Cerebral arteriovenous malformations Management and controversies associated with its management By Dr Shashank Mch resident,dept of Neurosurgery,Pt.JNM Govt Medical College n DKS PGI hospital Raipur

1. Management OF AVM
&
Controversies associated with its
management
By
Dr Shashank Nahar
MCh resident Neurosurgery

2. INTRODUCTION to AVM
• Harvey Cushing and Walter Dandy are credited with the modern conceptualization of cerebrovascular
malformations with both publishing reports in 1928.
• McCormick in 1966 and Russell and Rubenstein in 1971 described the four types of vascular
malformations and this is now accepted as the current nomenclature.
• Cerebrovascular malformations are classified based on their histopathologic features:
A. Arteriovenous malformation (AVM),
B. Venous angioma,
C. Cavernous malformation (CM) and
D.Capillary telangiectasia.
• A possible fifth category of cerebrovascular malformation includes direct fistulas or arteriovenous
fistulas (AVFs).

3. ARTERIOVENOUS MALFORMATIONS
Synonyms: arteriovenous fistulous malformation, pial arteriovenous
malformation, parenchymal arteriovenous malformation.
Definition
True AVMs are collection of dysplastic dilated intracranial vessels, which
consist of a number of direct connections between the arterial and venous
systems without an intervening capillary bed.

4. Epidemology
• Prevalence: 0.14%.
• Asymptomatic prevalence on brain MRIs: 0.05%.
• Incidence of detected asymptomatic or symptomatic AVMs: ≈ 1.3 per 1,00,000
person-years.
• Slight male preponderance.
• Comparison to aneurysms: the average age of patients diagnosed with AVMs is
≈ 33 yrs, which is ≈ 10 yrs younger than aneurysms.
• 64% of AVMs are diagnosed before age 40.

5. Pathology, Pathogenesis and pathophysiology
• AVMs are high-flow cerebrovascular lesions consisting of a tangle of abnormal blood vessels.
• Three morphologic features are typical of these lesions: feeding arteries, draining veins and a dysphasic
vascular nidus composed of a tangle of abnormal vessels that acts as a shunt from the arterial to venous system.
• Gross pathologic features include the absence of a capillary bed and the presence of small feeding arteries
composed of variable amounts of smooth muscle and elastic laminae with single or multiple direct
arteriovenous (AV) connections.
• The lack of a capillary bed results in low resistance and with the AV connections permits high-flow AV
shunting.
• Although the feeding vessels and draining veins themselves may not be congenitally abnormal, their
communication through the nidus subsequently leads to arterial dilation and venous arterializations.

6. Etiology
• AVMs may be classified as being sporadic or syndromic in origin.
1.Sporadic AVMs are most common.
• Although sporadic, there is increasing evidence that they occur as the result of upregulation or
downregulation of multiple homeobox genes, which are involved in angiogenesis such as HoxD320 and
HoxB3.
2.Syndromic AVMs account for approximately 2% of cases.
• Familial multiple AVMs are seen in hereditary hemorrhagic telangiectasia (HHT).
• Cerebrofacial arteriovenous metameric syndrome (CAMS) involves the face and brain.

7. AVM IN CHILDREN
• 3% to 20% of sporadic AVMs are diagnosed in children.
• AVMs are the most common cause of spontaneous brain hemorrhage in children.(excluding the neonatal
period).
• Bleeding is typically from rupture of a draining vein, associated with dilation, kinking and thrombosis or from
rupture of flow-related aneurysms which are more prevalent than in adults.
• Large AVMs generate an arterial steal phenomenon and older children may present with progressive
neurological deterioration and chronic epilepsy.
• If there is sufficient AV shunting, neonates and infants may present with congestive cardiac failure

8. Clinical presentation
1.They present primarily with hemorrhage (seen in approximately 65% of symptomatic lesions)-
{Intraparenchymal haemorrage is most common f/b Intraventricular f/b SAH}.
2. Seizures(15% to 35%)
3.The remainder present with Headache or Progressive neurological deficits.
• Headaches are common complaint in patients with AVM. Headache is typically located hemicranially
(ipsilateral or contralateral to the lesion) or the occipital region and the quality is similar to migrane.
• Consequently, mortality rates associated with AVM hemorrhage are approximately 6% to 29%.

