Clinicopathological features of non-atherosclerotic cerebral arterial trunk aneurysms

Bifurcation dissecting aneurysm: tips and tricks to differentiate from saccular aneurysm

Bifurcations are a common site for saccular aneurysms, but rarely can be a site for dissecting aneurysms. Identification of these aneurysms is extremely important because the management plan depends on it. We describe a rare case of a ruptured dissecting aneurysm at the right ICA bifurcation in a pre-teen child which posed a diagnostic dilemma but ultimately was successfully managed with flow diversion.

Altered expression of circular RNA in patients with cervical artery dissection

Cervical artery dissection (CeAD), a special cerebrovascular disease and the main cause of stroke in young people, can present with ischemic stroke, headache, subarachnoid hemorrhage, and other symptoms, increasing the possibility of misdiagnosis. As a special class of non-coding RNAs, circRNAs are commonly found in organisms and can play regulatory roles in transcription and post-transcription processes, affecting gene expression.CircRNAs have reported to be associated with neurological diseases; however, their role in CeAD has not been discerned. In this study, we aimed to elucidate the pathophysiological changes in patients with CeAD and identify biomarkers. Peripheral blood mononuclear cells from patients with CeAD and healthy controls were sequenced using high-throughput sequencing. We detected 460 differently expressed circRNAs in patients with CeAD (p < 0.5, fold difference ≥ 2), of which 240 were upregulated and 220 were downregulated. Four circRNAs showed significant differences in expression, which were validated using qRT-PCR. These results suggested that three circRNAs were consistent with high-throughput sequencing results. Bioinformatics analysis demonstrated that these differentially expressed circRNAs were involved in protein metabolism, regulation, synapses, and other pathophysiological processes during CeAD-induced stroke. Additionally, various pathways related to inflammation were closely associated with circRNAs. Based on our results, we suggest that the aberrant expression of circRNAs in CeAD may serve as a biomarker for its diagnosis and as a potential therapeutic target.

Deconstructive versus reconstructive endovascular approaches for intracranial dissecting aneurysms

Background

The annual incidence of the intracranial dissecting aneurysms is about 1 to 1.5 per 100,000. This is a well-known cause of stroke and subarachnoid hemorrhage in young and middle-aged patients (Santos-Franco et al. in Neurosurg Rev, 2008. https://doi.org/10.1007/s10143-008-0124-x). Various surgical and endovascular treatment methods have been proposed for intracranial dissecting aneurysms. All treatment methods aim to reduce the blood flow in the dissected region. Deconstructive techniques sacrifice the parent artery, whereas reconstructive techniques aim to maintain a parent artery (Stéphanie et al. in Lancet Neurol 14(6):640–654, 2015. https://doi.org/10.1016/S1474-4422(15)00009-5). Due to its dissecting nature, wall friability can make surgical clipping difficult and even risky. On the other hand, recanalization after coiling alone is almost certain. Therefore, deconstructive modalities of treatment like trapping or parent vessel occlusion, performed either surgically or endovascularly, have predominated for managing those lesions, usually with good results. Nevertheless, in absence of efficient collateral pathways, the deconstructive technique carries an ischemic risk. In situations in which parent artery preservation is mandatory, the use of stent-assisted techniques may be the most appropriate choice (de Barros Faria et al. in Am J Neuroradiol 32(11):2192–2195, 2011. https://doi.org/10.3174/ajnr.A2671). However, the usage of stent with recently ruptured aneurysms is always perplexing due to the necessity of dual antiplatelet administration. Hence the management of dissecting aneurysms remain challenging.

Results

Between January 2017 and July 2019, 19 patients presenting with intracranial dissecting aneurysms were referred to our department for endovascular treatment. Among the nineteen patients, 11 cases were treated by parent artery occlusion representing 57.9% of the cases, and 7 cases (36.8%) were treated by artery preserving technique, and only one case (5.3%) was treated by combination of parent artery occlusion and artery preserving technique. One week after the intervention 26.3% of patients had no disability (mRS = 0), 47.4% had no significant disability (mRS = 1), 15.8% had slight disability (mRS = 2) and 10.5% had moderate to severe disability (mRS = 3–4). After three months we found an overall improvement of the clinical outcome, as 57.9% of patients had no disability (mRS = 0), 26.3% had no significant disability (mRS = 1) and 15.8% had mild disability (mRS = 2). Finally, after six months reassessment with angiography showed that 89.5% of patients had stable aneurysmal occlusion, and 10.5% had recurrence of aneurysm.

