Dissecting aneurysms of the anterior cerebral artery and accessory middle cerebral artery. Case report

A 66-year-old woman presented with dissecting aneurysms of the anterior cerebral artery (ACA) and accessory middle cerebral artery (MCA) manifesting as subarachnoid hemorrhage but without radiological evidence of the dissecting aneurysms. Intraoperative observation revealed that the vessel walls were dark purple in color, a typical finding of dissecting aneurysm. The abnormal A1 segment was trapped and the dissecting aneurysm of the accessory MCA was wrapped. In the case of SAH of unknown origin, dissecting aneurysm should always be kept in mind even if the angiogram does not show any abnormal finding. This is the first reported case of dissecting aneurysm of the accessory MCA.     

Endovascular occlusion of intracranial vessels for curative treatment of unclippable aneurysms: report of 16 cases

Among 121 intracerebral aneurysms presenting at one institution between 1984 and 1989, 16 were treated by endovascular means. All 16 lesions were intradural and intracranial, and had failed either surgical or endovascular attempts at selective exclusion with parent vessel preservation. The lesions included four giant middle cerebral artery (MCA) aneurysms, one giant anterior communicating artery aneurysm, six giant posterior cerebral artery aneurysms, one posterior inferior cerebellar artery aneurysm, one giant mid-basilar artery aneurysm, two giant fusiform basilar artery aneurysms, and one dissecting vertebral artery aneurysm. One of the 16 patients failed an MCA test occlusion and was approached surgically after attempted endovascular selective occlusion. Treatment involved pretreatment evaluation of cerebral blood flow followed by a preliminary parent vessel test occlusion under neuroleptic analgesia with vigilant neurological monitoring. If the test occlusion was tolerated, it was immediately followed by permanent occlusion of the parent vessel with either detachable or nondetachable balloon or coils. The follow-up period ranged from 1 to 8 years. Excellent outcomes were obtained in 12 cases with complete angiographic obliteration of the aneurysm and no new neurological deficits and/or improvement of the preembolization symptoms. Four patients died: two related to the procedure, one secondary to rupture of another untreated aneurysm, and the fourth from a postoperative MCA thrombosis after having failed endovascular test occlusion. The angiographic, clinical, and cerebral blood flow criteria for occlusion tolerance are discussed.     

Dissecting aneurysm of basilar artery presenting with recurrent subarachnoid hemorrhage

Spontaneous basilar dissecting aneurysms secondary to subarachnoid hemorrhage are rare, usually presenting with ischemia rather than a subarachnoid hemorrhage (SAH). A 63-year-old man who had SAH repeatedly from a ruptured basilar dissecting aneurysm was treated with endovascular occlusion of the unilateral vertebral artery. Postoperative angiograms 1 month after the procedure showed complete obliteration of the aneurysm. The clinical follow-up at 20 months showed no evidence of recurrent hemorrhage. Received: 24 August 1998 / Accepted: 15 December 1998     

Spontaneous dissecting aneurysm of middle cerebral artery: a case report with review of the literature.

We report a case of a dissecting aneurysm of the middle cerebral artery (MCA) and its treatment strategies. A 50-year-old male patient presented with occipital and neck pain for 2 days. CT scan revealed subarachnoid hemorrhage (SAH) in the region of the right sylvian fissure. A left carotid angiogram showed a dissecting aneurysm of the left MCA (M1). He was treated surgically by a pterional trans-sylvian approach. Clipping was done along with additional reinforcement by wrapping to completely obliterate the neck of the aneurysm. On reviewing the literature, we think that dissecting aneurysms seem to be one of the important causes of SAH and cerebral infarction of unverified origin. If an MCA dissecting aneurysm is identified, especially located in the proximal portion, surgical treatment must be considered. These patients merit a close follow-up.     

Case of spontaneous bilateral VA dissecting aneurysm presenting with SAH

We report a case of bilateral vertebral artery (VA) dissecting aneurysm presenting subarachnoid hemorrhage (SAH). It was difficult to decide which side was responsible for SAH because the patient's symptom and head CT suggested that the left VA aneurysm had ruptured, but angiography and MRA showed an irregular pearl and string sign on the right side. He was successfully treated by trapping of the right VA dissecting aneurysm and we confirmed by intraoperative evaluation that the right VA dissecting aneurysm had ruptured. The left unruptured aneurysm decreased its size spontaneously. In the treatment of the bilateral VA dissecting aneurysms, angiography needs to be performed over and over again because contralateral unruptured aneurysm may grow or rupture due to increased hemodynamic stress. Various combinations of direct sugery with or without arterial reconstruction and endovascular treatment should be considered when treating bilateral VA dissecting aneurysms.     