9. Focal Neurological Deficits
• Less than 10% of patients will initially have transient, permanent or progressive focal
neurological deficits (FNDs) not ascribed to hemorrhage or seizure.
• Progression of neurological dysfunction may be a result of the long-term effects of
recurrent small hemorrhages, mass effect of the AVM, hydrocephalus or ischemic
complications and steal.
• Steal is the term used to describe blood flow away from a region of the brain toward
the shunt of the AVM. This flow may cause hypoperfusion, ischemia, and symptoms in
the region from where the blood was “stolen.”
• Consequently, steal may lead to focal or more global neurological deficits.
• Spetzler and coworkers hypothesized that the low feeding artery pressure associated
with large AVMs provides low perfusion pressure to the surrounding cortex, thereby
producing a relative ischemia.

10. IMAGING
1.Computed Tomography
• It is the primary neuroradiographic screening tool for patients presenting with
acute neurological symptoms related to unruptured or ruptured AVMs.
• A non-contrast CT may demonstrate the presence of acute hemorrhage,
hydrocephalus, calcification or areas of encephalomalacia related to previous
surgery or rupture.
• A contrast CT can provide information regarding the AVM location, nidus,
feeding arteries, and draining veins and is particularly valuable as a quick study
in the setting of a life-threating hemorrhage before surgical evacuation.

12. 2 Angiography
Cerebral digital subtraction angiography (DSA) is still considered the “gold
standard” to establish the diagnosis and to preoperatively assess a patient with
an AVM.
This study can provide valuable information regarding size, location, and
configuration (compact versus diffuse) of the AVM nidus as well as the pattern
and location of feeding arteries and draining veins
In addition, DSA may detect the presence of angioarchitectural features
associated with an increased risk for hemorrhage such as feeding artery or
intranidal aneurysms, deep venous drainage, venous aneurysm or outflow
compromise, perforating feeding vessels and deep or periventricular location.

13. 3.Magnetic Resonance Imaging
After angiography, magnetic resonance imaging (MRI) is the most important imaging modality
in the evaluation of an AVM.
• It is superior to CT in delineating the macroarchitectural details of the AVM as well as defining
its exact anatomic relation to the surrounding brain.
• An AVM typically appears as a tightly packed “honeycomb” of flow voids on T1- and T2-
weighted images.

15. • Secondary changes in the adjacent brain tissue, such as mass effect, edema, and ischemic changes, can
also be seen.
• MRI in conjunction with angiography provides complementary information that facilitates
understanding the three dimensional structure of the nidus, feeding arteries, and draining veins.
• On the other hand, magnetic resonance angiography (MRA) currently cannot replace conventional
cerebral angiography.
• Although MRI is sensitive in revealing subacute hemorrhage, in the setting of acute hemorrhage, it is
virtually useless because the hematoma obscures all details of the AVM.
• Author therefore recommend obtaining a formal cerebral angiogram in such cases if the clinical history
and the imaging characteristics of the hematoma suggest the presence of an AVM.

16. Staging, Grading or Classification Criteria
1.The Spetzler-Martin scale classifies AVMs according to size, location in relation
to functionally eloquent cortex and type of venous drainage.

17. 2.Lawton-Young,supplementary grading
scale for AVMs
The Lawton-Young (L-Y) supplementary
grading scale is a validated scale that
enhances the S-M grade.
This model is derived only using operated
AVMs and tended to be more helpful
when there was a mismatch with the S-M
grade:
• a S-M grade III with a low L-Y score
behave more like a S-M II AVM
• whereas a S-M grade III AVM with a
high L-Y grade AVM behaved more like
a S-M grade IV.

