Radiosurgery for cerebral arteriovenous malformations in hereditary hemorrhagic telangiectasia

Stereotactic radiosurgery for brain arteriovenous malformations in patients with hereditary hemorrhagic telangiectasia

OBJECTIVE

Brain arteriovenous malformations (AVMs) in patients with hereditary hemorrhagic telangiectasia (HHT) present different characteristics from sporadic AVMs, and they have lower initial bleeding rates. Conservative management is usually preferred for the treatment of these lesions. In this case study, we present the largest series of HHT patients treated with stereotactic radiosurgery to date.

METHODS

We identified eight patients with HHT and 14 AVMs. We retrospectively collected clinical, radiographic, and treatment characteristics of the patients and each AVM.

RESULTS

Most patients in our sample presented with small AVMs. The median volume of these AVMs was 0.22 cm3 (IQR 0.08-0.59). Three out of eight patients presented with initial intracerebral hemorrhage (ICH). The majority of lesions had low (12/14) Spetzler-Martin grades (I-II). Median maximum and margin doses used for treatment were 36.2 (IQR 35.25-44.4) and 20 (IQR 18-22.5) Gy, respectively. The overall obliteration rate after SRS was 11/14, and the median time to obliteration across all 11 obliterated AVMs was 35.83 months (IQR, 17-39.99). Neurological status was favorable with all patients having a mRS of 0 or 1 at the last follow-up. Symptomatic radiation-induced changes (RIC) after SRS were low (7.1%), and there were no permanent RIC.

CONCLUSIONS

Patients with HHT who present with multiple brain AVMs are generally well served by SRS. Obliteration can be achieved in the majority of HHT patients and with a low complication rate. In the current study, initial hemorrhage rates prior to SRS were noticeable which supports the decision to treat these AVMs. Future studies are needed to better address the role of SRS for HHT patients harboring ruptured and unruptured AVMs.

Comparing Characteristics and Treatment of Brain Vascular Malformations in Children and Adults with HHT

Hereditary hemorrhagic telangiectasia (HHT) is a rare autosomal dominant disease characterized by the development of vascular malformations (VMs) in organs such as the brain and lungs, as well as telangiectases on mucosal surfaces. Prophylactic treatment of organ VMs may prevent potential complications, such as hemorrhage. However, brain VM treatment-surgical resection, embolization, and/or radiosurgery-is not recommended for all patients due to the associated risks. Given the scarcity of data regarding HHT-related brain VM presentation and treatment trends in pediatric patients, we aim to describe the clinical presentations and the patterns of treatment of HHT-related brain VMs in a pediatric cohort, and compare pediatric trends to those of adults. Demographic and clinical data were analyzed in 114 pediatric patients with HHT-related brain VMs and compared with a cohort of 253 adult patients enrolled in the multicenter Brain Vascular Malformation Consortium HHT Project. Our data demonstrated that a higher proportion of pediatric patients with HHT-related brain VMs were symptomatic at presentation (p = 0.004). Moreover, a higher proportion of pediatric patients presented with intracranial hemorrhage (p < 0.001) and seizure (p = 0.002) compared to adult patients. Surgical resection was the most common brain VM treatment modality in both children and adults. We conclude that pediatric patients may be more likely to present with symptoms and complications from brain VMs, supporting the case for screening for brain VMs in children with HHT.

Surgical Treatment vs Nonsurgical Treatment for Brain Arteriovenous Malformations in Patients with Hereditary Hemorrhagic Telangiectasia: A Retrospective Multicenter Consortium Study

BACKGROUND

Cerebral arteriovenous malformations (AVMs) are common in patients with hereditary hemorrhagic telangiectasia (HHT). However, due to the rarity of HHT and little published evidence of outcomes from management of brain AVMs in this disease, current international HHT guidelines recommend an individualized approach. Specifically, the outcomes for surgical vs nonsurgical management of these lesions have not been reported to date.

OBJECTIVE

To report long-term outcomes of surgical resection of brain AVMs in HHT patients compared to outcomes in nonsurgically treated patients.