Outcome for unruptured middle cerebral artery aneurysm treatment: surgical and endovascular approach in a single center

The rupture of an intracranial aneurysm leads to subarachnoid hemorrhage (SAH). To prevent SAH, unruptured lesions can be treated by either endovascular or microsurgical approach. Due to their complex anatomy, middle cerebral artery (MCA) aneurysms represent a unique subgroup of intracranial aneurysms. Primary objective was to determine radiological and clinical outcomes in patients with middle cerebral artery aneurysms who were interdisciplinary treated by either endovascular or microsurgical approach in a single center. Secondary objective was to determine the impact of the lesions’ angiographic characteristics on treatment outcome. Clinical and radiological data of 103 patients interdisciplinary treated for unruptured MCA aneurysms over a 5-year period were analyzed in endovascular (n?=?16) and microsurgical (n?=?87) cohorts. Overall morbidity (Glasgow Outcome Score <5) after 12-month follow-up was 9 %. There was no significant difference between the two cohorts. Complete or “near complete” aneurysm occlusion was achieved in 97 and 75 % in the microsurgical, respective endovascular cohort. A “complex” aneurysm configuration had a significant impact on complete aneurysm occlusion in both cohorts, however, not on clinical outcome. Treatment of unruptured MCA aneurysms can be performed with a low risk of repair using both approaches. However, the risk for incomplete occlusion was higher for the endovascular approach in this series.     

Subarachnoid hemorrhage in the presence of both intracranial dissecting and saccular aneurysms--two case reports

Two patients presented with subarachnoid hemorrhage (SAH) associated with both intracranial dissecting and saccular aneurysms. Case 1, a 48-year-old woman, had a saccular aneurysm of the right internal carotid artery and dissecting aneurysms of the bilateral vertebral arteries. Case 2, a 52-year-old man, had three saccular aneurysms in the anterior circulation and a dissecting aneurysm of the unilateral vertebral artery. A saccular aneurysm was responsible for the SAH in both patients. Ruptured saccular aneurysms were treated with surgical clipping and unruptured dissecting aneurysms remained untreated. SAH recurred due to bleeding from an untreated dissecting aneurysm 4 days after the initial SAH in Case 1. Triple-H therapy, which causes increased hemodynamic stress, was not administered for symptomatic cerebral vasospasm after SAH in Case 2, because of the risk of bleeding from the untreated dissecting aneurysm, and the patient suffered cerebral infarction. The risk factors for this rare association are unclear, but both patients were smokers and had hypocholesterolemia including low apolipoprotein E levels. The clinical management of patients with SAH and both dissection and saccular aneurysms is complicated. Asymptomatic dissecting aneurysm has a benign clinical course in general, but hemodynamic stress related to stroke may induce abrupt development of dissecting aneurysms. Prophylactic obliteration during the acute stage of SAH may provide better outcomes if the unruptured dissecting lesion appears as obvious aneurysmal dilatation or pearl-and-string sign and is safely treatable with endovascular trapping.     

Clinical and anatomic outcomes after endovascular coiling of middle cerebral artery aneurysms: report on 30 treated aneurysms and review of the literature

BACKGROUND: Endovascular treatment of middle cerebral artery (MCA) aneurysms has not been extensively studied. We report our experience on a select group of patients that underwent coil embolization of an MCA bifurcation aneurysm. METHODS: From August 1999 to January 2005, 29 patients harboring 30 MCA aneurysms were treated with coil embolization. These patients were felt to have favorable characteristics for endovascular therapy including absence of thrombus in the aneurysm, absence of an efferent artery off of the aneurysm, and ability to reconstruct the wide neck with stent reconstruction. We retrospectively reviewed their records and angiographic images to evaluate for technical result and complications. RESULTS: The mean age of our cohort was 59 +/- 13 years with 19 patients presenting with a ruptured aneurysm. Complete obliteration was achieved in 24 (80%) of 30 of aneurysms on postprocedural angiography and no patient showed aneurysm regrowth at 6-month follow-up. Twenty-seven (93%) of 29 patients had no change in baseline neurological function post-embolization. There were two procedural-related complications: one intraprocedural rupture of an aneurysm and one thromboembolic stroke in the ipsilateral MCA territory. CONCLUSIONS: Coil embolization of MCA bifurcation aneurysms has a high rate of complete obliteration with acceptable morbidity in our selected group of patients.     

