Morbidity of intracranial hemorrhage in patients with cerebral arteriovenous malformation

How to deal with incompletely treated AVMs: experience of 67 cases and review of the literature

INTRODUCTION

Despite the availability of multimodal treatment options, some arteriovenous malformations remain difficult to treat, either for intrinsic reasons at initial presentation or for reasons evolving during the course of treatment. Frequently, such cases can be easily resolved with further therapy, but some become a continuously growing treatment dilemma while exhausting dwindling therapeutic options.

PATIENTS AND METHODS

A retrospective analysis was performed to identify patients with cerebral AVM who were treated unsuccessfully. Treatment was termed "not successful" if (1) postoperative angiography showed a residual AVM or missing flow reduction after palliative embolization, (2) therapy was associated with a substantial deterioration of existing neurological deficits or death, or (3) rebleeding from residual AVM occurred after therapy. Special interest was focused on the angiographic appearance of residual AVMs, their characteristic features, and their follow-up regarding second and third therapies.

RESULTS

According to these criteria we identified 46 internal patients from our own series of 474 patients and 21 external patients who were referred from other institutions or sought a second opinion after incomplete treatment elsewhere. Out of those 67 cases, 50 patients (74.6%) were diagnosed with a residual AVM. Eleven patients (16.4%) experienced a deterioration of their clinical condition under therapy. Six patients did not show a flow reduction after palliative embolization. Twenty-five of the 67 patients were readmitted because of an ICH, either originating from an AVM residual or under palliative embolization. Thus, an increased risk of re-hemorrhage was found for palliative embolization (n = 16) in partially treated lesions (n = 10) and in patients with AVM grade IV and V located in eloquent regions (n = 22). In dealing with residual AVMs, microsurgical resection alone or in combination was found to be the most efficient therapeutic option, being successful in 58.9% of cases.

CONCLUSION

An estimated 10% of AVM treatments may fail because of inadequate selection of either patients or management. Besides, for thorough decision-making, angiographic follow-up in all AVM patients is mandatory to allow an early identification of patients with an incompletely treated AVM requiring a second attempt. Major attention should be focused especially on high-risk subgroups with complex AVMs, partially treated AVMs, or those treated by only a palliative regimen.

To glue or not to glue? That is the question!!!

The purpose of Clinical Problem Solving manuscripts is to present management challenges in an attempt to give practicing neurosurgeons insight into how field leaders address these dilemmas. This illustration is accompanied by a brief review of the literature on the topic. We describe the case of a patient who presented with recurrent headaches resulting from a nondominant hemisphere parietal arteriovenous malformation. Challenges in prognosis, treatment, and complication management are discussed.

The ARUBA trial: current status, future hopes

BACKGROUND AND PURPOSE

Report on the status of an on-going National Institutes of Neurological Disorders and Stroke (NINDS)-supported clinical trial of management of unbled brain arteriovenous malformations.

SUMMARY OF REVIEW

Begun in April 2007 with 3 centers, the trial has grown to 65 centers, and has randomized 124 patients through mid-June 2010 en route to the planned 400. The current literature continues to support the rationale for the trial.

CONCLUSIONS

ARUBA is steadily approaching its monthly randomization goals and has already reached the number needed to test the maximum published interventional complication rates against the minimum hemorrhage rates for natural history.

Endovascular embolization for deep Basal Ganglia arteriovenous malformations

We report our experience with basal ganglia AVM embolization and clinical outcomes after embolization. We retrospectively evaluated consecutive 15 patients with AVMs in the basal ganglia with respect to the endovascular treatment of these lesions. Treatment consisted of embolization and radiosurgery in combination. The angiographic follow-up after the last management was 24-36 months (mean 27 months). Clinical follow-up monitoring (range, 24-120 months, mean 76 months) was measured by the Modified Rankin Scale (mRS). The 15 patients studied had a mean age of 25.1 years at diagnosis, and 33.3% were male. Intracranial hemorrhage (ICH) was the event leading to clinical detection in eight patients (53.3%), and 85.5% of these patients were left with hemiparesis. At presentation, eight (53.3%) patients bled a total of 11 times. Twenty-four embolization procedures (16 pedicles embolized) were performed in 15 patients with embolization as the adjunct to radiosurgery. There were three clinically significant complications. Excellent or good outcomes (mRS≤2) were observed in 13 (86.7%) patients. Unfavorable outcomes (mRS≤2) were 13.3% at follow-up, without mortality. Seven (46.7%) patients had complete AVM obliteration at follow-up. The risk of incurring a neurological deficit with basal ganglia AVM is high. Treatment of these patients is endovascular embolization with a combination of radiosurgery to prevent neurological injury from a spontaneous ICH.