METHODS

From the database of the Brain Vascular Malformation Consortium HHT project, 19 patients with 20 resected AVMs (group 1) and 22 patients with 33 AVMs who received nonsurgical treatment (group 2) were studied. The groups were retrospectively reviewed for changes in functional status (modified Rankin Scale score) during the follow-up period.

RESULTS

During the follow-up period, 9% of patients in group 1 suffered from worsening of functional status, whereas this figure was 16% for group 2 (P > .05). Functional outcomes were not statistically different between the 2 groups at the latest follow-up (P > .05).

CONCLUSION

HHT patients treated surgically for brain AVMs appear to have long-term functional outcomes comparable to nonsurgical (including observational) therapy with fewer unfavorable outcomes. It is therefore reasonable to consider surgical resection as a management option in the multidisciplinary team's individualized treatment strategy for HHT patients with brain AVMs.

Clinical presentation and treatment paradigms of brain arteriovenous malformations in patients with hereditary hemorrhagic telangiectasia

Hereditary hemorrhagic telangiectasia (HHT) is characterized by recurrent spontaneous epistaxis, mucocutaneous telangiectases, and multisystem arteriovenous malformations (AVMs). Brain AVMs typically present at birth and are identified in approximately 10-20% of patients with HHT. A retrospective review was undertaken of all HHT patients with known single or multiple brain AVMs treated at our institution. Thirty-nine patients with brain AVM(s) were diagnosed with HHT. Most patients presented with at least one Curaçao criterion. A total of 78 brain AVMs were identified in 39 patients. Two-thirds of patients had solitary brain AVMs, whereas 33% of patients harbored at least two lesions (range: 2-16). Brain AVMs of the supratentorial cerebral hemispheres comprised 83% of all lesions, whereas infratentorial lesions accounted for only 17%. Of the 55 brain AVMs assigned Spetzler-Martin grading, the majority of patients were Grade 1 (73%), and 23% and 4% were Grades 2 and 3, respectively. Patients were treated with surgery alone (51%), embolization alone (6%), embolization followed by surgery (9%), stereotactic radiosurgery (11%), stereotactic radiosurgery followed by surgery (3%), or observation (20%). Of patients who underwent genetic analysis, 62% possessed mutations in ENG (HHT type 1), whereas 38% had mutations in ACVRL1 (HHT type 2). This robust patient cohort of brain AVMs in 39 patients with HHT advances the collective understanding of this disease's varied presentation, diagnostic workup, genetic underpinnings, and available treatment options.

Lower Risk of Intracranial Arteriovenous Malformation Hemorrhage in Patients With Hereditary Hemorrhagic Telangiectasia

BACKGROUND

Patients diagnosed with hereditary hemorrhagic telangiectasia (HHT) are at risk of developing intracranial arteriovenous malformations (AVM). However, the clinical manifestations and natural history of HHT-related AVMs remain unclear due to the rarity of these lesions.

OBJECTIVE

To clarify the clinical characteristics and hemorrhagic risk in HHT-related AVMs.

METHODS

We performed a retrospective review of all patients diagnosed with both HHT and intracranial AVMs who were evaluated at our institution from 1990 to 2013. Patients with missing data or lost to follow-up were excluded. Baseline characteristics and subsequent hemorrhagic risk were evaluated.

RESULTS

In an AVM database of 531 patients with 542 AVMs, a total of 12 HHT patients (2.3%) with 23 AVMs were found. Mean age at diagnosis was 36.5 years, with 41.7% male. Compared to patients with sporadic AVMs, patients with HHT were less likely to present with ruptured AVM (P = .04), headaches (P = .02), and seizures (P = .02), and presented with better modified Rankin scores (P < .01). HHT-related AVMs were smaller in size (P < .01), of lower Spetzler-Martin grade (P = .01), and had less temporal lobe involvement (P = .02) compared to sporadic AVMs. Six HHT patients (50.0%) were found with multiple intracranial AVMs. One hemorrhage was found during an observation period of 149.6 patient-years and 297.5 lesion-years, translating to 1.3% per patient per year or 0.7% per AVM per year.

CONCLUSION

HHT-related AVMs are smaller in size with lower Spetzler-Martin grade and less temporal lobe involvement than sporadic AVMs. Patients with HHT frequently present with multiple intracranial AVMs. Conservative management is generally recommended due to lesion multiplicity and relatively low hemorrhagic risk.

