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Objective: Stent-assisted coil embolization for the treatment of intracranial aneurysms has been used widely. This study aimed to investigate the effect of stent implantation in the nonatherosclerotic parent artery with cerebral aneurysms. The authors evaluated luminal changes and the related factors following stent-assisted coil embolization., Methods: This study included 97 patients harboring a total of 99 unruptured aneurysms of the distal internal carotid artery (ICA) who underwent single-stent implantation and more than 1 session of conventional angiography during follow-up (midterm follow-up only, n = 70; midterm and long-term follow-up, n = 29) between January 2009 and April 2014. The luminal narrowing point was measured using a local thickness map (ImageJ plug-in)., Results: Stent-assisted coil embolization caused dynamic luminal narrowing of approximately 82% of the parent artery diameter on average after 8 months, which was reversed to 91% after 25 months. In addition, luminal narrowing greater than 40% was noticed in 2 (7%) of the 29 patients who experienced spontaneous reversion without additional management during follow-up. Most luminal narrowing changes seen were diffuse., Conclusions: Luminal narrowing after aneurysm stent-assisted coil embolization is a dynamic process and appears to be a spontaneously reversible event. Routine management of luminal narrowing may not cause adverse events that require additional treatment.

Object: Recent studies have demonstrated that plaque morphology can contribute to identification of patients at high risk of carotid artery atherosclerosis as well as the degree of stenosis in those with carotid atherosclerosis. Neovascularization of carotid plaques is associated with plaque vulnerability. However, the mechanism of neovascularization in intraplaque hemorrhage (IPH) and its clinical contribution remain undetermined. In this study, the authors aimed to clarify the characteristics of neovessel appearance with a focus on inwardly projecting neovessels, which are reportedly important in plaque advancement., Methods: Consecutive patients with moderate to severe carotid atherosclerosis who underwent carotid endarterectomy were prospectively analyzed from 2010 to 2014. The neovessel appearance was categorized into 3 groups based on intraoperative indocyanine green (ICG) videoangiography: early appearance of neovessels from the endothelium (NVe), late appearance of neovessels from the vasa vasorum (NVv), and no appearance of vessels. Each neovessel pattern was evaluated with respect to clinical, radiological, and pathological findings including IPH, neovascularization, hemosiderin spots, and inflammation., Results: Of 57 patients, 13 exhibited NVe, 33 exhibited NVv, and 11 exhibited no neovessels. Overall, the interobserver and intraobserver reproducibilities of neovessel appearance were substantial for ICG videoangiography (κ=0.76) and at 7 days postoperatively (κ=0.76). There were no significant differences in baseline characteristics among the 3 groups, with the exception of a higher percentage of symptomatic presentations in patients with NVe (artery-to-artery embolic infarction in 61.5% and transient ischemic attack in 23.1%). Moreover, patients with NVe exhibited larger infarctions than did those with NVv (9675.0±5601.9 mm3 vs 2306.6±856.9 mm3, respectively; p=0.04). Pathologically, patients with NVe had more severe IPH (47.2±8.3 mm2 vs 19.8±5.2 mm2, respectively; p<0.01), hemosiderin spots (0.5±0.2 mm2 vs 0.2±0.1 mm2, respectively; p=0.04), neovessels (0.4±0.7 mm2 vs 0.1±0.4 mm2, respectively; p=0.11), and inflammation (1.0±1.1 mm2 vs 0.6±0.9 mm2, respectively; p=0.26) around the endothelium than did patients with NVv, and all of these parameters were correlated with hyperintensity on time-of-flight MRI. However, the neovessel and inflammation differences were nonsignificant. Interestingly, inflammation was significantly correlated with neovessel formation (r=0.43, p=0.0008), hemosiderin spots (r=0.62, p<0.0001), and IPH (r=0.349, p=0.0097), suggesting that inflammation may be a key factor in plaque vulnerability., Conclusions: Communication of inwardly projecting neovessels with the lumen and inflammation synergistically contribute to IPH and symptomatic presentations in patients with carotid stenosis and are more specific than the vasa vasorum. This condition could be a new therapeutic target, and regression of luminal neovessel sprouting and inflammation may help to prevent IPH development and a symptomatic presentation.

