Overview of Cerebrovascular Malformations

Transcription

1 Overview of Cerebrovascular Malformations Pursuit of Neurovascular Excellence 8 th annual Barbara Albani, MD Chief, Neurointerventional Surgery Christiana Care Health Systems Newark, DE

2 Financial Disclosures None

3 Objectives Present an overview of vascular malformations of the brain Review the pathophysiology and natural history of cerebrovascular malformations Explore current management strategies Describe treatment options for these lesions

4 Cerebrovascular Malformations Primarily congenital lesions of cerebral vessels 0.1-4% population Two classifications Histopathologic Functional (high/low flow)

5 Histopathology Arteriovenous malformations (AVMs) Arterial nidus (nest) Draining vein No intervening capillary bed Venous angiomas (DVA) Dilated WM veins Normal intervening brain Capillary telangiectasias Dilated capillaries Normal brain Cavernous malformations. Blood lakes No normal brain Pathological section cavernous malformation

6 Functional Non Shunting lesions (low flow) Occult angiographically Microsurgical /XRT or no treatment Shunting lesions (high flow) Seen angiographically Endovascular treatment considered Arteriovenous malformation

7 Low Flow NON-SHUNTING LESIONS

8 Non shunting lesions Types Developmental venous anomaly Capillary telangictasia Cavernous malformation Sinus Peri Cranii (will not review) Developmental venous anomaly

9 Developmental venous anomalies (aka venous angiomas, venous malformations) Incidence Most common CVM (60%) 2% Population Pathology Functional vein Persistent fetal drainage Relationship with cav mal Usually solitary Rare Multiple Blue rubber bleb nevus syn Incidental / do not touch Rare to bleed (0.15%/yr) Contrast MRI

10 Developmental venous anomalies CT- often negative MRI and CTA (choice) Radial pattern of vessels converging on an enlarged central trunk May occasionally be confused for an AVM Angiography Visible on angiography as a normal variant of venous drainage without arteriovenous shunting Caput medusa Imaging Angiogram Medusa

11 Developmental venous anomalies MRI: T1 with contrast

12 Developmental venous anomalies Angiography

13 Capillary telangiectasias (aka capillary angiomas, capillary malformations, captels) 2 nd most common CVM (10-20%) Pathology Dilated capillaries-normal intervening brain Brainstem most common (medulla / pons) Incidental and asymptomatic Essentially do not hemorrhage Can be solitary or multiple Angiographically occult Do not touch, no follow up

14 Capillary telangiectasias Imaging CT Usually negative May show mild hyperdensity, calcification, or enhancement MRI (choice) Unenhanced images often negative May have mild hyperintensity on T2/FLAIR images Signal loss on gradient echo or susceptibility-weighted MRI Mild contrast enhancement Angiography Negative No role for endovascular intervention MRI T1 without contrast MRI T1 with contrast MRI T2 MRI SWI

15 Cavernous malformations (aka cavernous angiomas, cavernomas, cavernous hemangiomas) Pathology Collections of blood filled caverns, no normal brain 50% calcify %/yr bleed risk 80% supratentorial 25-40% associated DVA Present 40-60yrs 0.5% population Gross appearance resembles a mulberry

16 Cavernous malformations Two forms: Sporadic 70-80% of cases More likely to have solitary lesions (~65-70%) Familial 20-30% of cases More likely to have multiple lesions (~70-75%) Lesions more likely to increase in size and number over time Highest incidence in families of Mexican descent 40% remain asymptomatic despite multiple lesions

17 Cavernous malformations Presentation and clinical features Asymptomatic (30-50%) Seizures (60%) Focal neurological deficits (up to 50%) Headaches (25-50%) Natural history May demonstrate spontaneous enlargement, regression, de novo formation, or remain unchanged with time Hemorrhage All lesions believed to undergo chronic microhemorrhages Typically bleed in small amounts, with episodes separated by months or years Symptoms may wax and wane with each bleed and resorption of blood products

18 Cavernous malformations Imaging CT Could be negative in small lesions May show hyperdensity related to calcification or hemorrhage May demonstrate mild or prominent enhancement MRI Imaging study of choice Mixed signal intensity on T1/T2 images surrounded by a black rim of hemosiderin ( popcorn appearance) Gradient echo sequences detect lesions with greater sensitivity Angiography Negative No role for endovascular intervention May be useful to exclude other vascular malformations if imaging is unclear CT FLAIR T2

19 Cavernous malformations Treatment options Conservative management Surgery If asymptomatic or only mild symptoms Surveillance imaging is an option Medical management geared towards seizure control Recurrent symptomatic hemorrhages Intractable seizures or other progressive neurologic deficits Surgically accessible lesions Stereotactic Radiosurgery Controversial, still under evaluation, but several small series and reviews have shown a benefit in rebleeding rates and seizure control May be an option for symptomatic lesions that are not accessible to surgery

20 Intermission Half way there Non- shunting (low flow) Developmental venous anomalies Capillary telangiectasias Cavernous malformations Shunting (high flow) Arteriovenous malformations Arteriovenous fistulas