Differentiating Components of Cerebral Arteriovenous Malformations Using T1-Weighted Gradient Recall Echo MR Imaging

Cerebral arteriovenous malformation (AVM) typically shows signal void on conventional MR images, making differentiation of each component difficult. We analyzed the MR signal intensity of AVM components on T1-weighted gradient recalled echo pulse sequence images. We retrospectively studied 29 patients with AVM between 2006 and 2008. Patients were excluded if they had 1) intracranial hemorrhage, 2) previous intervention for AVM. All patients underwent MR study on a 3T system (Magentom TIM Trio, Siemens). Pulse sequences included T1-weighted gradient recalled echo (T1GRE), T2-weighted (T2), time-of-flight (TOF), and contrast-enhanced T1-weighted (cT1) images. Digital subtracted angiography (DSA) was performed in all patients as a diagnostic standard. Signal intensity of each AVM component was recorded and compared between pulse sequences. Nine patients were studied (five men; mean age 39.1 years) and nine AVM were identified (mean size, 3.9 cm). Three different signal intensities (hypo-, iso-, and hyper-intensity) were observed in all nine patients on T1GRE. Only one signal intensity was seen on T2 (flow void) and cT1 images (hyperintensity) in nine patients. Two different signal intensities were observed in all seven patients with TOF images. The T1GRE image showed the largest number of different signal intensities of AVM when compared with other pulse sequences, thus providing clearer structural delineation. Routine use of the T1GRE pulse sequence can help pre-therapeutic planning or follow-up of AVM.

Angioarchitecture and clinical presentation of brain arteriovenous malformations

The purpose of this study was to correlate the angioarchitecture of brain arteriovenous malformations (AVM) with their clinical presentation. A total of 170 patients with AVM 78 males and 92 females, were studied. Univariate and multivariate analyses were conducted in order to test the associations between morphological features and clinical presentation. The most frequent clinical presentations at diagnosis were hemorrhage in 89 (52%) patients, headache in 79 (46%), focal neurological deficit in 54 (32%), and seizure in 52 (31%). According to the Spetzler-Martin classification, grade I was found in 15 patients, II in 49, III in 55, IV in 41, and grade V in 10 patients. AVM with small nidus size, single feeding artery and single draining vein were associated with hemorrhage. Hemorrhage was positively associated with Spetzler-Martin grade I and negatively with grade V. The association between seizure and large nidus size was positive, however negative with small nidus size.

Ruptured brain arteriovenous malformations in children: correlation of clinical outcome with admission parameters

AIMS

To gain a better understanding of how clinical outcome in children with ruptured brain arteriovenous malformations (bAVMs) correlates with clinical and imaging parameters on admission.

METHODS

The authors retrospectively reviewed patients with bAVMs, aged 18 or below, managed at their hospital between January 1992 and December 2008. Clinical outcome was assessed using the modified Rankin Scale (mRS). Patients with ruptured bAVMs were analyzed; their clinical parameters and computerized tomography findings on admission were recorded. Clinical outcome was then evaluated against admission scores using the Glasgow Coma Scale (GCS), the World Federation of Neurosurgical Societies Grading System of Subarachnoid Hemorrhage (WFNS-SAH), the Spetzler-Martin grade, the intracerebral hemorrhage score and 2 other independent parameters, namely pupillary response and significant focal neurological injuries. Spearman's correlation coefficient, linear regression analysis and multivariate logistic regression analysis were used for data analysis.

RESULTS

40 pediatric patients with bAVMs were found and 32 of them presented with hemorrhage (80%). In the 32 children with ruptured bAVMS, follow-up ranged between 7 and 204 months (median 100.5 months). The complete excision/obliteration rate as confirmed by digital subtraction angiography was 73.3%. The mRS scores at the last follow-up were: grades 0-II in 87.5%; grades IV-V in 6.25%, and grade VI in 6.25%. The Spetzler-Martin grade, the intracerebral hemorrhage score, the WFNS-SAH grade, the GCS scores, and a combined scoring scale consisting of the GCS, pupillary response and significant focal neurological injuries correlated significantly with clinical outcome 6 months after hemorrhage. However, on the scatter diagrams, it appeared that only the combined scoring scale might be valid for clinical practice. Multivariate logistic regression analysis showed that the combined scoring scale was a statistically significant independent predictor of clinical outcome 6 months after hemorrhage.

CONCLUSION

In this series of pediatric patients with ruptured bAVMs, although various grading scales correlated significantly with clinical outcome 6 months after hemorrhage, only the combined scoring scale might have the potential to be applied to predict clinical outcome in these children.

Gamma knife radiosurgery for arteriovenous malformations of basal ganglia, thalamus and brainstem--a retrospective study comparing the results with that for AVMs at other intracranial locations

OBJECTIVE

The objective of this retrospective study was to study the outcome in patients with basal ganglia, thalamus and brainstem (central/deep) arteriovenous malformations (AVMs) treated with gamma knife radiosurgery (GKS) and to compare the results with that for AVMs at other intracranial locations.