18. Therapeutic Decision Making in the Management of
Arteriovenous Malformations of the Brain
• Today, management decisions need to be based on an understanding of the
natural history as well as the risks and expectations of surgery, radiosurgery (or
focused irradiation) and embolization.
• The only randomized controlled trial (RCT)—the Randomised Trial of
Unruptured Brain Arteriovenous Malformations (ARUBA)—failed to identify the
outcomes from each of the management pathways (i.e., conservative
management, radiosurgery, embolization, surgery or a combination of these).

19. • Currently, the choice of action is among four management pathways:
A. no attempt at AVM obliteration
B. AVM resection by surgery
C. AVM thrombosis by focused irradiation
D. or AVM thrombosis by embolization—or a combination of these management
strategies.

20. Spetzler Ponce classification (SPC)
1.SPC Class A AVM (i.e., Spetzler-Martin grades I and II)
2.SPC Class B ( Spetzler Martin grade III AVM ) and
3.SPC class C is (Spetzler-Martin grades IV and V AVM).

21. Therapeutic decisions in the management of AVM
1.Conservative
• For the conservative management pathway, the risks are same as for the natural
history of AVM.
• Gross and Du in a meta-analysis of risk of future hemorrhage, concluded that the
annual rate of future hemorrhage was 2.2% for unruptured AVM and 4.5% for
ruptured AVM.

22. • Gross and Du concluded that previous hemorrhage, deep location, exclusively
deep venous drainage and associated aneurysm were statistically significant
factors increasing the risk of subsequent hemorrhage.
• Kim and colleagues reported a lower risk of rupture for unruptured AVM with
an annual first hemorrhage rate of 1.3% and 4.8% for ruptured AVM(Similar to
Gross n Du).
• Greater risk of rupture detected in older patients in the report by Kim and
colleagues, which questions the finding of an increased risk with age.

23. • A lack of effect of age is suggested by the observation that the most common
adult presentation occurs in the 25- to 55-year age group and by the fact that
the risk of rupture from birth to diagnosis is similar to that from diagnosis to
intracranial hemorrhage (ICH).
• For the purpose of decision making author has considered upper and lower
95%CI from Gross n Du’s meta-analysis for ruptured and unruptured AVM and
he found that the risk of next rupture for ruptured AVM is 3.7% to 5.5% for
the first 5 years but beyond 5 years,it is the same as for unruptured AVM.

24. • Factors that increase the likelihood of rupture of unruptured AVM include the
presence of aneurysms, deep location (or exclusively deep venous drainage)
and age (possibly).
• Size should not be considered a risk factor.
• The risk of death from the first hemorrhage ranges from 3% to 58% and the
combined morbidity and mortality is reported to range from 35% to 89%.

25. 2.Focused Irradiation Radiotherapy
• This modality became effective for many AVMs.
• Focused irradiation needs to include the risks of radiation-related complications.
• The tolerance of normal brain to withstand damage is severely tested above 10 Gy.
• These risks are interactive if one is to achieve a desired delivery of at least 20 Gy to
the AVM to induce thrombosis.

26. • Approximate volume is obtained by multiplying three diameters of the AVM and
dividing by 2:
• The surgical grading system is very useful to enable a comparison of outcomes
between focused irradiation and surgery.
• Kano and colleagues found that approximately 87% of SPC class A AVMs with
maximum diameter less than 2 cm were obliterated after radiosurgery over 5
years compared with larger diameter SPC class A AVMs, approximately 67% of
which were obliterated over the same period of time.

27. • SPC class B AVMs can be successfully treated by focused irradiation with an obliteration rate of around 50% at 3
years and 70% at 5 years (including those undergoing repeat radiosurgery).
• The best obliteration rate is in small AVM(<3 cm) with no prior embolization. The presence of aneurysms
increases the likelihood of hemorrhage during the latency period.
• Effectively treating larger AVMs with focused irradiation is much more difficult.
• Repeat focused irradiation can be performed and has a reported obliteration rate of 35% and 68% at 3 and
4 years after the repeat treatment.
• Planned staged volumetric reduction (with repeat focused irradiation for residual AVM) has been reported for a
small number of cases.
• Focused irradiation should be done only after consideration of alternative management pathways (including
conservative management).

