The aneurysmal wall. The key to a subclassification of intracranial arterial aneurysm vasculopathies?

SUMMARY

The pathogenesis of intracranial arterial aneurysms (AA) has been debated for many years and still remains unclear, although these entities might pose life-threatening risks to the patient and understanding the disease is of utmost importance for choosing treatment concepts. Apart from the "classical" berry-type aneurysm, there are different other types of intracranial AA such as infectious, dissecting or giant, partially thrombosed aneurysms. From the clinician's perspective, the hypothesis that some of these intracranial aneurysms might be due to abluminal factors has been put forward for many years. Alterations of the vessel wall, either due to luminal or abluminal factors may be employed for an etiological classification of aneurysmal vasculopathies as will be discussed in this article. Moreover, regarding certain aneurysmal vasculopathies as an abluminal disease might alter current therapeutic strategies since therapy should not only aim at the intraluminal repair of the artery but may also target the vessel wall.

Imaging Findings of a Patient with Incomplete Phenotypical Expression of the PHACES Syndrome

SUMMARY

We present imaging findings of a patient with an incomplete form of the PHACES syndrome with dolichosegmental intracranial arteries as the predominant component, and discuss the etiopathological and clinical significance of this finding.

Extracranial vertebral artery involvement in neurofibromatosis type I. Report of four cases and literature review

SUMMARY

Neurofibromatosis type 1 (NF-1) is one of the most common inherited diseases and as an autosomal dominant genetic disorder results from NF-1 gene mutation with 100% penetration and wide phenotypic variability. The disease can involve a wide variety of tissues derived from all three embryonic layers. NF-1 vasculopathy has been described primarily in peripheral arteries, but arteries supplying the CNS may also be involved. Of those, extracranial vertebral involvement is the commonest and most important. A series of four patients with NF-1 and vascular disease of the vertebral artery is described with a review of the pathophysiology, vascular phenotypes, their management and the pertinent literature.

Segmental unfused basilar artery with kissing aneurysms: report of three cases and literature review

Basilar artery "fenestration" is the result of a failed fusion of the bilateral longitudinal neural arteries and can be associated with a saccular aneurysm, which typically arises at the proximal juncture of the unfused segment. "Kissing" aneurysms at this site, i.e. two aneurysms arising from the proximal junction of the unfused segment of the basilar artery pointing anteriorly and posteriorly are reported to be exceedingly rare. We present three patients with this rare condition, all of them being treated by endovascular techniques.

Spontaneous intracerebral hemorrhage caused by an unusual association of developmental venous anomaly and arteriovenous malformation

SUMMARY

We describe three patients who presented with spontaneous intracerebral hemorrhage resulting from the close association of developmental venous anomaly (DVA) and arteriovenous malformation (AVM). Angioarchitecturally, either the DVA formed the draining pathway for the AVM or they shared a common venous channel. The AVMs were treated by targeted embolization and the DVAs were carefully preserved. It is suggested that the unusual association of an AVM with the less flexible DVA was the cause of hemorrhage.

Spontaneous mirror dissections of cervicocephalic arteries. Pathomechanical considerations

SUMMARY

While so-called twin or mirror aneurysms constitute an established subgroup of multiple aneurysms, simultaneous spontaneous mirror dissections of cervicocephalic artery have not yet been reported as a particular entity. Among the patients treated at our institution since 1989, we identified 74 patients with spontaneous, nontraumatic dissections. Six of these cases presented with simultaneous bilateral dissections and four of the six patients had mirror dissections. Acute or chronic headache was present in all four cases. Additional clinical presentations consisted of impaired consciousness, cranial nerve palsy, and tinnitus. Angiography revealed irregular stenosis, dilatation or aneurysms located in the cervical ICA (internal carotid artery), VA (vertebral artery), or MCA (middle cerebral artery) without evident location bias. Although mirror dissections seems to be an exceptional finding, they may shed light on the vulnerability of different arterial segments to specific diseases. Similar to arterial aneurysm formation, pathogenesis of mirror dissection may involve an underlying "shared defect" in the endothelial cells, since these cells demonstrate a bilateral distribution during embryological development. This particular distribution therefore also provides a chronicle trail of the first trigger striking during embryonic development and demonstrates the segmental vulnerability to highly specific triggers.

