Karel G. ter Brugge

The Natural History and Predictive Features of Hemorrhage From Brain Arteriovenous Malformations

Background and Purpose— Patients harboring brain arteriovenous malformations (bAVMs) are at a lifelong risk for hemorrhagic strokes, but the natural history is poorly understood. We examined the impact of demographic and angiographic features on the likelihood of future hemorrhage. Methods— A prospectively accrued database of bAVM patients maintained at the Toronto Western Hospital was analyzed; 678 consecutive, prospectively enrolled bAVM patients were followed for 1931.7 patient-years. The rate of hemorrhage over long-term follow-up was recorded. The impact of baseline clinical and radiographic features and partial treatment on time to hemorrhage were analyzed using survival analysis. Neurological outcome after hemorrhage was assessed using the Glasgow Outcome Score. Results— Hemorrhage rates were 4.61% per year for the entire cohort (n=678), 7.48% per year for bAVMs with initial hemorrhagic presentation (n=258), 4.16% per year for initial seizure presentation (n=260), 3.99% per year for patients not harboring aneurysms (n=556), 6.93% per year for patients with associated aneurysms (n=122), and 5.42% per year for bAVMs with deep venous drainage (n=365). Hemorrhagic presentation was a significant independent predictor of future hemorrhage (HR, 2.15; P<0.01), whereas associated aneurysms (HR, 1.59; P=0.07) and deep venous drainage (HR, 1.59; P=0.07) showed a trend toward significance. Hemorrhage risk was unchanged in patients who underwent partial arteriovenous malformation embolization (n=211; HR, 0.875; P=0.32). Conclusion— Brain arteriovenous malformations presenting with hemorrhage, with deep venous drainage, or associated aneurysms have ≈2-fold greater likelihood of a future hemorrhage. Partial treatment by embolization does not alter these risks. This natural history should be taken into account in the treatment strategy.

Management of intracranial dural arteriovenous shunts in adults

Dural arteriovenous shunts are abnormal arteriovenous communications within the dura. They are thought to be an acquired condition in adults and can present with a variety of clinical features, ranging from benign bruits to intracranial hemorrhage and neurological deficits. The presentation and natural history of these shunts is largely determined by the pattern of venous drainage. Knowledge of natural history and careful study of the angioarchitexture by angiography is therefore mandatory for correct management of these lesions. In this review, principles of management in adults and the various factors that influence treatment decisions are discussed, with a focus on endovascular therapy. Retrograde leptomeningeal or cortical venous drainage has a strong correlation with adverse clinical events and the requirement for aggressive management in this situation is highlighted. Indications for endovascular treatment, therapeutic goals, approaches and techniques are reviewed. The role of surgical treatment is also briefly discussed.

Acute Subdural Hematoma from Ruptured Posterior Communicating Artery Aneurysm

Acute spontaneous subdural hematoma is infrequent in association with rupture of intracranial saccular aneurysm. In the majority of cases, aneurysms of the middle cerebral artery along the convexity or of the anterior cerebral artery along the interhemispheric fissure are found to be the culprits. We present two recent cases of internal carotid-posterior communicating artery aneurysms causing acute subdural hematoma with little or no subarachnoid hemorrhage and discuss the possible mechanisms for this occurrence.

Impact of individual intracranial arterial aneurysm morphology on initial obliteration and recurrence rates of endovascular treatments: a multivariate analysis

OBJECT The goal was to investigate whether morphological features of aneurysms can be identified that determine initial success and recurrence rates of coiled aneurysms of the basilar artery tip, the posterior communicating artery (PCoA), and the anterior communicating artery. METHODS The authors evaluated 202 aneurysms in connection with their pretreatment morphological features including size, neck-to-dome ratio, angulation of the aneurysm in relation to the parent artery, orientation of the aneurysm dome, and associated anatomical variations. The mean follow-up was 19 months (range 6-96 months) after endovascular coil occlusion. Using multivariate logistic regression, probabilities for initial complete occlusion and long-term stability of the treatment were calculated. RESULTS Recanalization occurred in 49 of 202 cases. Favorable factors for long-term stability included small aneurysms with small necks. However, additional factors related to local hemodynamic forces could be identified for the different aneurysm locations, which may influence initial success rates and long-term stability of aneurysm treatment with endovascular coiling. These factors were a medial dome orientation and a symmetrical disposition of both A(1) segments (for the anterior communicating artery), a posteroinferior dome orientation and a small-size PCoA (for the PCoA), and a cranial symmetrical fusion (for the basilar artery tip). CONCLUSIONS A detailed pretreatment analysis of morphological features of aneurysms may help to determine those aneurysms that are more prone to recurrence, which could add to the treatment decision and the follow-up algorithm.