Conclusions

Both endovascular approaches, whether parent artery occlusion or artery preserving technique showed favorable outcome which indicates the safety and efficacy of both approaches if selected properly according to the morphology of the aneurysm.

Intracranial Fusiform and Circumferential Aneurysms of the Main Trunk: Therapeutic Dilemmas and Prospects

Intracranial fusiform and circumferential aneurysms (IFCAs), especially those located on the main trunk, are uncommon and difficult to manage. Currently, literature focused on IFCAs on the main trunk of cerebral arteries is lacking. The treatment of IFCAs is still under debate. Therefore, in this review, we further explore the treatment of this complicated entity. In addition, we also present some interesting cases. Based on the literature review and our experience, we found that IFCAs are often located in the vertebrobasilar system and that ruptured or large symptomatic IFCAs are associated with increased mortality and higher rebleeding rates. The treatment strategies for IFCAs can be classified as deconstructive and reconstructive methods via open surgery and/or endovascular treatment (EVT). Currently, EVT is a popular method and the main therapeutic choice. In particular, flow diversion has revolutionized the treatment of IFCAs. Parent artery occlusion (PAO) with or without revascularization may still be considered a suitable choice. Complex IFCAs that cannot be resolved by EVT can also be treated via open surgery with or without extracranial–intracranial bypass. Targeted embolization for the weak points of IFCAs is a temporary or palliative choice that is rarely used. In summary, despite complications, both surgical treatment and EVT are effective options for appropriately selected cases. Due to the development of endovascular implants, EVT will have better prospects in the future.

A scoring system to discriminate blood blister-like aneurysms: a multidimensional study using patient-specific model

Presurgical discrimination of blood blister-like aneurysms (BBAs) can assist neurosurgeons in clinical decision-making. The aim of this study was to investigate the characteristics of BBAs and construct a useful tool to distinguish BBAs. This study reviewed patients with small/median, hemispherical, and wide-necked aneurysms of the internal carotid artery in our institution. BBAs were identified via their intraoperative findings. A hemodynamic analysis was performed using a patient-specific model. The independent risk factors of BBAs were investigated using a logistic analysis. A scoring system was then established to discriminate BBAs, in which its predicting value was analyzed using receiver operating characteristic (ROC) analysis. A total of 67 aneurysms comprising 21 BBAs were enrolled. Comparing features between BBAs and non-BBAs, statistical significances were found in the aspect ratio (AR), height-to-width ratio, aneurysm angle (AA), wall shear stress gradient (WSSG), and normalized wall shear stress average. A multivariate logistic analysis identified AR (OR = 0.29, p = 0.021), WSSG (OR = 1.54, p = 0.017) and AA (OR = 2.49, p = 0.039) as independent risk factors for BBAs. A scoring system was constructed using these parameters, effectively distinguishing BBAs (AUC = 0.931, p < 0.01). Our multidimensional scoring system may effectively assist in the discrimination of BBAs from wide-necked non-BBAs.

Dilated Cerebral Arteriopathy in Classical Pompe Disease: A Novel Finding

BACKGROUND

In Pompe disease, glycogen deposition results in an augmentation of blood flow and abnormal remodeling, with resultant weakening of the arterial walls, which may result in pathologic dilatation of the cerebral arteries. This complication is rare in patients with late-onset Pompe disease, but it has not been well-described in infantile-onset Pompe disease. The effect of enzyme replacement therapy on this process is not known.

METHODS

We examined clinical and imaging data on two patients who exhibit cerebrovascular arteriopathy: a 14-year-old boy with infantile-onset Pompe disease on enzyme replacement therapy and a 23-year-old woman with late-onset Pompe disease who was also receiving enzyme replacement therapy.

RESULTS

Our 14-year-old patient exhibits cerebrovascular arteriopathy, primarily proximal and vertebrobasilar, while the 23-year-old patient has a more diffuse pattern. The 14-year-old patient is unique because cerebral dolichoectasias have not been described in infantile-onset Pompe disease. The 23-year-old patient is notable given the age and history of enzyme replacement therapy since age 15 years.

CONCLUSIONS

Dilative cerebral arteriopathy in infantile-onset Pompe disease is novel and similarly atypical is the diffuse vascular dilation seen in our young patient with late-onset Pompe disease, both receiving enzyme replacement therapy. We should be cognizant of the risk of cerebrovascular disease in Pompe disease regardless of the disease variant and enzyme replacement therapy status.

