Bilateral Cavernous Carotid Aneurysms: The Growth Potential of a Contralateral Aneurysm after Therapeutic Unilateral Internal Carotid Artery Occlusion.

BACKGROUND: Although the introduction of flow-diverter stents has been recognized as a major revolution in the treatment of cavernous carotid aneurysms (CCAs), therapeutic internal carotid artery occlusion (TICAO) remains a reliable procedure for alleviating symptoms caused by CCAs. However, TICAO has the potential risk of the enlargement of coexisting aneurysms that are frequently detected in CCA patients. The purpose of this study is to assess the occurrence of the enlargement of aneurysms coexisting with CCAs after TICAO. METHODS: We reviewed medical charts of CCA patients who were managed using unilateral TICAO. Coexisting aneurysms were identified using angiograms obtained before TICAO, and imaging data in long follow-up periods were retrospectively examined to determine the extent of the enlargement after TICAO. RESULTS: Of 12 patients with CCAs, 10 had 12 coexisting aneurysms; 5 of the coexisting aneurysms (41.7%) showed enlargement during a mean follow-up period of 8.1 years, and all enlarged aneurysms were smaller of the bilateral CCAs; the larger CCA had been managed by TICAO. Five of 6 (83.3%) patients with bilateral CCAs showed enlargement of the contralateral aneurysm after TICAO. Two contralateral CCAs showed marked enlargement after TICAO and were subsequently treated with stent-assisted coil embolization. CONCLUSIONS: Contralateral, smaller aneurysms frequently enlarge after unilateral TICAO in patients with bilateral CCAs. The findings emphasize the importance of long-term observation after TICAO and appropriate interventions against enlarging contralateral aneurysms.

Routine aspiration method during filter-protected carotid stenting: histological evaluation of captured debris and predictors for debris amount.

BACKGROUND: A routine aspiration method in filter-protected carotid artery stenting (CAS) has been reported recently in which the proximal internal carotid artery (ICA) blood column was aspirated using an aspiration catheter after postdilatation regardless of flow state on digital subtraction angiography. We examined the debris particles captured by this method. METHODS: The routine aspiration method was used in 71 CAS procedures. In two procedures, captured debris particles were examined histologically. In the remaining 69 procedures, the size and number of debris particles were measured under a stereoscopic microscope, and then relationships between the amount of debris particles and clinical variables were evaluated using multivariate regression analysis. RESULTS: Histologically, the captured debris contained platelet-precipitating, thrombotic, lipid-rich fibrous and calcified material. The number of debris particles ≥1 mm was 19.6 ± 12.1 (mean ± SD) in 60 procedures with normal flow and 25.9 ± 17.2 (mean ± SD) in 9 procedures with slow/stop flow. Multivariate regression analysis demonstrated that extension of a proximal ICA angulation was an independent predictor of the amount of debris particles with a maximum diameter of either ≥1 mm or <1 mm but ≥0.5 mm (p < 0.05). CONCLUSIONS: The captured debris appeared to originate from atheromatous plaques. If the routine aspiration method had not been used in the present series, the debris might have migrated into intracerebral arteries. Restriction of the extension of a proximal ICA angulation might reduce the amount of debris associated with CAS, especially when the proximal ICA angulation is pronounced.

Obstruction of pores in distal protection filters and angiographically-documented flow impairment during carotid artery stenting.