METHODS AND RESULTS

The results of 53 patients with central AVMs and 255 patients with AVMs at other locations treated with GKS at our center between April 1997 and March 2005 with minimum follow-up of 1 year were analyzed. CENTRAL AVMS: Forty of these 53 AVMs were Spetzler-Martin grade III, 11 were grade IV, and 2 were grade V. The mean AVM volume was 4.3 cm(3) (range 0.1-36.6 cm(3)). The mean marginal dose given was 23.3 Gy (range 16-25 Gy). The mean follow-up was 28 months (range 12-96 months). Check angiograms were advised at 2 years after GKS and yearly thereafter in the presence of residual AVM till 4 years. Presence of a residual AVM on an angiogram at 4 years after radiosurgery was considered as radiosurgical failure. Complete obliteration of the AVM was documented in 14 (74%) of the 19 patients with complete angiographic follow-up. Significantly lower obliteration rates (37% vs. 100%) were seen in larger AVMs (>3 cm(3)) and AVMs of higher (IV and V) Spetzler-Martin grades (28% vs. 100%). The 3- and 4-year actuarial rates of nidus obliteration were 68% and 74%, respectively. Eight patients (15%) developed radiation edema with a statistically significantly higher incidence in patients with AVM volume >3 cm(3) and in patients with Spetzler-Martin grade IV and V AVMs. Five patients (9.4%) had hemorrhage in the period of latency. COMPARISON OF RESULTS WITH AVMS AT OTHER LOCATIONS: Patients with central AVMs presented at a younger age (mean age 22.7 years vs. 29 years), with a very high proportion (81% vs. 63%) presenting with hemorrhage. Significantly higher incidence of radiation edema (15% vs. 5%) and lower obliteration rates (74% vs. 93%) were seen in patients with central AVMs.

CONCLUSIONS

GKS is an effective modality of treatment for central AVMs, though relatively lower obliteration rates and higher complication rates are seen compared to AVMs at other locations.

Clinical Features and Classification of Brain AVMs and Cranial DAVFs

The clinical findings of intracranial vascular malformations are strictly related to their morphologic, angioarchitectural and hemodynamic characteristics. An overall study of these features is the first step to understand the different classifications for arteriovenous malformations, dural arteriovenous fistulas and carotid-cavernous fistulas. This evaluation will also suggest the correct timing of endovascular treatment and which part of the lesion should be the target of the therapy. Conventional cerebral angiography is mandatory when a correct classification of intracranial arteriovenous malformative shunts must be achieved. The angioarchitectural classification of brain arteriovenous malformations considers all angiographic features of each component of the malformation, both morphologically and hemodynamically, and relates them to the clinical course of the disease. The correlation between clinical findings, angiographic features and classifications is even stronger for cranial dural arteriovenous fistulas, in which cortical venous drainage is typical of “aggressive” fistulas and is usually absent in the “benign” type. Similarly, carotid-cavernous fistulas can be differentiated at angiography into high or low flow lesions according to the flow rate of the shunt, and into direct or indirect fistulas, according to the origin of arterial feeders. This paper focuses on the existing relation between the hemodynamics of brain arteriovenous malformations, cranial dural arteriovenous fistulas, carotid-cavernous fistulas, and their most frequent clinical findings, through an analysis of the most widely used different classification systems.

Challenging traditional beliefs: microsurgery for arteriovenous malformations of the basal ganglia and thalamus

OBJECTIVE

Arteriovenous malformations of the basal ganglia and thalamus are often managed with radiosurgery or observation, without consideration of microsurgery. Given the devastating effects of hemorrhage from these lesions, the accumulating evidence that they bleed more frequently than their lobar counterparts should prompt more creative thinking regarding their management.

METHODS

A review of the endovascular, microsurgical, and radiosurgical literature for arteriovenous malformations of the basal ganglia and thalamus was performed, with close attention to surgical approaches, obliteration rates, and procedure-related complications.

RESULTS

A complete resection rate of 91% and a mortality rate of 2.4% were found across surgical series of these lesions. These contrast with a 69% rate of complete obliteration and a 5.3% mortality rate (from latency-period hemorrhage) found when compiling results across the radiosurgical literature.

CONCLUSION

Given an appropriate surgical corridor of access, often afforded by incident hemorrhage, arteriovenous malformations of the basal ganglia and thalamus should be considered for microsurgical extirpation with preoperative embolization. In experienced hands, this approach presents an expeditious and definitive opportunity to eliminate the risk of subsequent hemorrhage and resultant morbidity and mortality.

Spontaneous isolated convexity subarachnoid hemorrhage: presentation, radiological findings, differential diagnosis, and clinical course

Object

The clinical characteristics and overall outcome in patients with spontaneous isolated convexity subarachnoid hemorrhage (SAH) are not well described in the literature. The purpose of this study was to examine the mode of presentation, common origins, radiographic findings, and clinical course in a large case series of such patients.

Methods

A retrospective single-center chart review of all patients in whom nontraumatic primary convexity SAH was diagnosed between 2002 and 2007 was performed. Twenty patients were identified and analyzed for presenting symptoms, radiological and laboratory findings, hospital course, and outcome.