Characteristics and Clinical Course of Fusiform Middle Cerebral Artery Aneurysms According to Location, Size, and Configuration

OBJECTIVE

To analyze the angiographic features and clinical course, including treatment outcomes and the natural course, of fusiform middle cerebral artery aneurysms (FMCAAs) according to their location, size, and configuration.

METHODS

We reviewed the literature on adult cases of FMCAAs published from 1980 to 2018; from 25 papers, 112 FMCAA cases, for which the location, size, and configuration could be identified, were included in this study. Additionally, 33 FMCAA cases in our hospital were included, from which 16 were assigned to the observation group. Thus, a total of 145 adult FMCAA cases were included. We classified the FMCAAs according to their location (l-type 1, beginning from prebifurcation; l-type 2, beginning from bifurcation; l-type 3, beginning from postbifurcation), size (small, <10 mm; large, ≥10 mm; giant, ≥25 mm), and configuration (c-type 1, classic dissecting aneurysm; c-type 2, segmental ectasia; c-type 3, dolichoectatic dissecting aneurysm).

RESULTS

The c-type 3 was more commonly diagnosed with ischemic symptoms (31.8%) than hemorrhage (13.6%), while 40.9% were found accidentally. In contrast, c-type 2 was more commonly diagnosed with hemorrhagic symptoms (14.9%) than ischemic symptoms (10.6%), and 72.3% were accidentally discovered. According to location, ischemic symptoms and hemorrhage were the most frequent symptoms in l-type 1 (28.6%) and l-type 3 (34.6%), respectively. Most of l-type 2 FMCAAs were found incidentally (68.4%). Based on the size of FMCAAs, only 11.1% of small aneurysms were found to be hemorrhagic, while 18.9% and 26.0% of large and giant aneurysms were hemorrhagic, respectively. Although four aneurysms of the 16 FMCAAs in the observation group increased in size and one aneurysm decreased in size during the observation period, no rupture was seen in any case and there were no significant predictors of aneurysm enlargement. Of 104 FMCAAs treated, 14 cases (13.5%) were aggravated than before surgery and all the aggravated cases were l-type 1.

CONCLUSION

While ischemic symptoms occurred more frequently in l-type 1 and c-type 3, hemorrhagic rather than ischemic symptoms occurred more frequently in l-type 3 and c-type 2. In case of l-type 1 FMCAAs, more caution is required in determining the treatment due to the relatively high complication rate.

Pathogenesis of dorsal internal carotid artery wall aneurysms based on histopathologic examination and microscopic configuration

Blood blister-like aneurysms (BBAs) are an important cause of subarachnoid hemorrhage (SAH), but proper treatment is uncertain due to the poor prognosis of these aneurysms. The pathogenesis of BBAs remains unclear and few studies have reported on histological examinations of BBAs because it is difficult to obtain a specimen due to a high risk of intraoperative bleeding. In this report, BBAs were histopathologically examined in two patients who presented with SAH due to rupture of a BBA that was treated with surgical trapping and bypass surgery. BBA specimens including the adjacent internal carotid artery (ICA) walls were obtained intraoperatively. We suggest the pathogenesis of BBAs based on histopathologic examination and microscopic configuration.

Ruptured dissecting aneurysm in communicating internal carotid artery segments treated using a stent-assisted endovascular technique

Hemorrhagic intracranial dissecting aneurysms are known to have a poor natural history and an increased tendency to rebleed. The communicating segment of the internal carotid artery (ICA) is an infrequent site of dissection that is difficult to manage using deconstructive endovascular treatment because of the need to preserve important vascular branches. We report two cases of ruptured dissecting aneurysms that occurred in communicating segments of the ICA and treated using a reconstructive endovascular technique involving stent-assisted coiling. Case 1 was a 59-year-old woman who was diagnosed with subarachnoid hemorrhage (SAH). Digital subtraction angiography (DSA) indicated a ruptured dissecting aneurysm that arose from the left communicating segment of the ICA. Stent-assisted coiling was performed and followed by a second overlapping stent technique. No deterioration was observed on DSA after one week of follow-up or on magnetic resonance angiography (MRA) after four months of follow-up. The patient was discharged without neurological complications (Glasgow Outcome Scale 5). Case 2 was a 34-year-old man who was admitted with a diagnosis of SAH. DSA revealed a suspected lesion of a ruptured dissecting aneurysm of the left communicating segment of the ICA. Stent-assisted coiling was performed, and partial occlusion was achieved. No deterioration was observed on DSA after two weeks of follow-up or on MRA after six months of follow-up. The patient was discharged without neurological complications (Glasgow Outcome Scale 5). These cases suggest that using stent-assisted coiling could be a feasible modality for treating ruptured ICA dissecting aneurysms in the communicating segment.