Object: Surgery for aneurysms at the anterior wall of the internal carotid artery (ICA), which are also referred to as ICA anterior wall aneurysms, is often challenging. A treatment strategy needs to be determined according to the pathology of the aneurysm-namely, whether the aneurysm is a saccular aneurysm with firm neck walls that would tolerate clipping or coiling, a dissecting aneurysm, or a blood blister-like aneurysm. However, it is not always possible to properly evaluate the condition of the aneurysm before surgery solely based on angiographic findings., Methods: The authors focused on the location of the ophthalmic artery (OA) in determining the pathology of ICA anterior wall aneurysms. Between January 2006 and December 2012, diagnostic cerebral angiography, for any reason, was performed on 1643 ICAs in 855 patients at Saitama Medical Center. The authors also investigated the relationship between the origin of the OA and the incidence of ICA anterior wall aneurysms. The pathogenesis was also evaluated for each aneurysm based on findings from both angiography and open surgery to identify any correlation between the location where the OA originated and the conditions of the aneurysm walls., Results: Among 1643 ICAs, 31 arteries (1.89%) were accompanied by an anomalous origin of the OA, including 26 OAs originating from the C3 portion, 3 originating from the C4 portion, and 2 originating from the anterior cerebral artery. The incidence of an anomalous origin of the OA had no relationship to age, sex, or side. Internal carotid artery anterior wall aneurysms were observed in 16 (0.97%) of 1643 ICAs. Female patients had a significantly higher risk of having ICA anterior wall aneurysms (p = 0.026). The risk of ICA anterior wall aneurysm formation was approximately 50 times higher in patients with an anomalous origin of the OA (25.8% [8 of 31]) than in those with a normal OA (0.5% [8 of 1612], p < 0.0001). Based on angiographic classifications, saccular aneurysms were significantly more common in patients with an anomalous origin of the OA than in those with a normal OA (p = 0.041). Ten of 16 patients with ICA anterior wall aneurysms underwent craniotomies. Based on the intraoperative findings, all 6 aneurysms with normal OAs were dissecting or blood blister-like aneurysms, not saccular aneurysms., Conclusions: There was a close relationship between the location of the OA origin and the predisposition to ICA anterior wall aneurysms. Developmental failure of the OA and subsequent weakness of the vessel wall might account for this phenomenon, as previously reported regarding other aneurysms related to the anomalous development of parent arteries. The data also appear to indicate that ICA anterior wall aneurysms in patients with an anomalous origin of the OA tend to be saccular aneurysms with normal neck walls. These findings provide critical information in determining therapeutic strategies for ICA anterior wall aneurysms.

Object: A small percentage of cerebral aneurysms rupture, but when they do, the effects are devastating. Current management of unruptured aneurysms consists of surgery, endovascular treatment, or watchful waiting. If the biology of how aneurysms grow and rupture were better known, a novel drug could be developed to prevent unruptured aneurysms from rupturing. Ruptured cerebral aneurysms are characterized by inflammation-mediated wall remodeling. The authors studied the role of stromal cell-derived factor-1 (SDF-1) in inflammation-mediated wall remodeling in cerebral aneurysms., Methods: Human aneurysms, murine carotid artery aneurysms, and murine intracranial aneurysms were studied using immunohistochemistry. Flow cytometry analysis was performed on blood from mice developing carotid or intracranial aneurysms. The effect of SDF-1 on endothelial cells and macrophages was studied by chemotaxis cell migration assay and capillary tube formation assay. Anti-SDF-1 blocking antibody was given to mice and compared with control (vehicle)-administered mice for its effects on the walls of carotid aneurysms and the development of intracranial aneurysms., Results: Human aneurysms, murine carotid aneurysms, and murine intracranial aneurysms all expressed SDF-1, and mice with developing carotid or intracranial aneurysms had increased progenitor cells expressing CXCR4, the receptor for SDF-1 (p < 0.01 and p < 0.001, respectively). Human aneurysms and murine carotid aneurysms had endothelial cells, macrophages, and capillaries in the walls of the aneurysms, and the presence of capillaries in the walls of human aneurysms was associated with the presence of macrophages (p = 0.01). Stromal cell-derived factor-1 promoted endothelial cell and macrophage migration (p < 0.01 for each), and promoted capillary tube formation (p < 0.001). When mice were given anti-SDF-1 blocking antibody, there was a significant reduction in endothelial cells (p < 0.05), capillaries (p < 0.05), and cell proliferation (p < 0.05) in the aneurysm wall. Mice given anti-SDF-1 blocking antibody developed significantly fewer intracranial aneurysms (33% vs 89% in mice given control immunoglobulin G, respectively; p < 0.05)., Conclusions: These data suggest SDF-1 is associated with angiogenesis and inflammatory cell migration and proliferation in the walls of aneurysms, and may have a role in the development of intracranial aneurysms.