Results

There were 15 women and 5 men in our series, and the mean age was 52 years (range 18–86 years). The most common presenting symptom was headache, with 15 patients experiencing it as a chief complaint. Other frequent manifestations included altered mental status (8 patients), focal neurological deficits (7), and seizure (4 patients). An underlying cause of the hemorrhage was identified in 13 cases, whereas the remainder went unresolved. Of the known causes, 5 were due to posterior reversible encephalopathy syndrome, 3 were caused by thrombocytopenia or anticoagulation, and the remainder were isolated cases of lupus vasculitis, drug-induced vasculopathy, postpartum cerebral angiopathy, hypertensive microangiopathy, and Call–Fleming syndrome. All patients with unknown disease origins had favorable outcomes, whereas 8 of 13 patients with an identifiable underlying disorder experienced favorable outcomes.

Conclusions

Spontaneous isolated convexity SAH is rarely caused by aneurysm rupture, has a distinct mode of presentation, and generally carries a more favorable prognosis than that of aneurysmal SAH.

Endothelial molecular changes in a rodent model of arteriovenous malformation

Object

The cellular and molecular processes underlying arteriovenous malformation (AVM) development and response to radiosurgery are largely unknown. An animal model mimicking the molecular properties of AVMs is required to examine these processses. This study was performed to determine whether the endothelial molecular changes in an animal model of arteriovenous fistula (AVF) are similar to those in human AVMs.

Methods

Arteriovenous fistulas were created in 18 Sprague–Dawley rats by end-to-side anastomosis of the left jugular vein to the common carotid artery creating a model “nidus” of arterialized branching veins that coalesce into a “draining vein” (sigmoid sinus). Six control animals underwent sham operations.

Results

After 1 or 3 days, or 1, 3, 6, or 12 weeks, fresh-frozen sections of the fistula, nidus vessels, and contralateral vessels were studied immunohistochemically for thrombomodulin, von Willebrand factor, E-selectin, P-selectin, and vascular endothelial growth factor.

Conclusions

The AVF model has a “nidus” with endothelial molecular changes similar to those observed in human AVMs, supporting its use as a model for studying the effects of radiosurgery on AVMs.

A randomized trial of unruptured brain arteriovenous malformations (ARUBA)

Despite almost a century of efforts in the treatment of brain arteriovenous malformations (BAVMs) no clinical trial has yet been performed to demonstrate the benefits of intervention versus conservative (medical) management for those not yet bled. Only insufficient information on the natural history of unbled BAVMs exists to certify that intervention is needed and that such intervention produces a better long-term functional outcome.

Assessment of craniospinal arteriovenous malformations at 3T with highly temporally and highly spatially resolved contrast-enhanced MR angiography

BACKGROUND AND PURPOSE

Patients with arteriovenous malformation (AVM) are known to have an elevated risk of complications with conventional catheter angiography (CCA) but nonetheless require monitoring of hemodynamics. Thus, we aimed to evaluate both anatomy and hemodynamics in patients with AVM noninvasively by using contrast-enhanced MR angiography (CE-MRA) at 3T and to compare the results with CCA.

MATERIALS AND METHODS

Institutional review board approval and informed consent were obtained for this Health Insurance Portability and Accountability Act-compliant study. Twenty control subjects without vascular malformation (6 men, 18-70 years of age) and 10 patients with AVMs (6 men, 20-74 years of age) underwent supra-aortic time-resolved and high-spatial-resolution CE-MRA at 3T. Large-field-of-view coronal acquisitions extending from the root of the aorta to the cranial vertex were obtained for both MRA techniques. Image quality was assessed by 2 specialized radiologists by using a 4-point scale. AVM characteristics and nidus size were evaluated by using both CE-MRA and CCA in all patients.

RESULTS

In patients, 96.6% (319/330) of arterial segments on high-spatial-resolution MRA and 87.7% (272/310) of arterial segments on time-resolved MRA were graded excellent/good. MRA showed 100% specificity for detecting feeding arteries and venous drainage (n = 8) and complete obliteration of the AVM in 2 cases (concordance with CCA). Nidus diameters measured by both MRA and CCA resulted in a very strong correlation (r = 0.99) with a mild overestimation by MRA (0.10 cm by using the Bland-Altman plot).

CONCLUSION

By combining highly temporally resolved and highly spatially resolved MRA at 3T as complementary studies, one can assess vascular anatomy and hemodynamics noninvasively in patients with AVM.

[Treatment options for arteriovenous malformations]

Cerebral arteriovenous malformations are errors in the development of vasculature with shunts between cerebral arteries and veins, which manifest predominantly as intracerebral hemorrhage. To prevent hemorrhage, a complete obliteration of the arteriovenous malformation is necessary. For this purpose, techniques of microsurgery, radiotherapy, and embolization alone or in combination are available. This review article presents the treatment options and also summarizes available data from the literature on which therapy should be chosen in which situation and when watchful waiting should be preferred.

Microsurgery or Radiosurgery for Cerebral Arteriovenous Malformations? A Study of Two Paired Series

OBJECTIVE

To detect parameters that may augment the therapeutic strategy in patients with a cerebral arteriovenous malformation (AVM) that is considered equally suitable for treatment by neurosurgery or radiosurgery, we compared the efficacy and risks of these two methods in a paired series with similar patient and AVM characteristics.