Clinical and Imaging Characteristics of Diffuse Intracranial Dolichoectasia

BACKGROUND AND PURPOSE

Among patients with vertebrobasilar dolichoectasia is a subset of patients with disease affecting the anterior circulation as well. We hypothesized that multivessel intracranial dolichoectasia may represent a distinct phenotype from single-territory vertebrobasilar dolichoectasia. The purpose of this study was to characterize clinical characteristics and angiographic features of this proposed distinct phenotype termed "diffuse intracranial dolichoectasia" and compare them with those in patients with isolated vertebrobasilar dolichoectasia.

MATERIALS AND METHODS

We retrospectively reviewed a consecutive series of patients with diffuse intracranial dolichoectasia and compared their demographics, vascular risk factors, additional aneurysm prevalence, and clinical outcomes with a group of patients with vertebrobasilar dolichoectasia. "Diffuse intracranial dolichoectasia" was defined as aneurysmal dilation of entire vascular segments involving ≥2 intracranial vascular beds. Categoric and continuous variables were compared by using χ² and Student t tests, respectively.

RESULTS

Twenty-five patients had diffuse intracranial dolichoectasia, and 139 had vertebrobasilar dolichoectasia. Patients with diffuse intracranial dolichoectasia were older than those with vertebrobasilar dolichoectasia (70.9 ± 14.2 years versus 60.4 ± 12.5 years, P = .0002) and had a higher prevalence of abdominal aortic aneurysms (62.5% versus 14.3%, P = .01), other visceral aneurysms (25.0% versus 0%, P < .0001), and smoking (68.0% versus 15.9%, P < .0001). Patients with diffuse intracranial dolichoectasia were more likely to have aneurysm growth (46.2% versus 21.5%, P = .09) and rupture (20% versus 3.5%, P = .007) at follow-up. Patients with diffuse intracranial dolichoectasia were less likely to have good neurologic function at follow-up (24.0% versus 57.6%, P = .004) and were more likely to have aneurysm-related death (24.0% versus 7.2%, P = .02).

CONCLUSIONS

The natural history of patients with diffuse intracranial dolichoectasia is significantly worse than that in those with isolated vertebrobasilar dolichoectasia. Many patients with diffuse intracranial dolichoectasia had additional saccular and abdominal aortic aneurysms. These findings suggest that diffuse intracranial dolichoectasia may be a distinct vascular phenotype secondary to a systemic arteriopathy affecting multiple vascular beds.

The insidious appearance of the dissecting aneurysm: Imaging findings and related pathophysiology. A report of two cases

Intracranial dissecting aneurysms have been frequently reported to present with fairly challenging and time-variable imaging findings that can be mostly explained by the pathological mechanisms that underline the dissection. We present two cases of spontaneous dissecting aneurysm of the supraclinoid ICA, both clinically presenting with SAH, but characterized by different progression of clinical symptoms and imaging. However, in both cases an outpouch and a mild fusiform dilation of the supraclinoid ICA was present in the initial CTA performed after the occurrence of symptoms. These findings were well depicted by the MPR reformats performed retrospectively. We postulate that this finding may represent the point of initial transmural dissection and we recommend that careful analysis of the CTA MRP reformatted images should be performed in order to detect this finding promptly.

A small animal model for early cerebral aneurysm pathology

Prior studies, using systemic hypertension and elastase infusion, have induced cerebral aneurysm (CA) formation in mice. However, the CAs induced were rapidly formed, relatively large, and often ruptured. These features are not completely representative of human CAs. We set out to develop a mouse model representative of the early pathological features of human CA. Twenty male C57/BL6 mice were placed in a stereotactic frame. Low dose elastase solution (2μl/min) was manually injected into the right basal cistern. Human angiotensin II (0.11μl/h) was infused subcutaneously. Mice were observed for 2-3weeks prior to euthanasia. Early CA histopathological features including endothelial change (EC) and internal elastic lamina degeneration (IELD) were systematically sought at major cerebral arterial bifurcations. Brains were harvested from 11 of 15 mice, yielding 27 bifurcations. Sub-arachnoid haemorrhage (SAH) without CA formation was observed in one brain. Macroscopic CA without SAH was observed in another brain. Early CA features were observed in 8/11 (73%) brains. All bifurcations with IELD demonstrated EC: where EC was absent, IELD was also absent. EC severity appeared to correlate with IELD severity. EC and IELD were both severe within the CA. Using lower dose elastase solution than previously employed, we developed a model of early CA pathology. Our model demonstrated that the spectrum of known early CA pathology can be created at multiple bifurcations in mice, with EC severity appearing to correlate with IELD severity. This model permits the study of factors which potentially advance or retard the progression of CA formation.