Spinal and Spinal Cord Arteries and Veins

The vascular anatomy of the spine and spinal cord has been well known since the end of the nineteenth century. Most recently, angiographic investigations have added to this body of knowledge (Chiras 1979, 1985; Crock 1977; Di Chiro 1973; Djindjian 1970; Dommisse 1975; Doppman 1969; In the maxillofacial area beside the cranium few bony barriers exist, although the mandible and the maxillary bone have vascular foramina, fissures, and canals. The only true barrier in this area is represented by the muscles of mastication: the temporal, pterygoid, and masseter muscles. The arteries run on the surface of these muscles, and local collateral circulation sometimes takes a wandering course, as the vessels skirt around the muscles (Fig. 1.21). In the facial region, cutaneous muscles do not behave as a comparable restrictive barrier; local collateral circulation through subcutaneous or submucosal arteries is seldom tortuous, even after increased blood flow.

Clinical course of untreated cerebral cavernous malformations: a meta-analysis of individual patient data

Summary Background Cerebral cavernous malformations (CCMs) can cause symptomatic intracranial haemorrhage (ICH), but the estimated risks are imprecise and predictors remain uncertain. We aimed to obtain precise estimates and predictors of the risk of ICH during untreated follow-up in an individual patient data meta-analysis. Methods We invited investigators of published cohorts of people aged at least 16 years, identified by a systematic review of Ovid MEDLINE and Embase from inception to April 30, 2015, to provide individual patient data on clinical course from CCM diagnosis until first CCM treatment or last available follow-up. We used survival analysis to estimate the 5-year risk of symptomatic ICH due to CCMs (primary outcome), multivariable Cox regression to identify baseline predictors of outcome, and random-effects models to pool estimates in a meta-analysis. Findings Among 1620 people in seven cohorts from six studies, 204 experienced ICH during 5197 person-years of follow-up (Kaplan-Meier estimated 5-year risk 15·8%, 95% CI 13·7–17·9). The primary outcome of ICH within 5 years of CCM diagnosis was associated with clinical presentation with ICH or new focal neurological deficit (FND) without brain imaging evidence of recent haemorrhage versus other modes of presentation (hazard ratio 5·6, 95% CI 3·2–9·7) and with brainstem CCM location versus other locations (4·4, 2·3–8·6), but age, sex, and CCM multiplicity did not add independent prognostic information. The 5-year estimated risk of ICH during untreated follow-up was 3·8% (95% CI 2·1–5·5) for 718 people with non-brainstem CCM presenting without ICH or FND, 8·0% (0·1–15·9) for 80 people with brainstem CCM presenting without ICH or FND, 18·4% (13·3–23·5) for 327 people with non-brainstem CCM presenting with ICH or FND, and 30·8% (26·3–35·2) for 495 people with brainstem CCM presenting with ICH or FND. Interpretation Mode of clinical presentation and CCM location are independently associated with ICH within 5 years of CCM diagnosis. These findings can inform decisions about CCM treatment. Funding UK Medical Research Council, Chief Scientist Office of the Scottish Government, and UK Stroke Association.