PURPOSE: To determine any relationship between angiographically documented flow impairment associated with the Angioguard XP cerebral protection filter during carotid artery stenting (CAS) and the condition of the pores in the retrieved filter. METHODS: To obtain baseline characteristics of the Angioguard XP, an unused filter was fully expanded and examined photographically from the cephalad end of the device to determine the structure of the pores in the filter basket. Ten pores assembled in a hexagonal pattern made up a pore group, several of which were arranged in 4 concentric rings surround a central hub that did not have any pores. For each ring of pore groups, the ring diameter, number of pore groups, and the mean minimum pore diameter were measured on a plane perpendicular to the long axis of the device. From these, the area of the ring membrane, the area of the pores, and the ratio of pore area to membrane area were calculated for each ring. Filters retrieved from 56 CAS procedures were retrospectively analyzed along with the operative records and intraprocedural angiograms performed after filter placement, predilation, stent placement, postdilation, aspiration of blood, and filter retrieval. The operators classified blood flow immediately before filter retrieval as normal, slow, or stopped. After retrieval, the filter was cut, rinsed with saline, fixed in 10% neutral buffer formalin, and macroscopically and microscopically inspected. The number of the open pores without any obstruction was counted for each ring. RESULTS: Retrieved filters from flow-impaired cases showed a significantly lower percentage of open pores in comparison to normal-flow cases (p<0.05). In some normal-flow cases, however, the obstruction rates were higher than mean obstruction rates of the slow-flow cases. In normal-flow cases, <5% of pores from the center to the second ring of the filter were open; this constituted more than two thirds of the entire filter diameter. CONCLUSION: The flow state on DSA was related to, but did not completely depend on, filter patency. The low patency rate of the filter in normal-flow cases suggested that flow impairment was occurring but could not be detected by the qualitative evaluation of flow on angiography.

Development of cranial nerve palsy shortly after endosaccular embolization for asymptomatic cerebral aneurysm: report of two cases and literature review.

CLINICAL DESCRIPTION: We report two cases of asymptomatic cerebral aneurysm in which cranial nerve palsy (CNP) developed shortly after symbolization. The CNP occurred immediately in case 1, but case 2 showed the CNP 30 h after symbolization. Although both aneurysms had increased in size on follow-up angiography, case 2 who showed dome re canalization resulted in progressive CNP deterioration. CONCLUSION: These findings suggest that the CNP may result not only from mechanical compression by coils but also from inflammation induced by perpendicular thrombosis, and that the prognosis of the CNP may be influenced by dome re canalization. This complication should be kept in mind in treatment for asymptomatic aneurysms adjacent to the cranial nerves.

Cranial nerve palsy following transvenous embolization for a cavernous sinus dural arteriovenous fistula: association with the volume and location of detachable coils.

OBJECT: Transvenous embolization (TVE) for the treatment of a cavernous sinus (CS) dural arteriovenous fistula (DAVF) occasionally causes cranial nerve palsy (CNP). Overpacking of coils is considered to result in CNP. The purpose of this study was to analyze the association of TVE-induced CNP with the volume and location of coils activated in the CS. METHODS: Thirty-one patients with CS DAVFs (33 lesions) underwent TVE. RESULTS: Cranial nerve palsy occurred or was aggravated in 13 cases (39.4%; CNP group). The cumulative volume of activated coils was significantly greater in the CNP group (0.241 +/- 0.172 cm3) than in the non-CNP group (0.119 +/- 0.075 cm3; p < 0.05). Of those lesions with > 0.2 cm3 of coil volume, 77.8% showed immediate aggravation or a new occurrence of CNP after TVE. Five lesions treated with a smaller volume of coils showed a delayed worsening or occurrence of CNP. In cases with induced oculomotor nerve palsy, coils had been densely packed in the superolateral part of the anterior CS. Dense packing in the lateral portion of the posterior CS frequently induced abducent nerve palsy. Although patients harboring lesions with a greater coil volume required a longer recovery time, newly developed or aggravated CNP, related to 84.6% of the lesions, resolved completely. CONCLUSIONS: The cumulative volume and specific locations of coils in the CS correlated with TVE-induced CNP. Overpacking appeared to be the predominant cause of CNP; however, for CNP in cases involving smaller coil volumes, an alternative mechanism may be involved.

Clinical characteristics of arteriovenous malformations in the cerebellopontine angle cistern.