Cerebral aneurysms associated with segmental dilative arteriopathy of the circle of Willis

BACKGROUND

Dilative arteriopathy is a form of dolichoectasia. It is sometimes observed in the posterior circulation, and it may be associated with various type of stroke. Herein, we report two unusual cases of saccular aneurysms associated with a segmental dilative arteriopathy located in the anterior circulation.

CASE DESCRIPTIONS

The first case is a 39-year-old woman with irregular tortuosity and coiling of the left internal cerebral artery along with saccular aneurysms in this artery. The second case is a 45-year-old woman presenting with a ruptured saccular aneurysm in the coiling of the anterior cerebral artery. In both cases, the aneurysm was clipped successfully, and the patients recovered uneventfully with no neurological deficits.

CONCLUSION

Dilative arteriopathy of the circle of Willis is an unusual anomaly and is characterized by tortuous and elongated arteries, which are sometimes observed in patients with a congenital anomaly. This report describes two cases of saccular aneurysm associated with dilative arteriopathy of the circle of Willis with no medical history, which to the best of our knowledge has not previously been described.

Fusiform superior cerebellar artery aneurysm treated with STA-SCA bypass and trapping

BACKGROUND

Fusiform aneurysms of cerebellar arteries are rare. Different surgical techniques to address these challenging lesions have been described, and their application depends on whether the goal is to maintain the flow in the parent vessel or to occlude it.

CASE DESCRIPTION

The authors reported a case of a fusiform aneurysm located in the lateral pontomesencephalic segment of the superior cerebellar artery (SCA) in a 32-year-old man who presented with subarachnoid hemorrhage. The patient was subjected to aneurysm trapping followed by a bypass between the superficial temporal artery (STA) and SCA and had an uneventful recovery.

CONCLUSIONS

Although only a few cases of fusiform aneurysms in the supracerebellar artery have been reported in the literature, the treatment strategies adopted were diverse. In selected cases of patients in good neurological condition with ruptured fusiform aneurysms at the proximal segments of SCA and who have poor evidence of collateral supply, the possibility of a STA-SCA bypass with aneurysm trapping must be considered. A review of the current treatment modalities of this pathology is also presented.

Treatment of ruptured intra-cranial internal carotid artery dissection using a flow-diverter stent

In the presence of associated subarachnoid hemorrhage, the treatment of arterial dissection can be classified as either deconstructive (involving occlusion or sacrifice of the parent vessel) or reconstructive (preserving blood-flow through the parent vessel). In both treatment strategies, the main goal is to prevent any further risk of rebleeding. However, reconstructive treatment is reserved only for those patients in whom occlusion of the parent vessel is not feasible due to an insufficient collateral supply. This report is of a case of intra-cranial carotid artery dissection treated by a reconstructive endovascular approach, with deployment of a flow-diverter stent, for the management of an associated subarachnoid hemorrhage. This is, to the authors' knowledge, the first report of the use of a flow-diverter device as the main treatment of a ruptured supraclinoid carotid artery dissection.

Pathomechanisms and treatment of pediatric aneurysms

Pediatric aneurysms are rare diseases distinct from classical adult aneurysms and therefore require different treatment strategies. Apart from saccular aneurysms that are more commonly found in older children, three major pathomechanisms may be encountered: trauma, infection, and dissection. The posterior circulation and more distal locations are more commonly encountered in children compared to adults, and there is an overall male predominance. Clinical findings are not only confined to subarachnoid hemorrhage but may also comprise mass effects, headaches or neurological deficits. In traumatic aneurysms, the skull base and distal anterior communicating artery are commonly affected, and the hemorrhage occurs often delayed (2-4 weeks following the initial trauma). Infectious aneurysms are mostly bacterial in origin, and hemorrhage occurs early after a septic embolic shower. Dissecting aneurysms are the most often encountered aneurysm type in children and can lead to mass effect, hemorrhage, or ischemia depending on the fate of the intramural hematoma. Treatment strategies in pediatric aneurysms include endosaccular coil treatment only for the "classical berry-type" aneurysms; in the other instances, parent vessel occlusion, flow reversal, surgical options, or a combined treatment with bypass and parent vessel occlusion have to be contemplated.