Hereditary hemorrhagic telangiectasia in children: endovascular treatment of neurovascular malformations: results in 31 patients

Hereditary hemorrhagic telangiectasia (HHT) is a heterogeneous disease that can present with a variety of clinical manifestations. The neurovascular complications of this disease, especially in children, may be potentially devastating. The purpose of this article was to review the therapeutic results of endovascular treatment of neurovascular malformations in children. A total of 31 patients under the age of 16 were included in this retrospective analysis. All children were treated in a single center. Twenty children presented with 28 arteriovenous (AV) fistulae, including seven children with spinal AV fistulae and 14 children with cerebral AV fistulae (one child had both a spinal and cerebral fistulae). Eleven children had small nidus-type AV malformations. All embolizations were performed employing superselective glue injection. Follow-up ranged between 3 and 168 months (mean 66 months). A total of 115 feeding vessels were embolized in 81 single sessions, resulting in a mean overall occlusion rate of the malformation of 77.4% (ranging from 30 to 100%). Two of 31 patients (6.5%) died as a direct complication of the embolization procedure; two patients (6.5%) had a persistent new neurological deficit; eight patients (26.7%) were clinically unchanged following the procedure; in 13 patients (41.9%) an amelioration of symptoms but no cure could be achieved; and six patients (19.4%) were completely asymptomatic following the endovascular procedure. In the surviving patients morphological complete occlusion was possible in twelve patients (38.7%); therapy is still not completed in six patients. Since the natural history of neurovascular manifestations of HHT in children is associated with high morbidity and mortality, therapeutic intervention is mandatory. In most instances a morphological target can be identified; therefore, even partial and staged treatment can be performed. Our results demonstrate that in 27/31 patients these targeted interventions resulted in stabilizing the disease, ameliorating the symptoms or even complete resolution. The endovascular approach employing glue as the embolizing agent represents a safe and efficient way to control the neurovascular phenotypes of HHT.

Neurovascular phenotypes in hereditary haemorrhagic telangiectasia patients according to age. Review of 50 consecutive patients aged 1 day-60 years

Hereditary haemorrhagic telangiectasia (HHT) is inherited as an autosomal dominant trait with varying penetrance and expressivity. Some of the most devastating consequences of this disease result from cerebral vascular malformations that manifest themselves in either arteriovenous fistulae (AVF), small nidus-type arteriovenous malformations (AVM) or micro-AVMs with a nidus less than 1 cm in size. The purpose of this study was to compare the phenotypes of CNS-manifestations of HHT with the age of the patient. The charts and angiographic films of 50 patients diagnosed with HHT according to the Curaçao criteria were retrospectively evaluated concerning age of onset of symptoms, or, if not applicable of first consultation. The files were reviewed for clinical presentation, family and personal history, while the patients' angiograms were analysed with respect to the number of lesions (single and multiple), the location (superficial supratentorial, deep supratentorial, infratentorial, and spinal), and type of lesion (fistulous AVM, nidus-type AVM, and micro-AVM). A total of 75 central nervous system manifestations of HHT were found. Lesions included seven spinal cord AVFs that were all present in the paediatric age group (mean age: 2.2 years), 34 cerebral AV fistulae, all but two affected patients were less than 6 years (mean age 3.0). Sixteen nidus type AVMs (mean age: 23.1 years) and 18 micro-AVMs (mean age: 31.8 years) were found. HHT displays an age-related penetrance of clinical manifestations. Since members of the same family can present with completely different phenotypes of this disease there seems to be no relationship between the type of mutation and the phenotype of the disease. Since there seems to be a continuum of vascular abnormalities (from large fistulous areas to small AVMs and micro-AVMs) associated with HHT, the most likely determinating factor of the HHT phenotype is the timing of the revealing event in relation to the maturity of the vessel. Presumably, the trigger of the quiescent genetical abnormality transforms a "dormant" disease into a morphologically and therefore clinically detectable one by impairing a specific vessel segment at a specific (more or less vulnerable) period of time. The nature of this triggering event is, however, as of yet unclear.