Prevalence and characteristics of brain arteriovenous malformations in hereditary hemorrhagic telangiectasia: a systematic review and meta-analysis

OBJECTIVE Patients with hereditary hemorrhagic telangiectasia (HHT) are known to suffer from high rates of cerebral arteriovenous malformations (AVMs). The authors performed a systematic review and meta-analysis of the literature examining prevalence rates, characteristics, and clinical presentation of cerebral AVMs in the HHT population. METHODS To identify studies on AVM prevalence and characteristics in the HHT population, 4 databases (MEDLINE, EMBASE, Scopus and Web of Science) were searched by a reference librarian with over 30 years experience in systematic reviews and meta-analysis. The search period was January 1, 1990-March 2016. The following search terms were used: hereditary hemorrhagic telangiectasia, Osler-Weber-Rendu syndrome, AVM, brain AVM, arteriovenous malformation, arteriovenous fistula, prevalence, and epidemiology. The authors identified studies that examined the prevalence rates, characteristics, and clinical presentation of cerebral AVMs in patients with HHT. They assessed overall AVM prevalence rates as well as prevalence rates by age, sex, HHT type, and country/region. They also systematically reviewed the characteristics of AVMs, including rupture status, location, clinical presentation, angioarchitecture, and Spetzler-Martin grade. Data were analyzed using a random-effects meta-analysis model. RESULTS Thirty-nine studies were included in this meta-analysis. Thirty studies examined brain AVM prevalence rates in various HHT patient populations, and 18 studies examined AVM clinical and angiographic characteristics (9 studies examined both prevalence rates and AVM characteristics). The prevalence of brain AVMs in HHT patients was 10.4% (95% CI 7.9%-13.0%) with no significant difference between males (8.5%, 95% CI 4.9%-12.0%) and females (11.0%, 95% CI 5.9%-16.1%). Patients with HHT Type 1 (HHT1) had a significantly higher brain AVM prevalence (13.4%, 95% CI 9.5%-17.4%) compared with those with HHT Type 2 (HHT2) (2.4%, 95% CI 1.0%-3.8%) (p < 0.0001). In 55.2% (95% CI 38.3%-72.1%) of cases, the AVMs were symptomatic. Spetzler-Martin grade was 2 or less in 86.9% (95% CI 67.5%-95.2%) of patients. CONCLUSIONS The prevalence of brain AVMs in the HHT population is about 10%. HHT1 patients are significantly more likely to have brain AVMs than HHT2 patients. Most AVMs in the HHT population are symptomatic. The Spetzler-Martin grade for these lesions is 2 or less in nearly 90% of patients.

Neurological involvement in hereditary hemorrhagic telangiectasia

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant disorder characterized by epistaxis, telangiectases, and multi-organ vascular dysplasia. Head and neck localizations of HHT are recurrent, frequent associated with serious complications. The aim of this study was to describe the clinical and imaging patterns of neurological involvement in HHT and to discuss the role of interventional radiology in the management of HHT patients. Based on a multidisciplinary experience of twenty years at our center, we report here the different aspects of neurological involvement of HHT. Depending on the genetic type of the disease, vascular abnormalities may affect different organs. The knowledge of neurological involvement according to specific localization of HHT makes detection easier. As cerebral or spinal arteriovenous fistula may be present in patients with epistaxis or pulmonary arteriovenous malformations (PAVMs), radiologists should be able to detect high-risk lesions and prevent related complications. Finally, we review indications and techniques of embolization for hemorrhagic lesions and emphasize that endovascular therapies are very effective and safe in experienced hands. Head and neck imaging is commonly used for the diagnosis of HHT. Imaging plays also a key role for patient evaluation before treatment as pluridisciplinary management is needed.