Object: Over the past 20 years, endovascular embolization has become the preferred method of treating cerebral aneurysms. While there are many embolic devices on the market, none is ideal. In this study the authors investigated the use of a liquid-to-solid gelling polymer system-that is, poly(propylene glycol) diacrylate and pentaerythritol tetrakis (3-mercaptopropionate) (PPODA-QT)-to embolize in vivo aneurysms over a 6-month period., Methods: Experimental aneurysms were created in the carotid arteries of 9 canines. Aneurysms were embolized with the polymer only (PPODA-QT, 3 dogs), filled with PPODA-QT after placement of a "framing" platinum coil (coil+PPODA-QT, 3 dogs), or packed with platinum coils (coils only, 3 dogs). Aneurysm occlusion was angiographically monitored immediately and 6 months after embolization. After 6 months, the ostial regions of explanted aneurysms were assessed macroscopically and histologically., Results: All aneurysms showed 100% angiographic occlusion at 6 months, but turbulent blood flow was observed in 1 coils-only sample. Ostial regions of explanted coils-only aneurysms showed neointimal tissue surrounding individual coils but no continuous tissue layer over the aneurysm neck. All PPODA-QT aneurysms displayed smooth ostial surfaces, but 2 of 3 coil+PPODA-QT aneurysms showed polymer (unassociated with the coil) protruding into the vessel lumen, contributing to rough ostial surfaces. Neointimal tissue was present in PPODA-QT and coil+PPODA-QT aneurysms and covered smooth ostial surfaces more completely than in coils-only aneurysms., Conclusions: This study compared neointimal tissue overgrowth in the ostium of experimental aneurysms embolized with PPODA-QT, PPODA-QT plus a framing coil, or coils alone. The coils-only and coil+PPODA-QT groups showed rough and discontinuous ostial surfaces, which hindered neointimal tissue coverage. The PPODA-QT aneurysms consistently produced smooth ostial surfaces that facilitated more complete neointimal tissue coverage over aneurysm necks.

Object: Fragile aneurysm walls and poorly defined necks render the surgical treatment of blood blister–like aneurysms (BBAs) located at nonbranching sites of the supraclinoid internal carotid artery extremely challenging. Such aneurysms have a remarkable tendency to rupture during surgery, especially during the acute period. The authors describe the clinical course of patients with subarachnoid hemorrhage (SAH) caused by BBA rupture and emphasize the value of internal carotid artery trapping combined with high-flow extracranial-intracranial (trapping/EC-IC) bypass during the acute period following SAH., Methods: The authors analyzed the clinical records of 7 consecutive female patients with a mean age of 61 years (range 51–77 years) who had been treated between January 2006 and December 2008 at their institute., Results: All 7 patients presented with SAHs corresponding to Fisher Grade 3 and World Federation of Neurosurgical Societies Grades II, III, IV, and V in 3, 1, 2, and 1 patient, respectively. Surgery was postponed in the 3 patients, including 1 in whom the trapping/EC-IC bypass procedure was performed during the chronic period. Two of the 3 patients in whom surgery was postponed experienced preoperative rebleeding, and repeated angiography revealed remarkable enlargement of the aneurysm; both of these patients died before surgery could be performed. The remaining 4 patients underwent trapping/EC-IC bypass during the acute period following SAH. The outcome was excellent (Glasgow Outcome Scale Scores 5), and postoperative angiography demonstrated complete obliteration of the BBA as well as good graft patency in all 5 patients who underwent trapping/EC-IC bypass. Intraoperative bleeding from the BBAs never occurred in any of these 5 patients., Conclusions: Ruptured BBAs were successfully treated with a trapping/EC-IC bypass during the acute SAH period. This surgical strategy for treating BBAs during the acute period might be a promising option for these rare but high-risk lesions.

The authors report a rare case of slowly progressive neuronal death associated with postischemic hyperperfusion in cortical laminar necrosis after radial artery/external carotid artery-middle cerebral artery bypass graft surgery for an intracavernous carotid artery aneurysm. Under barbiturate protection, a 69-year-old man underwent high-flow bypass surgery combined with carotid artery sacrifice for a symptomatic intracavernous aneurysm. The patient became restless postoperatively, and this restlessness peaked on postoperative Day (POD) 7. Diffusion-weighted and FLAIR MR images obtained on PODs 1 and 7 revealed subtle cortical hyperintensity in the temporal cortex subjected to temporary occlusion. On POD 13, (123)I-iomazenil ((123)I-IMZ) SPECT clearly showed increased distribution on the early image and mildly decreased binding on the delayed image with count ratios of the affected-unaffected corresponding regions of interest of 1.23 and 0.84, respectively, suggesting postischemic hyperperfusion. This was consistent with the finding on (123)I-iodoamphetamine SPECT. Of note, neuronal density in the affected cortex on the delayed (123)I-IMZ image further decreased to the affected/unaffected ratio of 0.44 on POD 55 during the subacute stage when characteristic cortical hyperintensity on T1-weighted MR imaging, typical of cortical laminar necrosis, was emerging. The affected cortex showed marked atrophy 8 months after the operation despite complete neurological recovery. This report illustrates, for the first time, dynamic neuroradiological correlations between slowly progressive neuronal death shown by (123)I-IMZ SPECT and cortical laminar necrosis on MR imaging in human stroke.