Fusiform dilation of the carotid artery following radical resection of pediatric craniopharyngiomas: natural history and management

OBJECT

Fusiform dilation of the supraclinoid internal carotid artery (FDCA) is a reported occurrence following surgery for suprasellar tumors, in particular craniopharyngiomas. We report our experience of the incidence and natural history of FDCA following aggressive surgical resection of craniopharyngiomas in children.

METHODS

Between 1986 and 2006, 86 patients under the age of 21 underwent radical resection of craniopharyngiomas at our institution. Ten cases with < 1 year of follow-up imaging (6), perioperative death (3), or nonsuprasellar tumors (1) were excluded. Data were retrospectively collected on the remaining 76 patients (43 male, 33 female; mean age 9.5 years; mean tumor size 3.3 cm) to determine the risk factors for and the rate and clinical significance of FDCA.

RESULTS

Fifty patients had primary tumors and 26 patients received treatment before referral to our center. Sixty-six children (87%) had gross-total resection. At a mean follow-up time of 9.9 years, FDCA had developed in 7 patients (9.2%), all of whom had primary tumors and gross-total resection. The mean time to onset of FDCA was 6.8 months (range 3-11 months) with stabilization occurring at mean of 17.7 months (range 9-29.5 months). The mean size of the aneurysms was 9.1 mm (range 7.1-12 mm). After arrest, no lesions showed continued growth on serial imaging or produced symptoms or required treatment. There were no significant differences in age, sex, tumor size, pre- or retrochiasmatic location, extent of resection, or surgical approach (p > 0.05) between patients with and without FDCA.

CONCLUSIONS

Fusiform dilation of the supraclinoid internal carotid artery occurred in almost 10% of children following radical resection of craniopharyngiomas. In agreement with other reports, the authors concluded that FDCA probably occurs as a result of surgical manipulation of the supraclinoid carotid artery and should be managed conservatively because very few patients exhibit continued symptoms or experience growth or rupture of the lesion.

The many faces of intracranial arterial dissections

Intracranial arterial dissecting diseases are rare and challenging diseases with a high associated morbidity and mortality. Their common pathomechanic origin is related to blood entering the vessel wall via an endothelial and intimal tear. Depending on the fate of the thus established intramural hematoma, different symptoms may ensue including mass effect, subarachnoid hemorrhage or ischemia. If the mural hematoma ruptures all vascular layers of the intradural artery, a subarachnoid hemorrhagic will occur. If the intramural hematoma reopens distally into the parent vessel on the other hand, ischemic embolic events may happen following intramural clot formation. If the mural hematoma does neither open itself into the parent vessel nor into the subarachnoid space, the vessel wall may dilate leading to occlusion of perforator branches and local ischemia. Organization of the mural hematoma may result in a chronic dissecting process which may eventually lead to formation of a "giant partially thrombosed" aneurysm with thrombus of varying ages within the vessel wall, ingrowth of vasa vasorum and recurrent dissections with subsequent growth of the aneurysm from the periphery. Treatment strategies of these diseases should take the underlying pathomechanism into consideration and include, depending on the presentation medical treatment, parent vessel occlusion, flow reversal or diversion, surgical options or a combined treatment protocol.

Trunkal intracranial aneurysms: dissecting and fusiform aneurysms

Aneurysms arising along the arterial trunk are uncommon and not well-characterized lesions in contrast to saccular aneurysms. According to pathological studies, most of spontaneous trunkal aneurysms are related to dissecting phenomena. On the basis of clinical presentation, dissecting aneurysms can be separated into acute or chronic lesions. Understanding of the underlying pathological mechanisms associated with these aneurysms is useful for planning appropriate treatment. This article reviews the etiopathogenesis, the angiographic aspects, and the endovascular treatment of dissecting aneurysms. Fusiform aneurysms and aneurysms in atherosclerotic disease also are discussed briefly.