[Osler's disease]

Osler's disease, also known as hereditary hemorrhagic telangiectasia (HHT) and Osler-Weber-Rendu syndrome, is an autosomal dominant disorder leading to abnormal blood vessel formation in the skin, mucous membranes and often in organs, such as the lungs, liver and brain (arteriovenous malformations AVM). Various types are known. Patients may present with epistaxis. Teleangiectasia can be identified by visual inspection during physical examination of the skin or oral cavity or by endoscopy. Diagnosis is made after clinical examination and genetic testing based on the Curacao criteria. Modern imaging modalities, such as computed tomography (CT) or magnetic resonance imaging (MRI) have become more important as they can depict the AVMs. Pulmonary AVMs can be depicted in CT imaging even without the use of a contrast agent while other locations including the central nervous system (CNS) usually require administration of contrast agents. Knowledge of possible clinical manifestations in various organs, possible complications and typical radiological presentation is mandatory to enable adequate therapy of these patients. Interventional procedures are becoming increasingly more important in the treatment of HHT patients.

Stereotactic LINAC radiosurgery for the treatment of brainstem cavernomas

BACKGROUND

The management of deep-seated cerebral cavernous malformations (CCMs) is still controversial. Although surgery remains the treatment of choice in patients with recurrent hemorrhage, patients with CCMs located in the brainstem are in many cases not eligible for resection due to high procedure-related morbidity and mortality. We evaluated the long-term outcome of LINAC radiosurgery (LINAC-RS) for the treatment of brainstem CCMs.

PATIENTS AND METHODS

Between December 1992 and March 2008, 14 patients (6 men, 8 women) harboring brainstem CCMs underwent LINAC-RS. Pretreatment neuroimaging showed no associated developmental venous angiomas (DVAs) in any of our patients. Prior to treatment, all patients suffered at least from one symptomatic hemorrhage (median 1.8, range 1–3). A median follow-up of 7.1 years (range 2.0–16.8 years) could be obtained in 12 patients. We applied a median tumor surface dose of 13.9 Gy (range 11–18 Gy; median tumor volume 1.6 ml, range 0.4–4.3 ml).

RESULTS

Following LINAC-RS, neurological outcome improved in 4 (33.3%) and remained unchanged in 8 patients (66.7%). Rebleeding with subsequent transient neurological status deterioration occurred in 4 patients (33.3%), leading to additional surgical resection in 2 patients (16.7%). The corresponding annual hemorrhage rate was 4.8% (4/82.8 patient–years). Adverse radiation effects (ARE, defined by perilesional hyperintensity on T2-weighted MR images) were revealed in 3 patients (25%), leading to transient neurological deficits in 2 patients (16.7%). There were no procedure-related complications leading to either permanent morbidity or mortality.

CONCLUSION

Our results support the role of LINAC-RS as an efficient and safe treatment to significantly reduce the annual hemorrhage rate in patients suffering from brainstem CCMs not eligible to microsurgery. Compared with radiosurgery for arteriovenous malformations (AVMs), the intervention-related morbidity is higher.

Radiosurgery for arteriovenous malformations

Stereotactic radiosurgery is the term coined by Lars Leksell to describe the application of a single, high dose of radiation to a stereotactically defined target volume. In the 1970s, reports began to appear documenting the successful obliteration of arteriovenous malformations (AVMs) with radiosurgery. When an AVM is treated with radiosurgery, a pathologic process appears to be induced that is similar to the response-to-injury model of atherosclerosis. Radiation injury to the vascular endothelium is believed to induce the proliferation of smooth-muscle cells and the elaboration of extracellular collagen, which leads to progressive stenosis and obliteration of the AVM nidus thereby eliminating the risk of hemorrhage. The advantages of radiosurgery - compared to microsurgical and endovascular treatments - are that it is noninvasive, has minimal risk of acute complications, and is performed as an outpatient procedure requiring no recovery time for the patient. The primary disadvantage of radiosurgery is that cure is not immediate. While thrombosis of the lesion is achieved in the majority of cases, it commonly does not occur until two or three years after treatment. During the interval between radiosurgical treatment and AVM thrombosis, the risk of hemorrhage remains. Another potential disadvantage of radiosurgery is possible long term adverse effects of radiation. Finally, radiosurgery has been shown to be less effective for lesions over 10 cc in volume. For these reasons, selection of the optimal treatment for an AVM is a complex decision requiring the input of experts in endovascular, open surgical, and radiosurgical treatment. In the pages below, we will review the world's literature on radiosurgery for AVMs. Topics reviewed will include the following: radiosurgical technique, radiosurgery results (gamma knife radiosurgery, particle beam radiosurgery, linear accelerator radiosurgery), hemorrhage after radiosurgery, radiation induced complications, repeat radiosurgery, and radiosurgery for other types of vascular malformation.