PATIENTS AND METHODS

Two series of patients with AVM were studied, including a series of 39 patients treated using microsurgery (MS) and another series of 39 patients treated via radiosurgery (RS). These series were paired for age and sex, initial symptoms, size, location and Spetzler-Martin grade, and presence of embolization preceding treatment. We compared the posttreatment outcome in the two groups with respect to obliteration rate, neurological status, mortality rate, and recurrent bleeding. Statistical analysis was performed using paired Student's t test.

RESULTS

The Glasgow Outcome Scale values and Modified Rankin Scores measured at discharge and 12 to 24 months were significantly better in the RS series than in the MS series. The obliteration rate tended to be higher in the MS series (91% versus 81%; P = 0.10, not significant), whereas the rate of neurological deficit was higher in the MS series than in the RS series(P < 0.001). The mortality rate was not significantly different in the two series, but the rate of recurrent bleeding was higher in the RS group (10% versus 0%; P = 0.04).

CONCLUSIONS

Although the rate of cure was similar for patients treated with MS and RS, neurological morbidity was higher after MS and recurrent bleeding was more frequent after RS.

ARTERIOVENOUS MALFORMATIONS AFTER LEKSELL GAMMA KNIFE RADIOSURGERY

OBJECTIVE

Although relevant information exists regarding the chance of obliterating arteriovenous malformations (AVMs) using radiosurgery, the overall chance of cure after gamma knife radiosurgery is usually only extrapolated from a portion of all monitored patients. This chance and the risks involved in radiosurgery, including repeat treatment when necessary in a defined population of treated patients, were analyzed in our study.

METHODS

Between October 1992 and June 2000, gamma knife radiosurgery was performed on 330 patients with AVMs. The volume of the AVM nidus ranged from 0.15 to 28.6 cm3 (median, 3.9 cm3). When complete obliteration was not achieved within 3 years, repeat radiosurgery was performed on 76 patients. The volume of the nidus for the second treatment ranged from 0.09 to 16.8 cm3 (median 2.9 cm3). The result was reviewed in 300 (91%) patients after the first round of treatment and in 68 (89.5%) after the second round of treatment.

RESULTS

AVM obliteration was achieved in 222 (74%) patients after the first round of radiosurgery and in 47 (69%) after the second. The overall chance of cure was 92% (269 patients). Final angiography verified complete obliteration by 12 to 96 months (median, 25 mo) after initial radiosurgery. Smaller volume AVMs and the application of a higher radiation dose resulted in a higher chance of obliteration. The risk of rebleeding after radiosurgery was 2.1% annually until full obliteration, and the overall mortality from rebleeding was 1%. The risk of permanent morbidity after the first and second radiosurgery treatments were 2.7 and 2.9%, respectively. The cumulative risk of morbidity in both groups of patients was 3.4%.

CONCLUSION

Although one-quarter of the patients required that the treatment be repeated, gamma knife radiosurgery can offer a high cure rate for patients treated for AVMs with a low risk of morbidity and mortality from rebleeding during the latent period.

Treatment of arteriovenous malformations of the brain

The treatment of ruptured and unruptured brain arteriovenous malformations (AVMs) is driven by the need to prevent incident or recurrent intracranial hemorrhages. Improving feasibility of the rapidly developing endovascular, neurosurgical, and radiotherapeutic procedures leads to invasive treatment of an increasing number of neurologically intact patients with accidentally diagnosed AVMs. Recent data confirm that the natural history risk of unruptured AVMs is significantly lower than the risk of those presenting with rupture, and the treatment risk of invasive management of unruptured AVMs seems higher than their natural history risk. The treatment decision algorithm for these patients remains unsettled, as no randomized clinical trial data exist on the benefit of invasive AVM treatment for patients with bled or with unbled AVMs. The recently launched study A Randomized Trial of Unruptured Brain AVMs (ARUBA) will be the first trial randomizing patients with nonhemorrhaged AVMs to invasive versus conservative management.

Outcomes studies in cerebrovascular neurosurgery

✓Successfully measuring cerebrovascular neurosurgery outcomes requires an appreciation of the current state-of-the-art epidemiological instruments, their specific relevance to surgical treatments and the underlying pathological entity, and ultimately the right set of questions for the next generation of studies. In this paper the authors address these questions with specific attention to measurement targets, individual modeling scales, and types of studies, all within a conceptual framework for specific disease models in their current state of outcomes modeling in cerebrovascular neurosurgery.

Neurologie des malformations artérioveineuses cérébrales

INTRODUCTION

Brain arteriovenous malformations (AVMs) constitute a neurovascular disorder that comes to clinical attention mainly in young adults in their mid thirties. Associated symptoms often require neurological treatment for symptomatic seizures (focal or generalized), headaches (episodic or chronic), progressive neurological deficits, or spontaneous AVM rupture leading to intracerebral, intraventricular, and/or subarachnoid hemorrhage.