Object: Treatment of cerebral aneurysms by endovascular deployment of liquid embolic agents has been proposed as an alternative strategy to conventional coiling, and new materials are being developed for embolization. In this study, the authors used a single-injection, biocompatible, biodegradable and pH-responsive acrylated chitosan (aCHN) with conjugated vascular endothelial growth factor (rhVEGF) in a rat aneurysm model., Methods: The efficacy of the aCHN formulation with rhVEGF was tested using a common carotid artery occlusion model in rats, and the extent of embolization was evaluated using quantitative, qualitative, and histopathological techniques after 14 days of implantation., Results: The mean occlusion was significantly greater for the rhVEGF/aCHN-treated group (96.8 +/- 3.0%) than for the group receiving aCHN (74.7 +/- 5.6%) (p < 0.01). Through qualitative evaluation, intimal and medial proliferation were significantly greater with rhVEGF/aCHN than with aCHN and controls (p < 0.001). Degradation of the aCHN filler was monitored in concert with the production of extracellular matrix components. Macrophages migrated in and proliferated inside the occluded carotid artery lumens were identified by histological and immunostainings. Results showed resorption of chitosan with concurrent development of collagen and elastin into the vessel lumen, suggesting clot maturation into fibrosis., Conclusions: Chitosan with a bioactive agent such as rhVEGF showed excellent results in occluding aneurysms in a rat model.

Object: The efficacy and pitfalls of endovascular recanalization were evaluated in cases of internal carotid artery (ICA) occlusion in the subacute to chronic stage., Methods: Fourteen cases (15 lesions) of symptomatic ICA occlusion with hemodynamic compromise or recurrent symptoms were treated at the subacute to chronic stage using an endovascular technique. The Parodi embolic protection system was used during the recanalization procedure to prevent embolic stroke by reversing the flow from the distal ICA to the common carotid artery., Results: Recanalization of the occluded ICA was possible in 14 of 15 lesions. The occlusion points were 10 cervical ICAs and 4 petrous/cavernous ICAs in successfully recanalized cases. Ischemic symptoms disappeared completely after the treatment, and new ischemic symptoms did not appear related to the treated lesion. Single photon emission computed tomography findings demonstrated the improvement of hemodynamic compromise in all cases. One case showed right middle cerebral artery branch occlusion during the procedure, but this patient's neurological symptoms were stable due to preexisting hemiparesis. Endovascular recanalization was possible and effective in improving hemodynamic compromise. However, there are still several problems with this technique, such as hyperperfusion syndrome after recanalization, cerebral embolism during treatment, durability after treatment, and identification of the occlusion point before treatment., Conclusions: Endovascular recanalization using an embolic protection device can be considered as an alternative treatment for symptomatic ICA occlusion with hemodynamic compromise or refractoriness to antiplatelet therapy, even in the subacute to chronic stage of the illness.

Object: The goal of this study was to evaluate the usefulness of long-axis black-blood MR (BB-MR) imaging for assessing plaque morphology and distribution in patients with atherosclerotic carotid artery (CA) stenosis., Methods: Sixty-eight carotid arteries in 67 patients who were scheduled to undergo CA endarterectomy or CA stent placement due to atherosclerotic stenosis were included in this study. The patients had undergone CA BB-MR imaging and digital subtraction (DS) angiography within 3 weeks of revascularization. The DS angiography studies were performed using the transfemoral artery approach with selective common CA catheterization. The BB-MR images were acquired using a 1.5-T whole-body MR imaging unit, and T1-weighted images parallel to the long axis of the artery at 1-mm intervals were obtained. Plaque distribution was evaluated by measuring the distance between the CA bifurcation and the point that appeared to be the distal extent of the plaque on BB-MR imaging (D-MR imaging) and DS angiography images (D-DS angiography)., Results: Plaque distribution was clearly shown in 88.2% of the cases using long-axis BB-MR images, except for 8 arteries with poor image quality. In 4 arteries, D-DS angiography could not be obtained because the distal plaque end could not be confirmed. In 56 vessels, both the D-DS angiography and D-MR imaging could be measured; the mean D-MR imaging (19.75 +/- 6.85 mm [standard deviation]) was significantly longer than the average D-DS angiography (16.32 +/- 7.07 mm)., Conclusions: Long-axis BB-MR imaging can provide a noninvasive and accurate way to show CA plaque distribution; it is of great use not only for stroke risk assessment in patients with CA atherosclerosis but also for preoperative evaluation in patients requiring CA endarterectomy or CA stent placement.