OBJECTIVE Arteriovenous malformations (AVMs) in the cerebellopontine angle cistern (CPAC) are specific lesions that can cause neurovascular compression syndromes as well as intracranial hemorrhage. Although case reports describing the CPAC AVMs, especially those presenting with trigeminal neuralgia (TN), have been accumulating by degrees, the pathophysiology of CPAC AVMs remains obscure. The authors' purpose in the present study was to evaluate the clinical and radiographic features of CPAC AVMs as well as the treatment options. METHODS This study defined a CPAC AVM as a small AVM predominantly located in the CPAC with minimal extension into the pial surface of the brainstem and closely associated with cranial nerves. All patients with CPAC AVMs treated in the authors' affiliated hospitals over a 16-year period were retrospectively identified. Clinical charts, imaging studies, and treatment options were evaluated. RESULTS Ten patients (6 men and 4 women), ranging in age from 56 to 77 years (mean 65.6 years), were diagnosed with CPAC AVMs according to the authors' definition. Six patients presented with hemorrhage, 3 with TN, and the remaining patient developed a hemorrhage subsequent to TN. Seven AVMs were associated with the trigeminal nerve (Group V), and 3 with the facial-vestibulocochlear nerve complex (Group VII-VIII). All patients in Group VII-VIII presented with the hemorrhage instead of hemifacial spasm. Regarding angioarchitecture, the intrinsic pontine arteries provided the blood supply for all CPAC AVMs in Group V. In addition, 5 of 7 AVMs with hemorrhagic episodes accompanied flow-related aneurysms, although no aneurysm was detected in patients with TN alone. With respect to treatment, all patients with hemorrhagic presentation underwent Gamma Knife surgery (GKS), resulting in favorable outcomes except for 1 patient who experienced rebleeding after GKS, which was caused by the repeated rupture of a feeder aneurysm. The AVMs causing TN were managed with surgery, GKS, or a combination, according to the nidus-nerve relationship. All patients eventually obtained pain relief. CONCLUSIONS Clinical symptoms caused by CPAC AVMs occur at an older age compared with AVMs in other locations; CPAC AVMs also have distinctive angioarchitectures according to their location in the CPAC. Although GKS is likely to be an effective treatment option for the CPAC AVMs with hemorrhagic presentations, it seems ideal to obliterate the flow-related aneurysms before performing GKS, although this is frequently challenging. For CPAC AVMs with TN, it is important to evaluate the nidus-nerve relationship before treatment, and GKS is especially useful for patients who do not require urgent pain relief.

Time course and cellular distribution of hsp27 and hsp72 stress protein expression in a quantitative gerbil model of ischemic injury and tolerance: thresholds for hsp72 induction and hilar lesioning in the context of ischemic preconditioning.

The distribution and time course of expression of the heat shock/stress proteins, hsp27 and hsp72, were evaluated in a highly controlled gerbil model of ischemic injury and tolerance induction, in which the duration of ischemic depolarization in each hippocampus provides a precise quantitative index of insult severity. Gerbils were subjected to brief priming insults (2- to 3.5-minute depolarization) that produce optimal preconditioning, to severe test insults (6- to 8.5-minute depolarization) that produce complete CA1 neuron loss in naive animals, or to combined insults administered 1 week apart, after which almost complete tolerance to CA1 neuron injury is observed. Immunoreactivities of hsp27, hsp72, glial fibrillary acidic protein and microtubule-associated protein 2 (MAP2) were evaluated in animals perfused at defined intervals after the final insult in each treatment group, using a variation of established antigen-retrieval procedures that significantly improves detection of many proteins in vibratome brain sections. Hsp72 was detected in CA1 neurons of some hippocampi 2 to 4 days after preconditioning, but this was only seen after the longest priming depolarizations, whereas shorter insults that still induced optimal tolerance failed to induce hsp72. Hsp72 was induced after test insults in preconditioned hippocampi, but at a higher depolarization threshold than observed for naive animals. An astrocytic localization of hsp27 was observed in regions of neuron injury, as indicated by reduced MAP2 immunoreactivity, and was primarily restricted to dentate hilus after preconditioning insults. These results establish that limited hilar lesions are characteristic of optimal preconditioning, whereas prior neuronal expression of either hsp72 or hsp27 is not required for ischemic tolerance.