Hereditary haemorrhagic telangiectasia in children. Endovascular treatment of neurovascular malformations. Results in 31 patients

SUMMARY

Hereditary haemorrhagic telangiectasia (HHT) is a heterogeneous disease that may present with different clinical phenotypes and different clinical expressions. Concerning the neurovascular expressions of this disease, the paediatric age group in particular presents with potentially devastating symptomatic phenotypes. The purpose of this article was to review the therapeutic results of endovascular treatment of neurovascular malformations in children. A total of 31 children under the age of 16 were included in this retrospective analysis. All children were treated in a single centre. Twenty children presented with 28 arteriovenous (AV) fistulae including seven children with spinal AV fistulae and 14 children with cerebral AV fistulae (one child had both a spinal and cerebral fistulae). Eleven children had small nidus type AV malformations. All embolizations were performed in a single centre employing superselective glue injection. Follow-up ranged between three and 168 months (mean: 66 months) A total of 115 feeding vessels were embolized in 81 single sessions resulting in a mean overall occlusion rate of the malformation of 77.4% (ranging from 30 to 100%). Two of 30 patients (6.5%) died as a direct complication of the embolization procedure, two patients (6.5%) had a persistent new neurological deficit, eight patients (26.7%) were clinically unchanged following the procedure. In 11 patients (36.7%) an amelioration of symptoms but no cure could be achieved, six patients (20%) were completely asymptomatic following the endovascular procedure. In the surviving patients morphological complete occlusion was possible in twelve patients (38%), therapy is still not complete in six patients. Since the natural history of neurovascular manifestations of HHT in children is associated with a high morbidity and mortality, therapeutic intervention is mandatory. In most instances a morphological target can be identified, therefore even partial and staged treatment can be performed. Our results demonstrate that in 27/31 patients these targeted interventions resulted in stabilizing the disease, ameliorating the symptoms or even in curing the patient. The endovascular approach employing glue as the embolizing agent represents therefore a safe and efficient way to control the neurovascular phenotypes of HHT.

PHACES syndrome: a review of eight previously unreported cases with late arterial occlusions

PHACE and PHACES are acronyms for a syndrome of variable expression comprising posterior cranial fossa malformations, facial haemangiomas, arterial anomalies, aortic coarctation and other cardiac disorders, ocular abnormalities and stenotic arterial disease. We review five girls and three boys aged 1 month-14 years with disorders from this spectrum. Six had large facial haemangiomas but recent reports suggest that small haemangiomas may occur; hence our inclusion of two possible cases. We also focus on the recently recognised feature of progressive intracranial arterial occlusions, present in four of our patients, later than previously recognised, from 4 to 14 years of age. We suggest that many elements of this disorder could reflect an abnormality of cell proliferation and apoptosis.

Craniofacial arteriovenous metameric syndrome (CAMS) 3--a transitional pattern between CAM 1 and 2 and spinal arteriovenous metameric syndromes

We report a rare case of craniofacial arteriovenous metameric syndrome (CAMS) 3 arteriovenous malformations of the mandible, left VIII nerve and petrous bone. The patient, a 19-year-old girl, presented with profuse gingival bleeding during a dental procedure and we diagnosed CAMS 3 during a pre-embolisation angiogram. The distribution of the vascular lesions suggests that CAMS 3 is intermediate CAMS 1 and 2 and spinal arteriovenous metameric syndrome (SAMS).