Multiple intracranial aneurysms and vascular abnormalities associated with neurofibromatosis type 1: a case report

We present an unusual case of multiple intracranial aneurysms, persistent primitive trigeminal artery (PPTA), and fenestration of the middle cerebral artery (MCA), associated with type 1 neurofibromatosis (NF 1). The patient was a 55-year-old woman in a state of semicoma. We observed widespread neurofibromas and café au lait spots on her trunk and limbs. Computed tomography (CT) scan revealed diffuse subarachnoid hemorrhage and right frontal intracerebral hemorrhage (WFNS grade IV, Fisher's classification group 4). Cerebral angiography showed two intracranial aneurysms at the anterior communicating artery, an aneurysm at the cavernous portion of the right carotid artery, a PPTA, and MCA fenestration. The patient remained in an apallic state, even after successful clipping of the anterior communicating artery aneurysms.     

M2/M2 side-to-side rescue anastomosis for accidental M2 trunk occlusion during middle cerebral artery aneurysm clipping: technical note

OBJECTIVE: A technically feasible and rapid technique for revascularizing the main branches of the middle cerebral artery (MCA) is described. This technique is applied mainly when clipping of an MCA aneurysm is complicated and occlusion of the origin of an MCA main branch results. METHODS: M2/M2 side-to-side anastomosis was applied in two patients in whom unplanned M2 occlusion occurred during the course of complicated MCA aneurysm clipping. The first patient underwent an emergency procedure after temporoparietal intracerebral hemorrhage. Unilateral mydriasis precluded preoperative angiographic workup, and a complex large MCA aneurysm was found as the source of hemorrhage. Shaping of the aneurysm neck by bipolar coagulation and clipping resulted in accidental occlusion of the superior trunk, and patency could not be regained despite multiple clip corrections. The second patient had an unruptured multilobulated aneurysm 8 mm in maximum diameter. Continuity of the inferior trunk was lost during clipping because of a tear at the origin. In both instances, side-to-side anastomosis was placed approximately 15 mm from the bifurcation, where the MCA main trunks ran side by side for a length of approximately 5 mm. RESULTS: After intracerebral hemorrhage, the first patient recovered to a level of moderate disability within 2 months. Substantial hemiparesis and expressive dysphasia remained as sequelae of the intracerebral hemorrhage. Digital subtraction angiography 2 months after the emergency procedure confirmed patency of the side-to-side anastomosis. The second patient was neurologically intact after recovery from anesthesia. Before discharge from the hospital on postoperative Day 8, digital subtraction angiography confirmed patency of the anastomosis. CONCLUSION: The MCA main branches usually run in close proximity for a short segment at the bottleneck entrance to the insular cistern. M2/M2 side-to-side anastomosis at this site is a rapid and feasible mode of revascularization of an M2 trunk accidentally occluded during complicated MCA aneurysm clipping.     

A middle cerebral artery dissecting aneurysm manifesting solely with pain, following a vertebral artery dissecting aneurysm

A 41-year-old male had presented with severe neck pain and was diagnosed as having a left vertebral artery (VA) dissecting aneurysm. During the observation period, he suddenly suffered from a pain on his left temple. MR imaging revealed neither SAH nor cerebral infarction. MR angiography, computed tomographic (CT) angiography and cerebral angiography showed fusiform dilatation of the M1 portion of the left middle cerebral artery (MCA) which had been normal in the former study. The abnormality of the left MCA normalized on both MR and CT angiography 6 months after the second onset. Because of the chronological change of radiological findings compatible with the symptom, we diagnosed the second episode as a MCA dissecting aneurysm manifesting with isolated pain. Among the previous forty-four MCA dissecting aneurysms, all but one case presented with hemorrhagic or ischemic event. In addition, this is the only case of multiple dissecting aneurysms of VA and MCA manifesting with isolated pain.     