CCAAT/enhancer binding proteins are expressed in the gerbil hippocampus after transient forebrain ischemia.

We analyzed CCAAT/enhancer binding protein (C/EBP) family protein levels during reperfusion after a single episode of sublethal forebrain ischemia in the gerbil hippocampus to investigate their expression after ischemia and correlation with neuronal cell death. The common carotid arteries were surgically exposed bilaterally and occluded for 10 min to induce forebrain ischemia in adult Mongolian gerbils. C/EBPalpha, beta, delta, epsilon, zeta protein immunoreactivity was expressed in the hippocampal layer of the CA1 region at 72 h after ischemia and peaked at 96 h. These results appear to correlate with neuronal degeneration as shown by hematoxylin and eosin staining and DNA fragmentation in the terminal transferase biotinylated-UTP nick end labeled-method. The present results demonstrate that C/EBP family proteins appear in the selectively vulnerable CA1 pyramidal cell layer in gerbils during neuronal degeneration, and may serve as a signal that neurons are progressing to neuronal cell death and DNA fragmentation.

Successful removal of a huge hypervascular tentorial cavernous angioma after preoperative endovascular embolization.

The authors report a rare case of a huge hypervascular tentorial cavernous angioma treated with preoperative endovascular embolization, followed by successful gross-total removal. A 15-year-old girl presented with scintillation, diplopia, and papilledema. Computed tomography and MRI studies revealed a huge irregularly shaped tumor located in the right occipital and suboccipital regions. The tumor, which had both intra- and extradural components, showed marked enhancement and invasion of the overlying occipital bone. Angiography revealed marked tumor stain, with blood supply mainly from a large branch of the left posterior meningeal artery. Therefore, this lesion was diagnosed as a tentorium-based extraaxial tumor. For differential diagnosis, meningioma, hemangiopericytoma, and malignant skull tumor were considered. Tumor feeders were endovascularly embolized with particles of polyvinyl alcohol. On the following day, the tumor was safely gross totally removed with minimum blood loss. Histopathological examination confirmed the diagnosis of cavernous angioma. To date, there have been no reports of tentorium-based cavernous angiomas endovascularly embolized preoperatively. A tentorial cavernous angioma is most likely to show massive intraoperative bleeding. Therefore, preoperative embolization appears to be quite useful for safe maximum resection. Hence, the authors assert that the differential diagnosis of tentorium-based tumors should include tentorial cavernous angioma, for which preoperative endovascular embolization should be considered.

Long-term follow-up of intra-aneurysmal coil embolization for unruptured paraclinoid aneurysms.

OBJECTIVES: The selection of therapeutic modalities, including endovascular coil embolization and surgical clipping, for management of unruptured paraclinoid aneurysms, remains controversial. Detailed long-term outcome data for endovascular coil embolization of unruptured paraclinoid aneurysms are still lacking. Thus, we evaluated the safety and efficacy of coil embolization of unruptured paraclinoid aneurysms. METHODS: From January 1998 to July 2010, 138 patients underwent endovascular coiling for 140 unruptured paraclinoid aneurysms. Their medical records and radiologic images were reviewed retrospectively. RESULTS: Complications occurred in 5·7% of 140 procedures and the morbidity rate was 0·7%. Of the 140 unruptured paraclinoid aneurysms, a total of 111 aneurysms underwent follow-up imaging evaluation at 2 years or more, or showing reopening on imaging studies within 2 years (65·6±37·2 months). Multivariate analysis revealed two predictors for reopening of the aneurysms: a maximum diameter of aneurysms and a dome/neck ratio of aneurysms (P<0·05). Reopening rates of aneurysms with maximum sizes of <8, 8-10, and >10 mm were 1%, 25%, and 75%, respectively. Reopening rates were significantly different among the three groups (P<0·05). In aneurysms with a maximum diameter of 8-10 mm, there was a significant difference of dome/neck ratios between the presence and absence of reopened aneurysms (P<0·05). DISCUSSION: The results indicate that endovascular coil embolization is a safe and effective treatment modality in selected patients with unruptured paraclinoid aneurysms. Consideration of the aneurysm size and the dome/neck ratio could assist in the selection of therapeutic modalities for these aneurysms.