Object: Plaque hemorrhage in carotid atherosclerosis promotes plaque progression, resulting in cerebrovascular disease. Hypoxia inducible factor-1alpha (HIF-1alpha) induces angiogenesis via the expression of vascular endothelial growth factor (VEGF) and E26 transformation-specific-1 (Ets-1). The authors investigated human carotid plaques to determine whether these hypoxia-inducible angiogenic proteins play a major role in intraplaque angiogenesis and hemorrhage., Methods: The expression of HIF-1alpha, VEGF, and Ets-1 was analyzed using immunohistochemistry and Western blotting in 29 human carotid plaques obtained at carotid endarterectomy. The authors investigated the relationship between plaque characteristics and clinical symptoms., Results: A higher incidence of plaque hemorrhage was observed in plaques associated with symptoms than in those without symptoms (p = 0.03). Hypoxia-inducible factor-1alpha, VEGF, and Ets-1 coexisted in the deep layer of plaque, where angiogenesis was remarkably developed; the expression levels of HIF-1alpha, VEGF, and Ets-1 were significantly enhanced in the main lesion of the plaque (p < 0.01). Symptomatic plaques showed higher expression of VEGF (p = 0.04) than asymptomatic plaques. Plaques with hemorrhage showed a higher incidence of plaque ulcer (p = 0.001) and higher expression of Ets-1 (p = 0.03) than those without hemorrhage. Moreover, significantly increased expressions of VEGF (p = 0.01) and Ets-1 (p = 0.006) were observed in plaques with not only hemorrhages but also ulcers and severe stenosis., Conclusions: The findings in this study suggest that hypoxia-inducible angiogenic proteins in human carotid atherosclerosis promote intraplaque angiogenesis, which can induce plaque hemorrhage and progression.

Object: Because of the anatomical complexity of the paraclinoid region, the surgical treatment of aneurysms arising in the C(6) segment of the internal carotid artery is extremely challenging. The authors' aim in this study was to describe the extended clinical follow-up and assess the short-term and long-term effectiveness of surgical treatment for these aneurysms, focusing on the clinical outcome and degree of aneurysm occlusion and recurrence., Methods: The authors retrospectively analyzed the clinical records for patients treated surgically between 1973 and 2004 at the University of Rome, "La Sapienza." Aneurysms were classified into the following 3 groups according to the site where they arose: the anteromedial, anterior or anterolateral, and posteromedial wall of the C(6) segment., Results: Of the 108 aneurysms in 104 patients treated, 63 (58%) were large or giant. Eighty-eight aneurysms in 84 patients were clipped, 16 underwent a high-flow bypass, 2 were trapped, 1 was wrapped, and 1 was left untreated. The mean follow-up was 126 months; 47 patients had a follow-up of > 10 years. Of the 88 aneurysms that were clipped, 6 (6.8%) had an incomplete occlusion that required an immediate reoperation in 1 case and at 2 years in another. Overall 6 patients (5.8%) had surgery-related permanent complications., Conclusions: Mortality and morbidity rates depend mainly on the patient's preoperative Hunt and Hess grade subarachnoid hemorrhage, whereas surgical morbidity principally reflects excessive manipulation of the optic nerve or ischemic problems due to excessive temporary trapping undertaken without adequate neuroprotection. In expert hands, surgery (clipping and bypass procedures) is a definitive treatment for C(6) aneurysms and has an acceptable complication rate.

The authors report a case in which a 62-year-old woman with a history of subarachnoid hemorrhage due to a ruptured aneurysm was found to have a de novo paraclinoid aneurysm in the right internal carotid artery during a routine medical examination. Surgical clip placement was performed via a contralateral pterional approach under visual evoked potential (VEP) monitoring. The superior hypophyseal artery (SHA) was found to originate from the aneurysm body. The artery was temporarily occluded prior to application of the clip to the aneurysm neck. The VEP signal was lost 3 minutes after the SHA was occluded, and the potentials gradually recovered 10 minutes after the artery was released. The disappearance of VEP signal was reproducible with SHA occlusion. The clip was applied to the aneurysm body to preserve the origin of the SHA. The patient did not have any deterioration of vision after surgery. Intraoperative VEP monitoring can be used to help determine whether the SHA can be sacrificed safely.

Object: Aneurysmal subarachnoid hemorrhage affects approximately 10/100,000 people per year. Endovascular coil embolization is used increasingly to treat cerebral aneurysms and its safety and durability is rapidly developing. The long-term durability of coil embolization of cerebral aneurysms remains in question; patients treated using this modality require multiple follow-up angiography studies and occasional repeated treatments., Methods: Optical coherence tomography (OCT) is an emerging imaging modality that uses backscattered light to produce high-resolution tomography of optically accessible biological tissues such as the eye, luminal surface of blood vessels, and gastrointestinal tract. Vascular OCT probes in the form of imaging microwires are presently available--although not Food and Drug Administration-approved--and may be adapted for use in the cerebral circulation. In this study the authors describe the initial use of OCT to make visible the neck of aneurysms created in a canine model and treated with coil embolization. Optical coherence tomography images demonstrate changes that correlate with the histological findings of healing at the aneurysm neck and thus may be capable of demonstrating human cerebral aneurysm healing., Conclusions: Optical coherence tomography may obviate the need for subsequent follow-up angiography studies as well as aid in the understanding of endovascular tissue healing. Data in this study demonstrate that further investigation of in vivo imaging with such probes is warranted.