Giant, fusiform and dissecting aneurysms at the vertebro-basilar junction--report of five cases and their clinical pathophysiological aspects

Five cases of giant, fusiform, and dissecting aneurysms of the vertebro-basilar junction, in which direct surgical treatment was not feasible, are reported. Their initial symptoms were as follows: 3 subarachnoid hemorrhages (2 fusiform aneurysms, 1 giant aneurysm), 1 mass sign (giant aneurysm), and 1 ischemic sign (dissecting aneurysm). In two patients, one with a giant and one with a dissecting aneurysm, preoperative proximal vertebral occlusion was carried out by inflated balloon for 30 to 100 minutes, under observation of clinical signs and measurement of distal arterial pressure. This catheter technique with an inflated balloon provides the means to assess the effect of vertebral artery occlusion in the alert patient, and to determine if occlusion is tolerated or not. In one case with a giant aneurysm, the proximal vertebral artery was occluded extracranially with no complications and no recurrent subarachnoid hemorrhage for 1 year. The other four patients (1 thrombosed giant aneurysm, 2 fusiform aneurysms, 1 dissecting aneurysm) whose contralateral vertebral arteries were hypoplastic, and who refused to operation, were treated conservatively for 6 months to 6 years. Their outcomes were better than expected, with no recurrent subarachnoid hemorrhage nor aggravation of clinical symptoms except for the one case with a dissecting aneurysm whose deterioration was presumed attributable to late cerebellar cortical atrophy.     

无蛛网膜下腔出血的大脑中动脉动脉瘤破裂

目的总结无蛛网膜下腔出血（SAH）的大脑中动脉（MCA）动脉瘤破裂的临床特点。方法对6例在首次CT扫描上表现为脑内出血（ICH），或壁内出血（IMH）而无SAH的MCA动脉瘤破裂患者的临床表现、影像学检查、治疗方法和预后进行回顾性总结。结果本组首次CT扫描时间为起病后0—2d，表现为单纯ICH者4例，IMH者2例。DSA和手术证实为MCA动脉瘤破裂。开颅动脉瘤切除1例，夹闭5例，其中4例同时行血肿清除术。术后无死亡。结论MCA动脉瘤破裂首次CT扫描可仅表现为ICH或IMH而无SAH，与动脉瘤的部位、出血量以及CT扫描时间相关。     

Surgical management of unruptured aneurysms: prognostic indicators

BACKGROUND: The treatment of unruptured aneurysms (UA) remains controversial. Therefore, it has become necessary to define various prognostic indicators in the surgical treatment of unruptured aneurysms not associated with previously ruptured aneurysms. METHODS: During a 6-year period, 78 unruptured aneurysms were managed. The results of management were retrospectively reviewed to define the prognostic indicators. RESULTS: There were 104 patients with unruptured aneurysms who underwent surgical treatment. Seventy-five patients without previous subarachnoid hemorrhage (SAH) were selected for data analysis. Eighty-seven percent of the aneurysms were on the anterior circulation. The most common location was the middle cerebral artery (MCA) followed by the posterior communicating artery (PCom), ophthalmic artery, and anterior communicating artery (ACom). Six percent were found on the basilar artery. The mean size of aneurysms was 12.5 mm (range = 3-30 mm, SD = 7.4). At surgery, rupture of the aneurysm was encountered in eight cases with temporary control of the parent vessel being required in 31 procedures. In four cases, intraoperative angiography warranted clip reapplication. The Glasgow Outcome Scale (GOS) was used as an outcome measure. Surgical treatment resulted in good outcome (GOS 1) in 87% and 10.7% had fair outcome; 2.3% were in GOS 3 (severe disability) at 6 month follow-up. There was no mortality. Logistic regression identified significant relationships between GOS and intraoperative rupture (p < 0.0002), rupture and size (p < 0.003), and size and age (p < 0.01). CONCLUSIONS: Large size aneurysms were associated with intraoperative rupture, which had a strong correlation with poor outcome. Increased age showed a linear relationship with the size of the aneurysm. Overall results of treatment for UA are gratifying. There was no mortality. Early diagnosis and surgical extirpation of UA may reduce both intraoperative difficulties as well as poor outcome probability.     