28. 3.Embolization
• Embolization with ethylene vinyl acetyl copolymer is increasing in popularity as the agent
used for either attempted curative treatment or as an adjunct to treatment by other
methods.
• The results of ARUBA( the only RCT for the management of unruptured AVM) suggest that
a. the role of embolization in unruptured AVM is questionable if alternate management
options are reasonable. (because the treatment related complications is critical)
b. Embolization in ruptured AVM may have a greater role than in unruptured AVM.

29. • The multimodality use of embolization have combined risks of embolization
and the subsequent treatment which may have greater risk than the risk of
single treatment in the absence of embolization.

30. ARUBA AND THE DEBATE ABOUT UNRUPTURED ARTERIOVENOUS
MALFORMATIONS
• In 2014, the findings of A Randomized trial of Unruptured Brain Arteriovenous
malformations (ARUBA) were published.
• The study was a comparison of the risk of death and symptomatic stroke in
patients with unruptured AVMs who were randomly assigned to receive either
(medical management) or (medical management with interventional therapy).
• The study enrolled 226 patients between 2007 and 2013, and the mean follow-
up period was 33.3 months.
• The investigators concluded that the risk of stroke or death was lower in the
patients who received only medical management (10.1% versus 30.7%).

31. The design and implementation of this trial have been significantly criticized on three main points:
(1) only 223 (13%) of 1740 screened patients were studied
(2) Although 76 (68%) of the 112 patients randomly assigned to receive intervention had low-grade AVMs, only
18 patients underwent surgery; and
(3) the short follow-up period of 33 months inherently favors the outcome of medical management, in as much
as the curative effects of interventional treatment would take effect over longer periods of time.
Of importance is that the vast majority of patients who received intervention underwent embolization or
radiosurgery, both of which had lower obliteration rates than did surgical resection.

32. • Rutledge and associates reported the treatment and outcomes of all ARUBA-eligible
patients managed at the University of California, San Francisco, between 2007 and 2013.
• Rutledge and associates’ ARUBA-eligible patients had better outcomes than those
reported in the ARUBA trial, and they attributed this difference to their multidisciplinary
approach, in which they considered surgery to be the primary therapy.

33. • In support of the ARUBA conclusions, the Scottish Audit of Intracranial Vascular
Malformations performed a population based observational cohort study of
204 patients in whom an AVM was diagnosed.
• Of those patients, 103 underwent intervention alone or in combination.
Outcomes were compared between the two groups at 4 years and after 4 years.
• The investigators found that the rate of the primary outcome (death or
sustained morbidity) was worse among the intervention recipients at 4 years
but equal in the two groups after 4 years.
• They also found that the rate of the secondary outcome (nonfatal symptomatic
stroke or death from the AVM, associated aneurysm, or intervention) was worse
among the intervention recipients at all time points.

34. • This study is weakened predominantly by its design as a nonrandomized, observational
cohort study.
• Despite the ARUBA trial and the conclusions of the Scottish observational study, the debate
over the best management for AVM patients continues.
• Most neurosurgeons agree that because of the heterogeneity of brain AVMs, the data must
be applied generally and judgment should be used in each particular case to determine
which treatment, or whether none, would be beneficial for an individual patient.
• A treatment plan should be determined by a multidisciplinary team(that includes a
neurologist, a neurointerventionalist, a radiation oncologist, and a cerebrovascular
neurosurgeon).
• In the majority of cases, endovascular embolization is the first-line treatment with the goal
of decreasing the size of the nidus or the number of arterial feeders.
• The role of endovascular embolization is expanding because of the development of better
embolic agents, catheters and techniques— may be curative in patients with certain lesion
characteristics.