STATE OF ART

Little data exist in the medical literature regarding the natural history risk of the disease and no controlled studies are available on the risk of invasive AVM treatment (endovascular, neurosurgery, radiotherapy).

PERSPECTIVES

This review focuses on all aspects of neurological brain AVM management and discusses possible predictors of the natural history risk as well as the benefit and risk of invasive treatment.

CONCLUSIONS

AVM patient management is ideally based on a trans-disciplinary approach via a neurovascular team of neurologists, neuroradiologists, neurosurgeons, and radiotherapists. A newly diagnosed AVM does not necessarily represent an a priori indication for interventional treatment. The decision in favor or against therapy mainly depends on clinical criteria (ruptured versus unruptured AVM, neurological exam, patient age and co-morbidity, etc.) and the angioarchitecture of the malformation. The ARUBA study is going to be the first randomized clinical trial comparing the risk of invasive treatment versus non-invasive management.

Klebsiella meningitis mimicking clinical deterioration from hemorrhage of a complex posterior fossa arteriovenous malformation

We report a case of a 33-year-old male with a history of complex posterior fossa arteriovenous malformation (AVM) with partial resection done in China; at follow-up in our unit, he presented with a 1-day history of acute deterioration of consciousness level after minor head injury. The clinical and radiologic features were compatible with spontaneous hemorrhage from the AVM, and the patient died 1 day after admission. However, postmortem examination revealed the direct cause of death was due to Klebsiella meningitis. The clinical catch is highlighted, and the importance of early and prompt detection of this condition is emphasized.

Invasive treatment of unruptured brain arteriovenous malformations is experimental therapy

PURPOSE OF REVIEW

Brain arteriovenous malformations (AVMs) are currently being treated in a variety of ways, including medical management, endovascular procedures, neurosurgery and radiotherapy. The widespread diffusion of these various treatment approaches is partially driven by the existence of variations in the perception about the risks of rupture, and how devastating such events would be.

RECENT FINDINGS

Data from the most recent studies suggest the majority of AVM patients are diagnosed without signs of hemorrhage, further, that the natural history risk for the unruptured cohort is far more benign than for those presenting with rupture. In cases where hemorrhage occurs, the clinical syndrome is significantly less disabling than in patients with non-AVM related hemorrhage. For unruptured AVMs, current morbidity data suggest a higher risk for invasive management than for the natural history of untreated patients.

SUMMARY

No randomized clinical trial data exist on the benefit of invasive AVM treatment, and the most contentious issue at present is whether intervention should be considered for AVMs that have not bled. In a scientific sense, invasive treatment for unruptured brain AVMs may be considered experimental therapy awaiting the results from 'A Randomized Trial of Unruptured Brain AVMs' (ARUBA), which is currently underway.

Fatal hemorrhagic complication following endovascular treatment of a cerebral arteriovenous malformation

Evaluation of the natural history of brain Arteriovenous Malformations (AVMs) including its morbidity and mortality is a crucial point in the management of patients having a cerebral AVM. The risks associated with the AVM natural history, especially regarding the occurrence of an hemorrhage, have to be compared to the risks due to the therapeutic approach. In the literature, the risk of annual bleeding of an AVM is estimated from 2 to 4%. Morbidity from AVM rupture is estimated from 13% to 50% with a risk of mortality reported from 3 to 30%. Endovascular treatment is an efficient tool in the therapy of these lesions. However, AVM embolization remains a difficult procedure. Complications of the endovascular treatment must be evaluated in relation to the potential risk associated to the AVM natural history. After AVM endovascular treatment, morbidity with permanent neurological deficit is reported in 0.4% to 12.5% of patients and mortality in 0.4% to 7.5%. In more recent reports, after brain AVM embolization, a permanent neurological deficit is estimated to occur in 9% of patients and death in 2%. Hemorrhage appears the most frequent and serious complication in the endovascular treatment of a brain AVM. We report a case of fatal hemorrhagic complication following endovascular treatment of a cerebral AVM in a 20 year old patient. This case contributes to remind that embolization, even in specialized centers with experience in the management of this pathology, can be followed by a poor and even fatal outcome. In most cases, the treatment is performed in order to protect the patient of a potential risk. Consequently, the complication of the embolization must always be carefully considered and discussed between the medical team, the patient and its family for planning the AVM endovascular treatment.

Complication analysis of 469 brain arteriovenous malformations treated with N-butyl cyanoacrylate

SUMMARY

We independently assessed the frequency, severity and determinants of neurological deficits after endovascular embolization with NBCA of brain arteriovenous malformations (BAVMs) to have a better basis for making treatment decisions. All the charts of 469 BAVMs patients who underwent embolization with NBCA were reviewed. We analyzed the complications and their relation to angiographic features. The 469 patients were treated with 1108 endovascular procedures. Each met one to eight times, average 2.3 times. Eleven patients showed treatment-related complications, including four haemorrhagic and seven ischemic complications. Of these 11 cases, two died, two had persistent disabling deficits, and another seven suffered transient neurological deficits. Our finding suggests a low rate of disabling treatment complications for embolization of brain AVMs with NBCA in this center. The management of AVM patients who have high risk of embolization therapy should be treated by special strategy.