Deficiencies in estrogen-mediated regulation of cerebrovascular homeostasis may contribute to an increased risk of cerebral aneurysm pathogenesis and rupture in menopausal and postmenopausal women

Despite the catastrophic consequence of ruptured intracranial aneurysms, very little is understood regarding their pathogenesis, and there are no reliable predictive markers for identifying at-risk individuals. Few studies have addressed the molecular pathological basis and mechanisms of intracranial aneurysm formation, growth, and rupture. The pathogenesis and rupture of cerebral aneurysms have been associated with inflammatory processes, and these have been implicated in the digestion and breakdown of vascular wall matrix. Epidemiological data indicate that the risk of cerebral aneurysm pathogenesis and rupture in women rises during and after menopause as compared to premenopausal women, and has been attributed to hormonal factors. Moreover, experimental evidence supports a role for estrogen in the modulation of each phase of the inflammatory response implicated in cerebral aneurysm pathogenesis and rupture. While the risk of aneurysm rupture in men also increases with age, this increased risk has been attributed to other recognized risk factors including cigarette smoking, use of alcohol, and history of hypertension, all of which are more common in men than women. We hypothesize, therefore, that decreases in both circulating estrogen levels and cerebrovascular estrogen receptor density may contribute to an increased risk of cerebral aneurysm pathogenesis and rupture in women during and after menopause. To test our hypothesis, experiments are needed to identify genes regulated by estrogen and to evaluate gene expression and intracellular mechanisms in cells/tissues exposed to varying concentrations and duration of treatment with estrogen, metabolites of estrogen, and selective estrogen receptor modulators (SERMs). Furthermore, it is not likely that the regulation of cerebrovascular homeostasis is due to the actions of estrogen alone, but rather the interplay of estrogen and other hormones and their associated receptor expression. The potential interactions of these hormones in the maintenance of normal cerebrovascular tone need to be elucidated. Additional studies are needed to define the role that estrogen and other sex hormones may play in the cerebrovascular circulation and the pathogenesis and rupture of cerebral aneurysms. Efforts directed at understanding the basic pathophysiological mechanisms of aneurysm pathogenesis and rupture promise to yield dividends that may have important therapeutic and clinical implications. The development of non-invasive tools such as molecular MRI for the detection of specific cells, molecular markers, and tissues may facilitate early diagnosis of initial pathophysiological changes that are undetectable by clinical examination or other diagnostic tools, and can also be used to evaluate the state of activity of cerebral aneurysm pathogenesis before, during, and after treatment.

Unruptured intracranial aneurysms: using evidence and outcomes to guide patient teaching

It is estimated that approximately 10 to 15 million Americans have intracranial aneurysms. Intracranial aneurysms are classified as either unruptured or ruptured. Advances in knowledge and technology are enhancing diagnosis, management, and outcomes associated with unruptured intracranial aneurysms. Optimal outcomes are achieved when aneurysms are treated before they rupture. If the aneurysm ruptures, the mortality rate ranges from 30% to 60%. A review of evidence regarding aneurysms, including the pathogenesis, risk factors, treatment options, and outcomes, is presented. Treatment options addressed include surgical clipping, endovascular coiling, or watchful waiting. Current evidence supports aggressive treatment for patients with previously ruptured aneurysms, large or symptomatic aneurysms, a family history of aneurysm rupture, a long life expectancy, and aneurysms demonstrating growth. Factors that favor watchful waiting include aneurysms that are small or located in the anterior circulation and in patients with a short life expectancy or comorbid medical conditions. Nurses are in an ideal position to use evidence and outcomes to provide accurate and current information on how to reduce the risks for rupture and evaluate treatment options.

Multiple Spontaneous Dissecting Aneurysms of the Anterior Cerebral and Vertebral Arteries-Case Report-

A 50-year-old woman presented with rare multiple dissecting aneurysms that appeared first in the anterior cerebral artery (ACA) and shortly afterwards in the vertebral artery (VA). She initially suffered sudden motor weakness in the left lower limb due to acute brain infarction. Angiography revealed diffuse string sign in the right ACA. Conservative treatment resulted in resolution of the deficits. Follow-up angiography performed 1 year later revealed recovery of the ACA stenosis. Fourteen days later, she complained of sudden headache and became comatose. Computed tomography showed diffuse subarachnoid hemorrhage. Angiography revealed a new right VA dissecting aneurysm involving the posterior inferior cerebellar artery (PICA). The orifice of the dissection was not apparent in the operative field and the dissection extended to the median. The patient underwent extracranial right VA ligation, clipping of the proximal PICA, and revascularization between the right occipital artery and distal PICA. Her postoperative course was uneventful and she was discharged without neurological deficits. VA dissecting aneurysms involving the PICA without evident orifice or extending over the median can be treated by extracranial ligation with clipping of the PICA, followed by revascularization.