The authors present the case of a 50-year-old woman with a history of CREST syndrome (calcinosis, Raynaud phenomenon, esophageal motility disorders, sclerodactyly, and telangiectasia), a variant of scleroderma, who was incidentally found to have an irregular intracranial aneurysm. The patient presented with migraine headaches. A magnetic resonance image of the brain obtained during the headache workup revealed a right posterior carotid artery wall aneurysm in the region of the anterior choroidal artery (AChA). On digital subtraction angiograms, the lesion measured 3.5 mm at its largest diameter. Because of the irregular shape of the aneurysm, the patient's relatively young age, and the potential for further aneurysm growth due to collagen disease, surgical clip application was recommended following a discussion of available treatment options. At surgery, the aneurysm was identified as bilobed and broad based, and the AChA was found to be associated with the aneurysm neck. Satisfactory clipping of the aneurysm was achieved with preservation of the parent vessels. An association of CREST syndrome with intracranial aneurysms has only been reported once before. This case is presented to draw attention to the possibility of a pathophysiological connection between CREST syndrome and intracranial aneurysms and to postulate a possible mechanism whereby this condition may result in aneurysm formation. The association of aneurysms with other pathological collagen-related conditions is well known, and literature relevant to a possible connection between CREST syndrome and aneurysms is reviewed and discussed.

Giant serpentine aneurysms (GSAs) are defined as partially thrombosed giant aneurysms with persistent serpentine vascular channels. Surgical management of these rare lesions is difficult because of their large size, complex structure, and unique hemodynamics. The authors report two cases of patients harboring GSAs with mass effect, which were managed effectively with endovascular treatment. The first patient was a 48-year-old man who presented with left homonymous hemianopsia caused by a GSA involving the terminal portion of the right internal carotid artery. The second patient, a 10-year-old boy, presented with tetraparesis from compression of the cervicomedullary junction by a GSA of the right vertebral artery. In each case, after confirming collateral flow by temporarily occluding the proximal artery, the aneurysm was trapped by placement of Guglielmi detachable coils at the sites at which the serpentine channels entered and exited the aneurysm. The midportion of each channel was isolated completely without packing, to maximize resorption of the devascularized mass. Mass effect and clinical symptoms rapidly improved in both cases, with no associated morbidity. We recommend endovascular trapping as a safe and effective therapeutic option for GSAs.

Petrous and cavernous sinus carotid artery (CA) aneurysms that are not amenable to clip ligation or endovascular therapy may be successfully treated by a saphenous vein bypass, thereby preserving the patency of the CA. The authors report the unique case of a 47-year-old man with a giant fusiform aneurysm of the petrous CA, who presented with a rapid onset of a lateral rectus palsy and diplopia. The lesion was treated by trapping the aneurysm and performing a saphenous vein bypass from the cervical to the intracranial CA. The saphenous vein graft was routed beneath the condyle of the mandible to reduce the overall length of the graft, thereby increasing the likelihood of long-term patency and offering protection to the graft by the mandible, temporal muscle zygomatic process, and masseter and temporal muscles. The presentation and technical aspects of the bypass graft in this unique case are discussed.

The authors describe the histopathological findings in a case involving rerupture of a recanalized aneurysm of the internal carotid artery 8 months after partial (95%) embolization with interlocking detachable coils. The aneurysm was filled with poorly organized thrombus, and its orifice was devoid of endothelial cells. It appears likely that a long period of observation may be required to confirm the complete thrombotic organization of coil-embolized aneurysms. This indicates that caution is needed because rupture may follow recanalization of the aneurysm.

Despite advances in the surgical treatment of meningiomas located at the skull base, surgery for meningiomas involving the cavernous sinus remains controversial. The controversy centers on whether complete resection of such a meningioma is possible while preserving cranial nerve function. To evaluate this question, the authors examined six patients with benign meningiomas involving the cavernous sinus. The pathological features of these tumors were evaluated and compared with the normal histoarchitecture of the cavernous sinus. The tendency of these tumors to be infiltrative is evident and this seems to occur along connective tissue planes within the cavernous sinus. This invasiveness can be explained by the peculiar structure of this region. The trigeminal nerve and ganglion seem to be particularly prone to invasion; this does not correlate with the degree of preoperative impairment of nerve function. Internal carotid artery invasion occurs frequently and can be seen even when there is no narrowing of the artery on arteriography. The pituitary gland can also be invaded by the tumor, which penetrates the thin dural barrier.