Flow impairment during filter-protected carotid artery stent placement: frame-by-frame evaluation of digital subtraction angiography images.

OBJECTIVE: To evaluate quantitatively flow impairment of contrast medium on digital subtraction angiography (DSA) performed before and after filter retrieval following carotid artery stent (CAS) placement with distal filter protection. METHODS: Retrospective analysis was performed of 55 CAS placement procedures with distal filter protection in 51 patients. From a qualitative analysis, the operators determined if there was flow reduction of contrast medium on digital subtraction angiography (DSA) before filter retrieval. A quantitative analysis was performed of frame-by-frame images before and after filter retrieval to compare the flow state of contrast medium. RESULTS: Stop-flow or slow-flow classified by the operators during CAS placement was found in 10 (18%) of 55 procedures. However, the frame-by-frame analysis of DSA images showed flow reduction of contrast medium in 46 (84%) of 55 procedures. Among 45 procedures with normal-flow as classified by the operators, 36 (80%) procedures showed ≥1 frames with delay of contrast medium based on quantitative analysis. CONCLUSIONS: The frame-by-frame comparison of angiographic images revealed a much higher incidence of blood flow impairment on DSA before filter retrieval compared with the operators' classification during CAS placement procedures. Considering the high incidence of blood flow impairment, the possibility of stagnation of blood flow in the internal carotid artery (ICA) column should be expected during every CAS placement procedure.

Intra-aneurysmal coil embolization for large or giant carotid artery aneurysms in the cavernous sinus.

This study evaluated the effectiveness of intra-aneurysmal coil embolization for large or giant carotid artery aneurysms in the cavernous sinus in seven patients treated by intra-aneurysmal coil embolization from 2001 to 2010. Only one patient showed improved neurological symptoms caused by aneurysmal mass effect during the mean follow-up period of 53.4 ± 27.3 months. Neurological symptoms caused by the aneurysms remained unchanged in two patients, and deteriorated in four. Intra-aneurysmal coil embolization is not considered an effective treatment option for large or giant carotid artery aneurysms in the cavernous sinus.

Usefulness of motor-evoked potential monitoring during coil embolization of anterior choroidal artery aneurysms: technical reports.

OBJECTIVES: To determine whether transcranial motor-evoked potential (TCMEP) monitoring is useful for detecting blood flow insufficiency in the anterior choroidal artery (AChA) and reflects motor function during coil embolization of AChA aneurysms. METHODS: We analysed MEP findings in seven patients who underwent coil embolization for AChA aneurysms. Corkscrew electrodes positioned at C3 and C4 were used to deliver supra-maximal stimuli (230-550 V). TCMEPs were recorded from the brachioradialis, abductor pollicis brevis, anterior tibialis, and abductor hallucis muscles during all endovascular surgery procedures. RESULTS: Three of seven patients showed transient decreases in TCMEP amplitudes obtained from the lower extremities after coil insertion into the aneurysms, although digital subtraction angiography (DSA) showed no blood flow insufficiency in the AChAs. In two of these three patients, extraction of the coils resulted in recovery of TCMEP amplitudes. In the other patient, the amplitude recovered gradually during repeated TCMEP recordings. One of the three patients experienced transient hemiparesis and aphasia 3 hours after treatment. No patients experienced permanent morbidity post-operatively. DISCUSSION: Decreases in TCMEP amplitude during endovascular treatment for AChA aneurysms are likely to reflect motor dysfunction due to a subtle blood flow insufficiency in the AChA, not detectable by DSA. TCMEP monitoring is a simple and safe monitoring method during coil embolization of AChA aneurysms.