Measurement of basilar artery bending and elongation by magnetic resonance cerebral angiography

Elongation and bending of the basilar artery are frequently observed in both normal and pathological subjects. However, their mechanism of generation remain unclear. In the present study, we measured basilar arteries in patients and normal subjects using magnetic resonance angiography (MRA) and estimated the relationships between these anatomical changes and some factors such as age, sex and vertebral artery dominance. A total of 510 subjects underwent MRA. Basilar artery length (BAL), bending length (BL), or side of bending of basilar artery was estimated on the plain images including the basilar artery in two groups with and without vertebral union. BAL was longer in males than in females (P = 0.0009) and correlated with age (P < 0.0001) in the population with vertebral union, while BL did not differ between genders and was not correlated with age in this population. Both BAL and BL were longer in subjects with vertebral artery dominance than in subjects with equivalent-sized vertebral arteries in the population with vertebral union (P < 0.0001 and P = 0.0005). No difference in the frequency of basilar artery bending was observed between males and females and no correlation was observed between the frequency of basilar artery bending and ages in subjects without vertebral artery union. A significant negative correlation between the side of bending of the basilar artery and dominant side of vertebral arteries was found for group of all patients (P < 0.0001). BAL growth may mainly depend on aging, and the presence of vertebral artery dominance may contribute to the growth of BAL while BL growth may depend on vertebral artery dominance mainly in the contralateral direction.

Peripheral and segmental spinal abnormalities of median and ulnar somatosensory evoked potentials in Hirayama's disease

OBJECTIVES

To investigate the origin of juvenile muscle atrophy of the upper limbs (Hirayama's disease, a type of cervical myelopathy of unknown origin).

SUBJECTS

Eight male patients were studied; data from 10 normal men were used as control.

METHODS

Median and ulnar nerve somatosensory evoked potentials (SEP) were recorded. Brachial plexus potentials at Erb's point (EP), dorsal horn responses (N13), and subcortical (P14) and cortical potentials (N20) were evaluated. Tibial nerve SEP and motor evoked potentials (MEP) were also recorded from scalp and spinal sites to assess posterior column and pyramidal tract conduction, respectively.

RESULTS

The most important SEP findings were: a very substantial attenuation of both the EP potentials and the N13 spinal responses; normal amplitude of the scalp N20; and normal latency of the individual peaks (EP-N9-N13-P14-N20). Although both nerves were involved, abnormalities in response to median nerve stimulation were more significant than those in response to ulnar nerve stimulation. There was little correlation between the degree of alterations observed and the clinical state. Latencies of both spinal and cortical potentials were normal following tibial nerve stimulation. The mean latency of cervical MEP and the central conduction time from the thenar eminence were slightly but significantly longer in patients than in controls.

CONCLUSIONS

The findings support the hypothesis that this disease, which is clinically defined as a focal spinal muscle atrophy of the upper limb, may also involve the sensory system; if traumatic injury caused by stretching plays a role in the pathogenesis, the damage cannot be confined to the anterior horn of the spinal cord.

Non-atherosclerotic fusiform cerebral aneurysms

BACKGROUND

Fusiform cerebral aneurysms are dilatations of the entire circumference of a segment of cerebral artery, usually considered due to atherosclerosis in adults. They are relatively thick-walled and elongated, causing neural compression or ischemia when discovered. We have noted a subset of fusiform cerebral aneurysms that vary from this common description.

PATIENTS

Out of a series of 472 intracranial aneurysms treated over 11 years, 11 patients between the ages 16 and 67 years (mean age 37) were identified who had discrete fusiform aneurysms unassociated with generalized cerebral atherosclerosis, connective tissue disorder or inflammation. Three presented with hemorrhage, six with neural compression by the aneurysm and two were discovered incidentally.

RESULTS

Nine aneurysms were located in the posterior circulation, the other two in the intracranial carotid artery. Their mean length and width were 16.3 and 11 mm, respectively. Three aneurysms contained thrombus. The eight aneurysms that were exposed surgically were partly or substantially thin-walled with normal appearing parent arteries. Eight were treated with proximal occlusion and three were circumferentially "wrapped". Parent artery occlusion caused one death and one mild disability and the remaining patients made good recoveries (follow-up 0.5 - 10 years).

CONCLUSIONS

There is a subset of cerebral aneurysms with discrete fusiform morphology, apparently unrelated to cerebral atherosclerosis or systemic connective tissue disease, thin-walled in part or whole, more common in the vertebrobasilar system, and possessing a risk of rupture. Treatments currently available include proximal occlusion or aneurysm wrapping", different approaches than neck-clipping or endovascular coiling of side-wall saccular cerebral aneurysms that leave the parent artery intact.