Concomitant conus medullaris arteriovenous malformation and sacral dural arteriovenous fistula of the filum terminale

SUMMARY

A patient with a spinal intradural arteriovenous malformation (AVM) at the conus medullaris concomitant with a sacral dural arteriovenous fistula (AVF) of the filum terminale is reported. A 44-year-old-male presentied with bilateral leg weakness and urinary incontinence for several months. Spinal angiography demonstrated two lesions: one was spinal intradural AVM at the conus medullaris supplied by the anterior spinal artery; the other was sacral dural AVF of the filum terminale supplied by the middle sacral artery. Although multifocal spinal cord AVMs have been reported, this is the first case report of two different types of vascular malformations coexisting in one patient. The arterial supply of the dural AVF of the filum by the middle sacral artery is also first demonstrated in the literature. The patient was treated successfully by surgical approach for both lesions in the same operation.

Intracranial haemorrhage within the first two years of life

BACKGROUND

Spontaneous intracranial haemorrhage is not common in infants, with differences from adults in both aetiology and severity. The infantile CNS is more vulnerable because of incomplete hydrovenous maturation. We analyzed infantile intracranial haemorrhage mainly caused by structural brain lesions and discuss specific aetiologies with regard to haemodynamic characteristics.

SUBJECTS AND METHODS

We reviewed 20 infants less than 2 years of age from a total of 328 neonates and infants with intracranial vascular lesions seen in our institution since 1985. Associated or causative lesions were arteriovenous malformation (AVM) in 6, dural sinus malformation (DSM) in 4, arteriovenous fistula (AVF) in 3, aneurysm in 2, developmental venous anomaly (DVA) in 1, vein of Galen malformation (VGAM) in 1, and others in 3. The locations of haematomas were intracerebral (ICH) in 8, combined ICH and intraventricular haemorrhage (IVH) in 5, IVH alone in 5, subarachnoid haemorrhage (SAH) in 1, and combined SDH and ICH in 1.

FINDINGS

Three patterns of haemorrhage were noted in high-flow vascular lesions such as AVM or AVF (n=9); haemorrhage at the site of nidus or fistula corresponding to nidal pseudoaneurysm in 4, regional venous hypertension with pial venous reflux in 3, global venous infarction causing multifocal haemorrhage in distant brain areas in 2. Aneurysmal bleeds were caused by dissecting aneurysms at the level of dural penetration of cranial vessels. One infant had haemorrhage near a DVA without evidence of cavernous malformation suggesting the possibility of venous ischaemia. IVH was associated with shunt operations in 4 infants with DSM, and SDH followed by ICH in a infant with VGAM.

INTERPRETATION

Spontaneous intracranial haemorrhage in infants and neonates is rare; it is associated with specific lesions which show some differences from their adult counterparts. The vein-related causes of hemorrhage are largely the pathophysiologic characteristics in this age group. Absence of hemorrhage in VGAM is remarkable in addition to occurrence of most hemorrhages after shunting.

Segmental identity and vulnerability in cerebral arteries

SUMMARY

Clinical experience shows that certain diseases involve specific areas of the vascular tree and remarkably spare others. Topographic differences in the vascular environment already suggest a regional specificity of the vascular anatomy. The biological grounds of such regional differences, although unknown, can account for the specificity of biological responses to stimuli. Such segmental specificities are beyond morphological analysis. They create an invisible discontinuity in an apparently homogenous anatomical, histological and haemodynamic system.We call this property segmental identity and thus vulnerability. Most of this identity is established during development and is preserved throughout life; its expression, however,may vary over time according to various stresses and create various clinical phenotypes. The memory of the evolutionary steps and their chronology is imprinted on the arterial anatomy and thus potentially readable. One can postulate that since the age of each arterial segment is different, its resistance to time and stimuli is most likely variable. The vulnerability of these segments cannot be permanent both in a qualitative and quantitative way. Some genetic functions only seem to be active during a short period of time: during vasculogenesis for example. Therefore either the trigger is always active and the target vulnerability window of the cells time-limited, or the target is permanently exposed and the trigger agent can either be exogenous and rare, or most of the time inactive or inactivated.

