients, when anticoagulation was stopped for cataract surgery, the symptoms recurred. After resuming anticoagulation, no further recurrence had occurred at 36. Although antiplatelet therapy has been used to prevent thrombosis and embolization, our data show that despite receiving this therapy, four of nine

7 Downloaded from by on November 26, 208 patients went on to develop ischemic symptoms that required switching to anticoagulation. Of the remaining five patients, four died, three of progressive brainstem infarction. Since rupture and hemorrhage are rare, these results show a more favorable outcome of vertebrobasilar fusiform aneurysm with anticoagulation therapy. Although ours was not a controlled or double-blind study, it is a relatively large series of cases with retrospective analysis that suggests that anticoagulation is perhaps better than antiplatelet therapy. However, without a properly controlled, randomized, and long-term study, no definite recommendations can be reasonably proposed at this time. Hemorrhage, either due to rupture of the vertebrobasilar fusiform aneurysm or as a complication of anticoagulation, was not seen at all in our study; neither was it reported in the series of Yu et al 9 or Nishizaki et al. 5 Whenever hemorrhage was seen in those patients, a separate cause, such as concomitant saccular aneurysm, carotid fusiform aneurysm, or uncontrolled hypertension, was evident. References. Crawford T: Some observations on the pathogenesis and natural history of intracranial aneurysms. / Neurol Neurosurg Psychiatry 959;22: Burger P, Vogel F: Cerebrovascular disease. Am J Pathol 978;92: duboulay G: Some observations on the natural history of intra-cranial aneurysms. BrJ Radiol 965;38: Sacks J, Linderberg R: Dolichoectatic intracranial aneurysms. Johns Hopkins Med J 969;25:95-06 Echiverri et al Fusiform Aneurysm Nishizaki T, Tamaki N, Takeda N, Shirakuni T, Kondoh T, Matsumoto S: Dolichoectatic basilar artery: A review of 23 cases. Stroke 986;7: Boeri R, Passerini A: The megadolichobasilar anomaly. J Neurol Sci 964;l: Mosely I, Holland I: Ectasia of the basilar artery: The breadth of the clinical spectrum and diagnostic value of computed tomography. Neuroradiology 979;8: Caplan L: Miscellaneous cerebrovascular conditions. Semin Neurol 986;6: Yu Y, Mosely I, Pullicino P, McDonald W: The clinical picture of ectasia of the intracerebral arteries. / Neurol Neurosurg Psychiatry 982;45: Pessin MS, Chimowitz MI, Levine SR, Kwan ES, Adelman ES, Earnest MP, Clark DM, Chason J, Ausman JI, Caplan LR: Stroke in patients with fusiform vertebrobasilar aneurysm. Neurology 989;39:6-2. Hegedus K: Ectasia of the basilar artery with special reference to possible pathogenesis. Surg Neurol 985;24: Little J, St Louis P, Weinstein M, Dohn D: Giant fusiform aneurysm of the cerebral arteries. Stroke 98;2: Nijensohn D, Saez R, Reagan T: Clinical significance of basilar artery aneurysms. Neurology 974;24: Graff-Radford N, Adams H Jr, Smoker W, Biller J, Boarini D: Unruptured aneurysms of the posterior circulation with thalamic infarction. Neurosurgery 985;7: Steele J, Thomas H, Strollo P: Fusiform basilar aneurysm as a cause of embolic stroke. Stroke 982;3: Antune J: Cerebral emboli from intracranial aneurysms. Surg Neurol 976;6: Hilton G, Hoyt W: An atherosclerotic chiasmal syndrome. JAMA 966;96: Ekbom K, Greitz T, Kugelberg E: Hydrocephalus due to ectasia of the basilar artery. J Neurol Sci 969;8: KEY WORDS arteriosclerosis vertebrobasilar circulation cerebral aneurysm