Routine use of debris aspiration before retrieval of distal filter protection devices in carotid arterial stenting: analysis of captured debris and evaluation of clinical results.

BACKGROUND: Distal filter protection allows for continuous cerebral perfusion during carotid artery stenting (CAS), although a higher risk of debris migrating into the cerebral arteries compared with other protection systems has been reported. OBJECTIVE: To improve the extent of debris capture, we used routine aspiration of blood located proximal to the filter in the internal carotid artery blood column before retrieval of the filter device. METHODS: Of 71 CAS procedures with distal filter protection, routine aspiration was performed in 41 procedures. The size and number of debris particles in each aspirated blood sample were measured under a stereoscopic microscope in 30 consecutive procedures with routine aspiration. Occurrence of periprocedural neurological events was compared between 41 procedures with routine aspiration and the other 30 without routine aspiration. RESULTS: In the aspirated blood, debris particles ≥ 500 µm and ≥ 1000 µm in the longest diameter were observed in 30 (100%) and 28 (93.3%) procedures, respectively. The number of particles ≥ 1000 µm was significantly larger in the second through fourth blood aspirates vs the first aspirate (P < .05). Occurrence of periprocedural neurological events was significantly less frequent in the routine aspiration group (0 of 41 procedures) than in the conventional method group (7 of 30 procedures) (P < .05). CONCLUSION: The use of routine aspiration during CAS with distal filter protection possibly reduced periprocedural neurological events by increasing the proportion of debris captured. To improve the capture of debris particles, at least 4 repeated aspirations are advisable during each CAS procedure.

Sturge-Weber syndrome associated with arteriovenous malformation in a patient presenting with progressive brain edema and cyst formation.

Sturge-Weber syndrome (SWS) is a neurocutaneous disorder presenting with a facial port-wine stain, along with an occipital leptomeningeal angiomatosis that is typically located ipsilateral to the stain. In this paper, the authors present a rare case of SWS associated with an arteriovenous malformation (AVM) instead of an angiomatosis in the ipsilateral occipital lobe. While the patient was in the care of the authors, the AVM progressively enlarged, and was accompanied by progressive stenoocclusive changes of the venous system. The resulting brain edema finally brought about a serious neurological condition 13 years after the initial diagnosis. Transarterial embolization and medical treatments decreased the edema. Subsequently, however, a large intraparenchymal cyst appeared, aggravating the patient's motor weakness. Aspiration of the cyst ameliorated these symptoms. The analysis of the fluid from the cyst revealed that it contained a very high concentration of protein. Although there is no proven pathogenic mechanism to explain these protein concentrations and the enlargement of the AVM, the authors hypothesize that the progressive edema resulted from a synergic augmentation of the inflow from the AVM and the progressive obstruction of venous drainage that is a hallmark of SWS. The formation of the cyst probably resulted from the blood vessel hyperpermeability that is inherent to SWS.

Modified buddy wire technique for coil embolization of posterior circulation aneurysms.

INTRODUCTION: In coil embolization of a posterior circulation aneurysm, tortuosity or a small vessel caliber frequently prevents placement of a guiding catheter in the vertebral artery. Even in such difficult situations, however, coil embolization is the only treatment option when the patient's clinical condition is very poor, or the aneurysm is inaccessible by microsurgery. METHODS: Three patients with a posterior circulation aneurysm were treated by coil embolization with the use of a modified buddy wire technique to stabilize a guiding catheter that could not be placed into the vertebral artery. RESULTS: The guiding catheter was stabilized in the subclavian artery and the microcatheter was firmly supported. As a result, coil embolization was performed safely in all patients. There were no procedural complications. CONCLUSION: The modified buddy wire technique could provide patients with a chance to undergo endovascular surgery despite having a tortuous or narrow vertebral artery.