Intracranial meningiomas are known to infiltrate surrounding structures such as the calvaria and dural sinuses, and the brain itself. The issue of whether meningiomas invade major intracranial arteries is of clinical importance, particularly in the case of meningiomas of the cavernous sinus. If a meningioma has not invaded the carotid artery wall, complete tumor removal may be accomplished with careful dissection from the carotid artery; however, if the tumor has infiltrated the wall of the carotid artery, complete removal may require sacrifice of the artery. To determine whether cavernous sinus meningiomas invade the carotid artery, the authors retrospectively reviewed the histopathology of 19 consecutively treated individuals whose carotid artery was sacrificed during removal of a meningioma involving the cavernous sinus. Patients were selected for carotid artery resection based on preoperative magnetic resonance imaging studies demonstrating complete encasement of the artery. Reconstruction of the carotid artery was planned depending on the results of preoperative balloon test occlusion with blood flow determinations. None of the 19 patients had pathological evidence of malignant tumor. Eight individuals (42%) were found to have infiltration of the carotid artery by meningioma. In five cases, focal involvement of the adventitia of the carotid artery wall was noted and, in three, the vessel was infiltrated up to the tunica muscularis. In no case was the tunica muscularis invaded by tumor. Thus, meningiomas of the cavernous sinus do infiltrate the internal carotid artery and, in order to completely resect these lesions and effect a surgical cure, it may be necessary to sacrifice the carotid artery with or without reconstruction.

Laser energy at a wavelength of 480 nm was applied in 1-microseconds pulses of 3 to 10 mJ to two models of vasospasm. Rabbit common carotid arteries (CCA's) were constricted chronically by the application of human blood within a silicone sheath. Peak vasospasm developed 24 to 48 hours later, and persisted for up to 6 days. Endovascular laser treatment was delivered to 40 CCA's via a 200-microns diameter silica quartz fiber introduced through the femoral artery. The CCA caliber increased from 60% of the pre-vasospasm control diameter to a minimum post-laser diameter of 83% of control. No instances of laser-induced perforation or of arterial thrombosis were observed for up to 60 days after treatment. Prophylactic laser application to nine normal vessels was able to attenuate the development of vasospasm if blood was applied immediately thereafter (88% vs. 59% of control diameter, p less than 0.02), but not if blood was applied 7 days later. Studies in 16 normal CCA's established that there was a considerable margin between the laser energy required to induce dilatation and that which caused perforation, providing that the fiber remained relatively central within the artery. Morphological examination demonstrated focal loss of endothelial cells immediately after laser application, followed approximately 7 days later by the development of areas of intimal hyperplasia. Only minimal changes were observed in the medial or adventitial layers. In a second study, the basilar artery of seven dogs was constricted chronically by two intracisternal injections of autologous blood 3 days apart. Five dogs received endovascular laser treatment 7 or 10 days after the first injection, when basilar artery diameter was reduced to a mean of 61% and 77% of control, respectively. Immediately following treatment, basilar artery diameter increased to 104% and 102% of resting diameter, respectively. Both untreated and laser-treated arteries were smaller than the control diameter at 30 days (80% and 82%, respectively), but in each group the vasodilatory response to hypercapnia was preserved. These findings indicate that 1-microsecond laser pulses are well tolerated by systemic and cerebral arteries in two different animal models, and suggest that the 480-nm pulsed-dye laser may have an application for the treatment or prophylaxis of cerebral vasospasm.

Eleven experimental saccular aneurysms were created on the common carotid artery of swine. Between 3 and 15 days after creation of these aneurysms, they were thrombosed via an endovascular approach, using a very soft detachable platinum coil delivered through a microcatheter positioned within the aneurysm. This detachable platinum coil was soldered to a stainless steel delivery guidewire. Intra-aneurysmal thrombosis was then initiated by applying a low positive direct electric current to the delivery guidewire. Thrombosis occurred because of the attraction of negatively charged white blood cells, red blood cells, platelets, and fibrinogen to the positively charged platinum coil positioned within the aneurysm. The passage of electric current detached the platinum coil within the clotted aneurysm in 4 to 12 minutes. This detachment was elicited by electrolysis of the stainless steel wire nearest to the thrombus-covered platinum coil. Control angiograms obtained 2 to 6 months postembolization confirmed permanent aneurysm occlusion as well as patency of the parent artery in all cases. No angiographic manifestation of untoward distal embolization was noted. Due to the encouraging results of this research, this technique has been applied in selected clinical cases which are described in Part 2 of this study.

A mycotic aneurysm of the intracavernous portion of the carotid artery produced total ophthalmoplegia in a 2-year-old boy. Serial angiography displayed progressive enlargement of the aneurysm which was successfully treated by carotid ligation. Angiography is mandatory to role out carotid artery complications secondary to cavernous sinus thrombophlebitis.

The authors studied the damage to blood vessels 1 to 2 mm in diameter caused by the most commonly used types of microvascular needle. Excluding variables introduced by anastomosis, the study focused specifically on lesions attributable only to the needle and suture. Scanning electron microscopy revealed four distinct types of lesion. A theory is proposed to explain the mechanisms whereby these lesions were produced, and a needle design is recommended that may aid in minimizing vascular trauma.

The author reports a case in which a subchiasmal carotid-ophthalmic artery aneurysm was clipped through a bifrontal interhemispheric approach. This approach is feasible for carotid-ophthalmic artery aneurysms with a variety of anatomical correlations between the optic nerve and the aneurysmal neck.