Long-term prognosis in patients with clipped unruptured cerebral aneurysms―increased cerebrovascular events in patients with surgically treated unruptured aneurysms

We retrospectively investigated surgical immediate and long-term overall results after clipping of the unruptured aneurysms. Between 1991 and 2008, 166 patients underwent neck clipping of unruptured saccular aneurysms at our institute. Patients were subsequently followed to clarify the occurrence of subarachnoid hemorrhage (SAH), and stroke other than SAH, aneurysm recurrence, cerebrovascular death, all-cause death, and risk factors. Surgical complication was noted in 14 patients (8.4 %) and surgical morbidity in two patients (1.2 %). Of 164 patients except for these two patients who suffered surgical morbidity, we could obtain more than 3 years follow-up information for 144 patients (87.8 %). There were 49 men and 95 women. The mean age was 58.5 years, and mean follow-up period was 7.9 years. Eight cases had died during follow-up (hepatic insufficiency in one, renal insufficiency in one, suicide in one, intracerebral hemorrhage (ICH) in two, SAH in one, and pneumonia after stroke in two). Therefore, the cause of death was stroke and late effects of stroke. Twelve symptomatic cerebrovascular events (cerebral infarction in seven, ICH in four, and SAH in one) occurred in ten patients. Consequently, annual risk of SAH after clipping of unruptured aneurysms was 0.085 %. Besides, annual risk of stroke in those patients was 1.06 %, and this incidence was higher than that in the general population. Although this study confirmed the good surgical result, annual risk of stroke after clipping of unruptured aneurysms was much higher than that in the general population. The long-term periodic examination to detect recurrent aneurysms and appropriate management to prevent stroke should be performed for patients with surgically treated unruptured aneurysm.     

Usefulness of CT angiography for demonstrating cerebral aneurysms

We report the usefulness of computed cerebral angiotomography (CT angiography) for demonstrating cerebral aneurysm and the clinical significance of CT angiography for ruptured cerebral aneurysm. Our modified method of CT angiography was easy and less time-consuming. Fifteen seconds after starting a single bolus injection, 1 ml/kg/25 seconds via cubital vein, of contrast medium (60% urograffin), 5 serial 5 mm thick-CT slices were scanned in every 6.5 seconds including 2 seconds of interval, beginning from an axial level 20 mm above the orbitomeatal line and ending at a level 40 mm. A total of 103 patients were examined in this report, consisting of 70 unruptured asymptomatic, 8 unruptured symptomatic (oculomotor nerve palsy) and 25 subarachnoid hemorrhage (SAH). Seven unruptured aneurysms in 4 asymptomatic cases, 2 unruptured aneurysms in 2 symptomatic cases 27 aneurysms in 24 SAH cases were suspected by CT angiography. Of these 36 aneurysms suspected by CT angiography 32 aneurysms were confirmed by cerebral angiography. The detection rate of CT angiography in this report was 89%, higher than those of previous reports. Thirteen aneurysms were located at internal carotid-posterior communicating artery (ICPC) junction. 11 at anterior communicating artery (Acom), 7 at middle cerebral artery (MCA). CT angiography showed a false positive findings in 4 cases, which were all located at Acom. Four aneurysms were not detected in CT angiography, which were all located at MCA and were very small (2-3 mm) in diameter. There were no deteriorated cases during and after CT angiography. We suggest that CT angiography is a useful and safe method for predicting the location of not only unruptured but ruptured aneurysms.     

A case of aneurysm of the peripheral middle cerebral artery undetectable on preoperative angiogram]

The authors describe a rare case of an aneurysm of the peripheral middle cerebral artery. A 63-year-old female with a past history of hypertension suddenly fell into a comatose state, and was brought to our hospital. On admission, CT scan showed intracerebral hematoma located in the right putamen with diffuse subarachnoid hemorrhage. To exclude vascular lesions, an angiography was performed just after admission. The right carotid angiogram showed an aneurysm at the cavernous portion of the internal carotid artery (ICA), but failed to show any aneurysms in the rest of the intracranial circulation. Just after the angiography, emergent operation was performed for the main purpose of evacuation of the hematoma, and with only the secondary purpose of searching for undetectable aneurysms. The patient underwent a right frontotemporal craniotomy. After partial evacuation of the hematoma through the corticotomy of the right frontal operculum, the Sylvian fissure was opened widely. No aneurysm was observed either in the main trunk of the right ICA or the middle cerebral artery (MCA). During the final stage of evacuation of the hematoma through the corticotomy, arterial bleeding occurred. While evacuating the blood, we detected a saccular aneurysm arising from MCA branch (M2-M3 junction) and we clipped the aneurysm. We discuss peripheral MCA aneurysms with a review of the literature.     