Severely impaired cerebrovascular reserve in patients with cerebral proliferative angiopathy

OBJECT Cerebral proliferative angiopathy (CPA) has been morphologically distinguished from classically appearing brain arteriovenous malformations (AVMs) by exhibition of functional brain parenchyma that is intermingled with abnormal vascular channels. The presence of oligemia in this intralesional brain tissue may suggest ischemia, which is not detected in classic brain AVMs. The authors hypothesized that patients with CPA would exhibit a greater impairment of cerebrovascular reserve in neuronal tissue surrounding the true nidus compared with those with brain AVMs. METHODS Four patients with CPA, 10 patients with brain AVMs and seizures, and 12 young healthy individuals were studied. The 4 patients with CPA underwent blood oxygen level-dependent MR imaging examinations while applying normoxic step changes in end-tidal CO(2) to obtain quantitative cerebrovascular reactivity measurements. RESULTS Patients with a CPA lesion exhibited severely impaired perilesional cerebrovascular reserve in comparison with patients with brain AVMs and seizures (0.10 ± 0.03 vs 0.16 ± 0.03, respectively; p < 0.05), and young healthy individuals (0.10 ± 0.03 vs 0.21 ± 0.06, respectively; p < 0.01). CONCLUSIONS This study demonstrated severely impaired cerebrovascular reserve in the perilesional brain tissue surrounding the abnormal vessels of patients with CPA. This finding may provide an additional means to distinguish CPA from classic brain AVMs.

Malformations of the Fetal Dural Sinuses

BACKGROUND Dural sinus malformation (DSM) is a term used to describe congenital vascular malformations characterized by massive dilation of one or more dural sinuses: these dilatations are typically associated with arteriovenous shunts. Such malformations can present antenatally but their early natural history and anatomy is poorly defined. METHODS We reviewed five years of autopsy experience and retrieved three primary vascular malformations of the fetal dural sinuses with ultrasound, magnetic resonance imaging (MRI) and post-mortem correlation. RESULTS Fetal ultrasound and MRI obtained between 19 and 23 weeks gestational age demonstrated in all cases dilation of the dural sinuses. In two cases vascular thromboses were present in either the dilated dural sinus (one of three) or the associated arteriovenous fistula (one of three). All cases were autopsied at 22-23 weeks gestational age. In one there was imaging and autopsy evidence of remodeling of the dural sinuses associated with a pial arteriovenous fistula. In two cases, no arteriovenous malformation was identified on initial imaging, but only became evident at autopsy. One case showed morphological overlap with vein of Galen aneurysmal malformation, with a midline arteriovenous shunt and vein of Galen ectasia. The other demonstrated a perisylvian dural arteriovenous fistula. CONCLUSION In utero thrombosis of feeding vascular malformations or of the dural sinus malformation may be prominent. The early in utero developmental trajectory of dural sinus malformation (DSM) is poorly defined and deserves further study.

Spinal Arteriovenous Malformations

Because of the role of the neural crest and the mesoderm in the development of the segmental vascularization,extracranial branchial and para-spinal arteriovenous fistulae (AVFs) are similar in nature. Although they are located in different anatomical areas,the fistulae are fed by arteries supplying the craniocervical junction (the maxillary, the ascending pharyngeal artery, the occipital artery and the thyro-and costocervical arteries). The internal carotid artery (ICA) in its first cervical segment can also be included in this group, as it corresponds to the third aortic arch. The vertebral arteries are intersegmental channels that bridge and link three to eight cervical segmental arteries (Vol.1). The arteriovenous shunts (AVSs)supplied by the vertebral arteries should also be considered as segmental. We can therefore include vertebral artery-to-vertebral vein fistulae or vertebro-vertebral AVFs (VVAVFs)in the group of extracranial and paraspinal AVFs (parachordal, following the notochord).

Spinal Dural Arteriovenous Fistulae

As opposed to the so-called congenital arteriovenous malformations (AVMs) involving cord and paraspinal structures, spinal dural arteriovenous fistulae (SDAVFs) are acquired shunts located within or adjacent to dura along the spinal canal. They are by far the most frequent arteriovenous shunt (AVS) that occurs in older adults. They usually present after the fourth or fifth decade of life, with an 85% (5:1) male predominance (Tables 12.1, 12.2).The reason for this male predominance at the spinal level is not known,and this dominance is reversed in dural and osteodural AVSs at the skull base and sphenoid level, where there is a female pre-dominance. The location of the fistula has been reported throughout the spinal canal, from the sacrum to the level of the foramen magnum. The venous drainage may be very extensive and reach the intracranial dural sinuses even if the shunt is at the sacral level (Fig. 12.1) or conversely reach the thoracic perimedullary venous plexus level from an intracranial shunt.