Management of brain arteriovenous malformations

PURPOSE OF REVIEW

This review highlights recent data regarding factors associated with brain arteriovenous malformation hemorrhage and different treatment options.

RECENT FINDINGS

More risk factors were identified in association with intracranial hemorrhage, including age at initial diagnosis of arteriovenous malformation, co-existing extranidal aneurysms and genetic factors. Patients with unruptured arteriovenous malformations were found to be more susceptible to worsening in neurological function after microsurgery compared with those presenting with hemorrhagic arteriovenous malformation. Radiosurgery has achieved satisfactory obliteration of deep arteriovenous malformations, but with increased actuarial hemorrhage rates from the first to the fifth year. Although the Intraoperative Hypothermia for Aneurysm Surgery Trial failed to show a significant neurological improvement, the superior efficiency of endovascular cooling has offered optimism in cerebral protection during neurovascular surgeries by shortening the time to achieve hypothermia and rewarming. A multi-center trial (ARUBA) has been proposed to test the hypothesis that, for unruptured brain arteriovenous malformations, there is no difference between interventional and conservative management. Recent studies have also shown the promise of using tetracyclines to decrease the rate of spontaneous arteriovenous malformation rupture.

SUMMARY

The recent identification of clinical and genetic factors associated with brain arteriovenous malformation hemorrhage, as well as studies on treatment outcomes, will help risk stratification in management choices. Future studies are needed to identify arteriovenous malformation patients at the greatest risk of spontaneous hemorrhage and to develop specific medical therapies.

Characterization of the Integrin αvβ3 in Arteriovenous Malformations and Cavernous Malformations

BACKGROUND

Alpha V beta 3 (alphavbeta3) is an integrin specifically expressed on the endothelial cells of central nervous system (CNS) neoplasms. However, no data exist on the expression of alphavbeta3 in vascular malformations of the CNS. In this study, we investigate the expression of alphavbeta3 in arteriovenous malformations (AVMs) and cavernous malformations (CMs).

METHOD

Frozen samples of AVMs from 12 patients and CMs from 5 patients were obtained intraoperatively. Once the final pathology had been confirmed, immunohistochemistry was performed using an antibody to the integrin alphavbeta3. The alphavbeta3 expression pattern was graded according to the percentage of positively staining vessels.

RESULTS

Ten of 12 AVMs demonstrated alphavbeta3 immunopositivity. Six of these 10 AVMs had moderate or strong staining. Most notably, 5 of the 6 moderate or strongly staining AVMs came from patients 22 years of age or younger. Four of these 6 AVMs had previously been embolized. None of the cavernous malformations demonstrated alphavbeta3 immunopositivity.

DISCUSSION

alphavbeta3 may contribute to the formation of AVMs in younger patients. alphavbeta3 may also provide a potential therapeutic target. The lack of alphavbeta3 expression in cavernous malformations, despite their high vascular densities, suggests that the pathophysiology of their formation differs from that of AVMs.

Brain arteriovenous malformations in adults

Arteriovenous malformations of the brain (AMB) can cause stroke when they rupture. Epidemiological and imaging research has found that about 50% of patients with AMB present with haemorrhage, and the other 50% either present with non-focal symptoms, such as headache, seizure, or focal neurological deficit, or have no symptoms and the lesion is found during unrelated investigations. Treatment for arteriovenous malformations aims to prevent and resolve haemorrhage and is a growing interdisciplinary challenge. Although treatment uses enormous resources, there have been few studies on the risk-benefit ratios for treatment of unruptured AMB and the best approaches.

Does treatment with N-butyl cyanoacrylate embolization protect against hemorrhage in cerebral arteriovenous malformations?

OBJECTIVE

To assess the role of this procedure to prevent hemorrhage in cerebral arteriovenous malformations (cAVM).

METHOD

Between 1992 and 2000, we studied 104 patients submitted to embolization as the main treatment. Patients were followed until hemorrhage or death.

RESULTS

Follow-up ranged from 1.6 months to 8 years. The most frequent presentations were hemorrhage (50%) and seizures (38%). In addition, 40% were small (<30 mm); 56% were medium (30-60 mm). Obliteration was < or =1/3 in 11% of the cases; from 1/3 to < or = 2/3 in 49%; >2/3 in 36%; complete in 5%. The risk of death was 1%/year, and of bleeding, 5.4%/year. Presentation with hemorrhage and low obliteration rate were the main factors associated with hemorrhage.

CONCLUSION

cAVM embolization provides limited protection against hemorrhage with obliteration rates below 2/3. Presentation with hemorrhage is the main factor for predicting hemorrhage.