Endovascular coil placement compared with surgical clipping for the treatment of unruptured middle cerebral artery aneurysms: a consecutive series.

OBJECT: The goal of this study was to delineate the angioanatomical features that determine whether a patient with an unruptured middle cerebral artery (MCA) aneurysm is treated using endovascular coil placement or surgical clipping. METHODS: Thirty consecutive patients harboring 34 unruptured MCA aneurysms were evaluated. Patients with unruptured aneurysms are managed prospectively according to the following protocol: the primary treatment recommendation is endovascular packing with Guglielmi detachable coils (GDCs). Surgical clipping is recommended after failed attempts at coil placement or in the presence of angioanatomical features that contraindicate that type of endovascular therapy. Of 34 unruptured MCA aneurysms, two (6%) were successfully embolized and 32 (94%) were clipped. Of these 32 surgically treated aneurysms, in 11 (34%) an attempt at GDC embolization had failed, whereas in 21 (66%) primary clipping was performed because of unfavorable angioanatomy. Of the 13 aneurysms treated endovascularly, two (15%) were successfully excluded, whereas GDC treatment failed in 11 (85%). An unfavorable dome/neck ratio (< 2) and an arterial branch originating at the aneurysm base were the reasons for embolization failure. CONCLUSIONS: Careful evaluation of the angioanatomy of unruptured aneurysms allows selection of the most appropriate treatment. However, for unruptured MCA aneurysms, surgical clipping appears to be the most efficient treatment option. Series of unruptured aneurysms are ideal for comparing treatment results.     

Far lateral suboccipital approach for the treatment of proximal posteroinferior cerebellar artery aneurysms: surgical results and long-term outcome

OBJECTIVE: Proximal posteroinferior cerebellar artery (PICA) aneurysms are challenging to treat surgically, with high reported perioperative complication rates. We describe the perioperative course and long-term clinical outcomes obtained via a far lateral suboccipital approach in 20 consecutive proximal PICA aneurysms. METHODS: Data were collected prospectively on the first 20 proximal PICA aneurysms treated surgically by a single surgeon (ESC) between December 1997 and April 2003. All aneurysms were clipped via a far lateral approach. Patients with unruptured aneurysms were assessed at 3 and 12 months after surgery. For all subarachnoid hemorrhage patients, a battery of outcome tests was performed at 3- and 12-month intervals. Outcomes were then compared with those of a contemporaneously managed population of ruptured right-sided posterior communicating artery aneurysms. RESULTS: The far lateral suboccipital approach achieved adequate exposure in all cases. There were no intraoperative complications or intraoperative aneurysm ruptures. All patients with unruptured aneurysms were fully functional at long-term follow-up. At 3 months of follow-up, 93% of the subarachnoid hemorrhage patients achieved a Glasgow Outcome Scale score of 1 to 2. At 12 months of follow-up, 92% achieved a Glasgow Outcome Scale score of 1 to 2. Compared with the patients with a ruptured right-sided posterior communicating artery aneurysm, no difference could be found in quality of life or activities of daily living at either time point. CONCLUSION: The favorable outcomes and low postoperative morbidity in this subset of patients argues that clipping via this approach be considered a first-line therapeutic option. When performed in this manner, PICA aneurysm surgery seems to have no greater morbidity than right-sided posterior communicating artery aneurysm surgery.     

Dissecting aneurysms of the bilateral vertebral arteries with subarachnoid hemorrhage: report of three cases

OBJECTIVE AND IMPORTANCE: Treatment of one side in cases of dissecting aneurysms of the bilateral vertebral arteries (VAs) with subarachnoid hemorrhage may result in dissection or rupture on the contralateral side. CLINICAL PRESENTATION: Three patients presented with dissecting aneurysms of the bilateral VAs with subarachnoid hemorrhage. INTERVENTION: Two patients underwent trapping of the ruptured VA, with side-to-side anastomosis between the bilateral posteroinferior cerebellar arteries. One patient underwent resection of the ruptured VA, with interposition of a saphenous vein graft. Two patients died as a result of rupture of the contralateral VA dissecting aneurysm after surgery. One patient demonstrated development of an unruptured dissecting aneurysm in the contralateral VA 1 month after surgery. CONCLUSION: Surgical intervention to treat dissecting aneurysms of the bilateral VAs on one side carries the risk of rupture of the contralateral lesion. Increased hemodynamic stress may be important in the development and rupture of dissections in the contralateral VA.