21 High Flow SHUNTING LESIONS

22 Shunting lesions Types Arteriovenous Malformations Arteriovenous fistula Arteriovenous fistula

23 Arteriovenous malformations vs fistulas Both are abnormal connections between arteries and veins without an intervening capillary bed Essentially a short circuit in the vasculature, resulting in artery to vein shunting, or rapid flow of arterial blood into the venous system

24 What s the difference between an AV malformation and AV fistula? AVM: the transition from artery to vein takes place through an abnormal tangle of blood vessels called a nidus (Latin for nest ) AVF: direct connection between artery and vein without an intervening nidus

25 Arteriovenous malformations Pathology Gross appearance described as a snarl of tangled vessels, or a bag of worms Nidus may be compact or diffuse, and range in size from a few mm to entire hemisphere Functional brain tissue usually not present within a compact nidus, but may be present in diffuse lesions Gliosis, fibrosis, and calcification may be present in the adjacent brain parenchyma

26 Arteriovenous malformations Histopathology Arteries Abnormally dilated Degenerative changes due to high flow Prone to aneurysm formation There may be single or multiple feeding arteries Nidus Vessels may resemble arteries, veins, or be dysplastic May contain aneurysms and islands of sclerotic tissue Veins Arterialized and thickened due to high flow Venous aneurysms or varices may develop There may be single or multiple draining veins

27 Arteriovenous malformations Etiology Unclear, but felt to be congenital/developmental not genetic Felt to be dynamic lesions over lifespan Epidemiology Estimates of prevalence in the general population range from to 0.6% Slight male preponderance (55%) Mean age at diagnosis: 31 years Most AVMs are sporadic Related syndromes Familial intracranial AVMs (rare) Hereditary hemorrhagic telangiectasia (Rendu Osler Weber Syndrome) Wyburn-Mason Syndrome Sturge-Weber Syndrome

28 Arteriovenous malformations Natural history- Risk of AVM hemorrhage varies based on prior hemorrhage Without prior hemorrhage: 2-4% per year Not well understood With prior hemorrhage: Approximately 7% in first year after hemorrhage (although some studies report up to 17% in first year) Risk decreases to baseline after 3-5 years

29 Arteriovenous malformations Peak age for hemorrhage:15-20 yrs With each bleed: Mortality: 10% (5-30%) Morbidity: 20-30% Risk factors for hemorrhage Prior hemorrhage Smaller size Venous drainage Deep Single draining vein Impaired drainage (venous stenosis) Presence of aneurysms (15-25% have aneurysms) Deep or posterior fossa location

30 Arteriovenous malformations Clinical presentation Hemorrhage Sx- Seizures, HA, focality ICH 1-2 % of all ICH 3% in young adults SAH 9% all SAH IVH IVH Seizures (20-25%) Headaches (15%) Focal deficits / LD (Shunting<5%)

31 CT Arteriovenous malformations Imaging Non contrast CT MRI Will show acute hemorrhage May be negative for small, unruptured AVMs CT with contrast or CTA may show serpentine, enlarged veins and increased vascularity More sensitive than CT for subtle lesions Precise anatomic localization of lesions Post contrast CT Angiography Gold standard Greater sensitivity for small or subtle AVMs Defines anatomy of feeding arteries and draining veins Most sensitive study for detection of aneurysms

32 Arteriovenous malformations Angiogram

33 Arteriovenous malformations Management options Conservative management Surgery Stereotactic radiosurgery Embolization Combination Who to intervene on w/ hemorrhage clear Asymptomatic lesions less clear AVMs are complex lesions Need to take into account multiple variables before deciding on best treatment option for an individual patient *AVM Management Equipoise Survey: physician opinions regarding the management of brain arteriovenous malformations Kevin M Cockroft1,2,3, Ki-Eun Chang4, Erik B Lehman3, Robert E Harbaugh- J NeuroIntervent Surg ;2013

34 Arteriovenous malformations Who to treat. Multidisciplinary international randomized, controlled trial 800 adult patients with unruptured brain AVM Randomly assigned to prophylactic invasive therapy vs medical management Invasive therapy: endovascular, neurosurgical, and/or radiosurgery (alone or in combo) Follow for 5-10 years Primary endpoint Death from any cause Stroke (sx with imaging findings) Secondary endpoint: long term clinical status Mohr JP et al., Lancet Feb 15;383(9917):614-21

35 Arteriovenous malformation-aruba Randomization from April 2007 April 2013 Study stopped on recommendation of data and safety monitoring board appointed by NINDS/NIH because of superiority of medical management group 223 patients enrolled Mean follow-up 33.3 months Primary endpoint reached by 11 (10.1%) in medical management group vs 35 (30.7%) in interventional group

36 Arteriovenous malformation ARUBA-Limitations Length of follow up not long enough Unfairly biased toward procedural complications Not detect long-term benefits of prophylactic intervention Lack of standardization of treatment arm high risk lesions were selected out Did not control how patients treatments were selected Treatments should be tested individually to see merit Heterogeneous group Primary outcome of any sx stroke with imaging findings should be better defined (ie mrs>2)