[Cerebral arteriovenous malformations: evaluation of the hemorrhagic risk and its morbidity]

Evaluation of the hemorrhagic risk associated with intracranial arteriovenous malformation is a keypoint question for physicians involved in the management of these patients. Indeed, this hemorrhagic risk including its morbid-mortality consequences has to be balanced with the therapeutic risk. All the published studies have estimated the annual bleeding risk between 2 to 4%; a first hemorrhagic event is associated with an increased risk of a new bleeding. Mortality associated with AVM bleeding is estimated between 10 to 15%, with a 50% risk of morbidity. Factors associated with an increased risk of bleeding include existence of aneurysms (intranidal or flow related pedicular, proximal or distal) and some venous drainage patterns such as deep venous drainage or venous stenosis.

Natural history, evaluation, and management of intracranial vascular malformations

Intracranial vascular malformations are seen increasingly in clinical practice, primarily because of advances in cross-sectional brain and spinal cord imaging. Commonly encountered lesion types include arteriovenous malformations, cavernous malformations, venous malformations, dural arteriovenous fistulas, and capillary telangiectasias. Patients can experience various symptoms and signs at presentation. The natural history of vascular malformations depends on lesion type, location, size, and overall hemodynamics. The natural history for each lesion subtype is reviewed, with special consideration of the risk of hemorrhage or other adverse outcomes after the lesion is detected and any known predictors of hemorrhage or other outcomes. In practice, these data are compared with the risk of available treatment options as the optimal management is clarified. A multidisciplinary approach including neurosurgery, radiosurgery, interventional neuroradiology, and vascular neurology is most useful in determining the best management strategy.

Radiosurgery for Basal Ganglia, Internal Capsule, and Thalamus Arteriovenous Malformation: Clinical Outcome

OBJECTIVE:

Radiosurgery is accepted as the first option for treating deep arteriovenous malformations (AVMs), although the clinical outcome in this subgroup of brain AVMs is not well studied. The objective of this study is to review our experience with radiosurgical treatment for these AVMs.

METHODS:

Between October 1989 and December 2000, 45 patients with deep AVMs (including basal ganglia, internal capsule, and thalamus) underwent stereotactic radiosurgery. Three patients were lost to follow-up and therefore were excluded from this study. Patient characteristics and outcomes were collected and analyzed. The obliteration prediction index and the radiosurgery-based AVM score were calculated and tested.

RESULTS:

Forty-two patients were followed up for a median of 39 months (range, 25–90 mo; mean, 45.8 mo). The median maximum AVM diameter during the radiosurgery was 1.8 cm (range, 0.9–4.0 cm; mean, 2.07 cm), and the median AVM volume was 2.8 cm3 (range, 0.2–18.3 cm3; mean, 4.74 cm3). The mean marginal dose was 16.2 Gy (median, 15 Gy), and the median maximum dose was 22.4 Gy (range, 16.6–30 Gy). The AVM cure rate after the first radiosurgical treatment, using angiography- and magnetic resonance imaging-confirmed obliteration, was 61.9%. The predicted obliteration using the obliteration prediction index was 60%. Eight patients developed radiation-induced complications (19%). The deficit was transient in three patients (7.1%) and permanent in five patients (11.9%). The risk of postradiosurgical hemorrhage in this cohort was 9.5% for the first year, 4.7% for the second year, and 0% thereafter. Excellent outcome (obliteration plus no new deficit) was achieved in 70% of the patients in the group with radiosurgery-based AVM score less than 1.5 compared with 40.9% in the group with radiosurgery-based AVM score greater than 1.5% (P = 0.059).

CONCLUSION:

Radiosurgery for deep AVMs has a satisfactory obliteration rate and acceptable morbidity, considering the risk of hemorrhage without treatment and the risk of morbidity associated with other treatment modalities.

Hemorrhage from moyamoya-like vessels associated with a cerebral arteriovenous malformation

✓ The authors describe a case of subarachnoid hemorrhage from moyamoya-like vessels associated with an arteriovenous malformation (AVM) in a 44-year-old Hispanic man who presented with severe headache. The AVM was located in the left parietal lobe and the ipsilateral middle cerebral artery was occluded. Although the patient was initially neurologically intact, he began to experience neurological deficits from mild vasospasm, illustrating the sensitivity of the underperfused portion of brain surrounding an AVM. His neurological deficits improved with aggressive hydration and elevated blood pressure. After a 3-week period, the AVM was resected without complication and all of the patient's neurological deficits resolved. The authors review radiographic findings of this unique case.

Ventricular arteriovenous malformation bleeding: a rare cause of headache in children. Case report

Headache as a chief complaint is rare in the paediatric emergency room. Actually, very seldom cases secondary to life threatening conditions as non-traumatic subarachnoid haemorrhage have been reported. A child with severe headache and nuchal rigidity and no other abnormalities on the physical examination is reported. Magnetic resonance angiography and cerebral angiography disclosed a ventricular arteriovenous malformation in the choroid plexus, supplied by the anterior choroidal artery, classified according to Spetzler grading system as grade 3 (deep venous drainage: 1; eloquence area: 0 and size: 2). The differences in the clinical presentations of the central nervous system arteriovenous malformation between children and adults are discussed.