Endovascular Management of a Traumatic Basilar Tip Aneurysm following Endoscopic Ventriculostomy in a Child

SUMMARY

We report the case of four year nine month old girl that presented a basilar tip iatrogenic arterial aneurysm following ventriculostomy. Despite being a false aneurysm the lesion was successfully coiled two years later.

Aneurysmal disease in children. Review of 20 cases with intracranial arterial localisations

SUMMARY

Twenty children (13 males, 7 females), referred to our group with non traumatic intracranial aneurysms between 1978 and January 1997, were included in this study. Their angiograms were reviewed to assess number, location, type of aneurysms and evolution before and after treatment. Their ages ranged from 1 month to 15 years. Seven patients (35%) presented with subarachnoid haemorrhage (SAH). Eleven patients (55%) presented with focal neurological deficits or seizures: epileptic seizures occurred in five patients, neurologic deficits or focal symptoms due to mass effect occurred in six. Total number of diagnosed intracranial aneurysms was 24. The most common sites involved were internal carotid (37%) and vertebrobasilar (32%) systems. The aetiology of the aneurysms was infective in four patients and unknown in the remaining 16 patients (80%). Endovascular treatment was successful in seven patients (37%). Three patients (15%) were surgically treated. Seven patients (35%) were conservatively treated. Two patients (10%) had spontaneous thrombosis of the aneurysm. SAH was more frequent in males, and never occurred in children under five years old. Frequent presentations such as focal symptoms or mass effect and less prevalence of aneurysm rupture are probably due to the high prevalence of large or giant aneurysms (25%) in our series. In conclusion, radiological findings and the natural history of symptomatic arterial aneurysms in children are clearly different from those in adults. Probably pathogenetic factors and aetiology are also different. Shear stresses, haemodynamic and hormonal factors do not appear to be dominant to reveal such defects, though their correction favours repair. Since repair is frequent, conservative treatment has a major role in their aneurysm management.

Urgent and emergent embolization of lesions of the head and neck in children: indications and results

Indications for and results and complications of embolization of lesions of the head and neck were analyzed retrospectively. The procedures were performed since 1980 on an emergent or urgent basis in 30 infants and children by an experienced interventional neuroradiologist in Bicetre, France. Indications for embolization included hemorrhage, occular occlusion, respiratory obstruction, CNS complications or potential complications, interference with nutrition, and functional impairment related to the effect of the lesion on the developing facial skeleton and teeth. The specific lesions included seven hemangiomas (palpebral, subglottic, and nasal) and 20 vascular malformations (maxillofacial, auricular, dural, cerebral [including three vein of Galen malformations] and spinomedullary). Embolization was efficacious in 28 of 30 patients. Hemangiomas (potentially involutive tumors) responded dramatically with arrest of the proliferative phase and shrinking of the mass. Combined hemovascular lymphatic malformations (hemolymphangiomas) of the tongue demonstrated a variable decrease in size. High-flow evolutive arteriovenous malformations involving the teeth and dura were controlled but required multiple embolizations. One infant with a vein of Galen arteriovenous malformation died. Three local complications occurred in two patients. No cerebral ischemic or femoral artery complications occurred.

Direct spinal arteriovenous fistula: a new type of spinal AVM. Case report

A patient presenting with progressive paraparesis was found to have a spinal arteriovenous fistula at the T3-4 vertebral level. The lesion consisted of a direct communication of the anterior spinal artery with a very distended venous varix that drained mostly superiorly to the posterior fossa and simulated a posterior fossa arteriovenous malformation (AVM) on vertebral angiography. The patient was treated by surgical ligation of the fistula through an anterior transthoracic approach. He deteriorated abruptly on the 4th postoperative day, probably because of retrograde thrombosis of the enlarged anterior spinal artery. Over the next few months, he improved to the point of being able to walk with crutches. He has also regained sphincter control. The different types of spinal AVM's are reviewed. Our case does not fit into any of these groups. A new category, Type IV, is proposed to designate direct arteriovenous fistulas involving the intrinsic arterial supply of the spinal cord.