Stereotactic LINAC radiosurgery for incompletely resected or recurrent atypical and anaplastic meningiomas

BACKGROUND

The optimal management of subtotally resected or recurrent malignant meningiomas remains controversial. We evaluated the efficacy of linear accelerator (LINAC) radiosurgery for atypical and anaplastic meningiomas after incomplete resection or treatment of recurrences.

METHODS

Between August 1990 and December 2003, 16 patients with 28 meningiomas WHO II and III were treated by stereotactic LINAC radiosurgery at our institution. The median radiological follow-up was 60.3 months, respectively (range: 7.2-173.9 months). Fourteen tumors in nine patients were classified as WHO II and 14 tumors in seven patients as WHO III. The median surface dose was 14 Gy (range: 10-15 Gy) with a median tumor volume of 4.8 ml (range: 0.51-51.4 ml).

RESULTS

Clinical condition improved in four patients, remained unchanged in nine and deteriorated in one. Tumor shrinkage was seen in eight of 28 meningiomas and a stable disease in 12. Eight of 28 meningiomas showed local tumor progression. The overall tumor control rate (TCR) was 84%, 70%, 70% after 3, 5, 10 years. According to grading the corresponding TCR after 3, 5, 10 years was 91%, 81%, 81% for grade II and 77%, 60%, 60% for grade III meningiomas. Overall progression-free survival (PFS) was 74%, 67%, 58% after 3, 5, 10 years. According to grading the PFS after 3, 5, 10 years was 88%, 75%, 75% for grade II meningiomas and 57%, 57%, 43% for grade III meningiomas.

CONCLUSION

Our results show the efficacy and safety of LINAC radiosurgery for incompletely resected or recurrent malignant meningiomas with a relatively high local tumor control and low morbidity.

Imaging of hereditary hemorrhagic telangiectasia

This pictorial review is based on our experience of the follow-up of 120 patients at our multidisciplinary center for hereditary hemorrhagic telangiectasia (HHT). Rendu-Osler-Weber disease or HHT is a multiorgan autosomal dominant disorder with high penetrance, characterized by epistaxis, mucocutaneous telangiectasis, and visceral arteriovenous malformations (AVMs). The research on gene mutations is fundamental and family screening by clinical examination, chest X-ray, research of pulmonary shunting, and abdominal color Doppler sonography is absolutely necessary. The angioarchitecture of pulmonary AVMs can be studied by unenhanced multidetector computed tomography; however, all other explorations of liver, digestive bowels, or brain require administration of contrast media. Magnetic resonance angiography is helpful for central nervous system screening, in particular for the spinal cord, but also for pulmonary, hepatic, and pelvic AVMs. Knowledge of the multiorgan involvement of HHT, mechanism of complications, and radiologic findings is fundamental for the correct management of these patients.

Neurovascular radiosurgery

SUMMARY

This article focuses on the treatment of neurovascular diseases, in particular brain arteriovenous malformations (BAVMs), with radiosurgery. The target group for this review is physicians who manage patients with neurovascular diseases, but are not actively engaged in radiosurgery. Radiosurgery for BAVMs is an established treatment with clearly defined risks and benefits. The efficacy of radiosurgery for dural arteriovenous shunts (DAVSs) is probably similar but the treatment has not yet gained the same acceptance. Radiosurgical treatment of cavernomas (cavernous hemangiomas) remains controversial. Well founded predictive models for BAVM radiosurgery show: * The probability of obliteration depends on the dose of radiation given to the periphery of the BAVM. * The risk of adverse radiation effects depends on the total dose of radiation, i.e. the amount of energy imparted into the tissue. The risk is greater in centrally located lesions. The risk of damage to brainstem nucleii and cranial nerves must be added to the risk predicted from current outcome models. * The risk of hemorrhage during the time span before obliteration depends on the BAVM volume, the dose of radiation to the periphery of the lesion and the age of the patient. Central location is a probably also a risk factor.