37 Arteriovenous malformations Surgery Gold standard for treatment of small, accessible lesions Risk stratification using Spetzler- Martin grading system Timing of surgery after a bleed Early: Late: Clot has significant mass effect Lesion is surgically accessible Smaller clot burden If patient is a poor surgical candidate soon after the bleed Early imaging studies may not show AVM clearly / in total

38 Spetzler-Martin Grading Scale for AVMs Predicts surgical risk of AVMs

39 Surgical outcomes of AVMs Obliteration rates Spetzler-Martin Grades I-III: % Grades I-III account for 60-80% of all AVMs Grades IV-V: little data Complications Post-op mortality (death) Overall: 3.3% Grades I-III: 0-3.9% Grades IV-V: 11-38% Post-op morbidity(deficit) Overall: 8.6% Grades I-III: 0-5% Grades IV-V: 12-22%

40 Arteriovenous malformations Stereotactic radiosurgery Cyberknife Suite, Christiana Care, Newark, DE Involves delivering multiple beams of radiation, each from a different location All beams converge on the target, or iso-center Radiation dose high to the iso-center, but low to nontargeted structures

41 Arteriovenous malformations Stereotactic radiosurgery Advantages Minimally invasive Relatively low-risk Useful for treatment of surgically inaccessible lesions Disadvantages Most effective for smaller lesions (< 3 cm) Staged treatment can be considered for some larger lesions Latency period of about 2 years for AVM obliteration

42 Arteriovenous malformations Stereotactic radiosurgery outcomes Obliteration rates Lesions diameter < 3 cm: 75-95% Lesion diameter > 3 cm: </= 70% Complications Overall rate of neurological complications: 8% Radiation injury to brain: 6% Permanent neurologic deficits: 4.8% Radiation necrosis

43 Arteriovenous malformation Radiosurgery 28 year old female with severe headaches Worsening over time Intermittent left sided weakness

44 Arteriovenous malformation Radiosurgery MRI pre treatment Angiogram pre treatment AP image Lateral image

45 Arteriovenous malformation Radiosurgery 2yr Post Treatment MRI 2yr Post Treatment Angio

46 Treatment goals Risk Arteriovenous malformations Embolization Cure 5-10% cases Targeted therapy Hemorrhage risk / tx high risk features Adjunct to surgery or SRS Pre-surgical embolization Reduce volume of nidus Shorten operative time and blood loss Pre-SRS embolization Reduce volume of nidus If SRS does not obliterate AVM, repeat embolization can be performed Permanent morbidity: 2-14% Mortality: 1-3.7%

47 Arteriovenous malformation Endovascular Case 43 year old female with intractable headaches and medically refractory seizures No evidence of hemorrhage on NCCT MRI suggested AVM Diagnostic cerebral angiogram confirmed Treatment with Onyx Embolization

48 Arteriovenous malformation Endovascular Case- cure Pre Embolization Post Embolization Embolic Cast

49 Arteriovenous malformation Endovascular Case 55 year old male with sudden onset headache Evidence of hemorrhage on NCCT MRI suggested AVM Diagnostic cerebral angiogram confirmed high risk features Treatment with Onyx Embolization

50 Arteriovenous malformation Endovascular Targeted treatment

51 Arteriovenous malformation Endovascular Targeted treatment MRI without contrast

52 Arteriovenous malformation Endovascular Targeted treatment Angiogram

53 Arteriovenous malformations Conservative management Asymptomatic AVMs Large or difficult to treat lesions Patients at high risk of complications Sometimes okay to accept the risk of hemorrhage when the risk of treatment is too high

54 Arteriovenous fistula Occur anywhere along dura Direct communication Acquired lesions Trauma Surgery Post-partum Sinus thrombosis

55 Arteriovenous fistula 10-15% of all intracranial vascular malformations Peak presentation (M=F) Presentation depends on location and venous drainage Kiyosue; RadioGraphics 2004; 24:

56 Arteriovenous fistula- Risk

57 Arteriovenous fistual Poorly understood Prognosis depends on venous drainage 98% w/o CVD benign course With CVD aggressive course Hemorrhage Neurological symptoms Natural history

58 Arteriovenous fistula Treatment Who to treat Benign Pre treatment Only severe symptoms Malignant Secondary to high risk of bleed Embolization Mainstay of treatment Surgery adjunctive Cast Post treatment

59 Arteriovenous fistula Case 70 year old male with rapidly progressive dementia and Parkinson-like tremors Multiple trips to the ER Last ER visit became comatose (GCS 3) and was transferred as possible ETOH withdrawal

60 Arteriovenous fistula T2 Malignant T1 post gad

61 Arteriovenous fistula Angiogram Multiple bilateral feeders Occluded R transverse-sigmoid Retrograde filling of deep and superficial veins Embolized multiple branches Anterograde venous flow Resolution of symptoms Malignant

62 Summary Reviewed and classified the vascular malformations of the brain and discussed potential treatments Cerebral AVMs are complex, congenital lesions with a significant hemorrhage risk Cerebral AVMs may require a combination of embolization, surgery, and/or SRS for treatment Cerebral arteriovenous fistulas are acquired lesions that have risk from hemorrhage related to venous drainage and are treated with embolization primarily

63 Thank you!