Five cases of a congenital berry aneurysm of the internal carotid artery with origin partially intradural and fundus mainly intracavernous are presented. Angiography does not allow a precise definition of the amount of aneurysm that is intradural, a fact of importance when planning treatment of these cases. However, the angiographic features are characteristics of the type and suggest that these aneurysms be grouped together as a separate entity.

Aneurysms of the intracavernous portion of the internal carotid artery may become very large, but they very rarely rupture. A case is described in which rupture of such a lesion resulted in a lethal massive subdural hematoma with transtentorial herniation. This is the second reported case of substantiated intracranial rupture from a wholly intracavernous carotid artery aneurysm.

A fatal rupture of a large paraophthalmic aneurysm 11 months following treatment with detachable balloons is described. This case illustrates the potential consequences of incomplete aneurysm obliteration with endovascular techniques and emphasizes the need for adequate posttreatment evaluation when this method is used for aneurysm therapy.

Nineteen patients underwent a total of 21 stump angioplasty procedures for an occluded internal carotid artery. Indications for surgery included the preparation of the donor vessel for a subsequent extracranial-intracranial bypass procedure, the occurrence of emboli to the intracranial vasculature from the external carotid artery circulation, and the association with symptomatic occlusive disease of the external carotid artery accompanying occlusion of the ipsilateral internal carotid artery. The technique utilized and the results obtained in these 19 patients are presented. In select patients, the removal of an occluded internal carotid artery stump via a stump angioplasty is beneficial in preventing the catastrophic sequela of embolic cerebrovascular disease.

Two cases of atypical fibromuscular hyperplasia of the internal carotid artery (ICA) are reported. These cases are unique because the changes involve the intima of the vessels without involvement of medial structures as seen in the more common form of fibromuscular hyperplasia. Case 1 is only the fourth report of a symptomatic fibromuscular stenosis at the origin of the ICA. Case 2 is the first report of fibromuscular hyperplasia involving the common carotid artery. Changes similar to those in Case 2 (an elongated area of tubular fibromuscular stenosis) have been reported in the ICA. These atypical or intimal forms of fibromuscular hyperplasia appear to be more common in males and blacks, and may be more often unilateral as well.

Neovascularization is observed in complicated atherosclerotic plaques associated with cellular proliferation, plaque hemorrhage, and thrombosis. The angiogenic activity of 278 plaque fragments was tested; the fragments were taken from 12 patients with cerebral ischemia who underwent carotid endarterectomy. Angiogenesis, determined by the sustained ingrowth of new vessels in the rabbit cornea, was induced in 125 (45%) of these fragments. By contrast, angiogenesis was found in only two (2.4%) of 80 control tissues (p less than 0.001): in none of 22 samples of boiled atherosclerotic plaque; in two of 26 samples of normal rabbit carotid artery; and in none of 32 samples of nonatherosclerotic human uterine artery. Histological evaluation revealed that the cellular zones (composed mainly of smooth-muscle cells) were highly angiogenic, with 97 (76%) of 127 samples showing angiogenesis compared with 23 (17%) of 132 acellular fragments that consisted of amorphic, necrotic, calcific, lipid-laden material (p less than 0.001). These results indicate that angiogenesis in vivo is a function of the cellular component of the advanced atherosclerotic plaque, and is not expressed in the normal, stable arterial wall. The fragile new vessels could promote the growth of the plaque or be a source of hemorrhages, microinfarcts, and plaque fissures that convert a stable, silent lesion to an expanding, ulcerated, thrombotic, symptomatic plaque.

Saccular aneurysms arising at locations other than at arterial divisions are extremely rare. The authors describe eight such aneurysms that protruded from the dorsal wall of the internal carotid artery (ICA) and were unrelated to any arterial junction. Radical surgery was performed in all eight cases. The aneurysms were saccular with a fragile wide or semifusiform neck. Intraoperative rupture occurred in three cases. From this experience, it is emphasized that these unusual protruding aneurysms of the dorsal ICA should be clipped with the clip blade parallel to the parent artery. In addition to clipping, complete wrapping with fascia or Bemsheet (cellulose fabric) is often advisable to prevent slippage of clips or postoperative rupture of residual aneurysm.

This report describes a case of bilateral post-traumatic carotid-carotid-cavernous fistulae (CCF), of both typical and atypical types, with delayed clinical deterioration. Unusual neuropathological lesions, distinctive from those due to direct cerebral trauma, are related to combined arterial ischemia and venous hypertension. Atypical CCF is not necessarily a benign disorder. Radiological monitoring is essential to detect spontaneous progressive intracranial shunting, to predict areas that are at risk from venous hypertension, and to identify remote sites of circulatory vulnerability.

A patient with splitting of the optic nerve by a carotid-ophthalmic artery aneurysm is presented. Possible explanations for this previously unreported configuration are discussed.