35. FACTORS ASSOCIATED WITH ENDOVASCULAR MANAGEMENT AS CURE
1.Size
In the earliest investigators noted success in AVMs larger than 3 cm, however
more recent studies have clearly identified small size as a favorable factor in
attaining cure.
Pierot and colleagues in 2013 reported that, out of total 61 AVMs smaller than
3 cm, 23 (37.7%) were 100% occluded,
whereas only 4 (7.5%) of 53 AVMs larger than 3 cm were successfully occluded.

36. 2.Location
Endovascular embolization reaches a higher cure rate in superficial lesions
located in non-eloquent areas.
3. Morphologic Features
AVMs with fewer, larger and less tortuous feeding arteries are more amenable
to cure with embolization.
4.Patient-Specific Factors
Smoking has been associated with a lower rate of obliteration after treatment
In summary, characteristics that are correlated with endovascular cure include
small size, superficial location, non-eloquence of the location and large non-
tortuous feeding arteries of the AVM, as well as being a nonsmoker.

37. COMPLICATIONS OF ENDOVASCULAR TREATMENT
Permanent neurological injury, are reported in 5% to 15% of cases.
The risk of embolization-related death in particular seems to average about 1%.

38. Role of Adjuvant Endovascular Management of Brain
Arteriovenous Malformations
• Therapeutic decision making regarding the need for adjuvant endovascular treatment of brain AVMs is complex
and should be done by a multidisciplinary team.
• The specific treatment goals must be designated in each case by taking into account the clinical presentation of
the patient as well as the angioarchitecture and location of the AVM.
• Some have suggested that low–Spetzler-Martin grade AVMs need not be embolized before surgery, exceptions
inevitably exist.
• Indeed, adjuvant endovascular embolization may eliminate deep arterial feeders from low-grade lesions, making
surgical resection safer, it may effectively shrink high-grade lesions, making them more amenable to
radiosurgery or microsurgery.

39. • AVM-associated aneurysms are a major target for adjuvant endovascular treatment because the morbidity and mortality
associated with aneurysm rupture or re-rupture is significantly higher than for the AVM itself.
Embolic agents
1. Liquid
• The liquid embolic compounds n-butyl cyanoacrylate (Trufill) and ethylene vinyl alcohol copolymer (Onyx) are the most
commonly used agents for the embolization of brain AVMs.
• Both have been approved by the U.S. Food and Drug Administration (FDA)—Trufill in 2000 and Onyx in 2005—for the
presurgical embolization of brain AVMs.
• Although these agents are considered permanent embolic agents, AVM recanalization after “complete” angiographic
occlusion has been reported for both.
• Onyx precipitates and solidifies more slowly than NBCA.

40. 2.Nonliquid
The particulate embolic agent polyvinyl alcohol (PVA) and platinum coils are less commonly
used now for the embolization of AVMs.
PRE-MICROSURGICAL EMBOLIZATION
• Adjuvant pre-microsurgical embolization is the most widely accepted role for endovascular
therapy in the management of brain AVMs.
• Early reports beginning in the 1970s suggested that preoperative embolization facilitated the
surgical resection of AVMs.
• The objectives of AVM pre-microsurgical embolization may include the obliteration of so-
called angioarchitectural “weak spots” that can increase morbidity before or during
resection, the occlusion of deep arterial feeders that are less accessible after craniotomy
and the global reduction of arteriovenous shunting.

41. • Preference for staged versus single session preoperative embolization is
similarly practitioner dependent and the usefulness is not confirmed by
evidence-based literature.
• It is still unclear whether the overall risk of multimodality treatment for a
particular AVM treatment is constant, endovascular specialists and surgeons
should communicate and predetermine the specific goals of each intervention.

42. PRE-RADIOSURGICAL EMBOLIZATION
• Although pre-radiosurgical embolization is a recognized adjuvant strategy for
the treatment of brain AVMs, it is less widely accepted than pre-microsurgical
embolization.
• In general, pre-radiosurgical embolization may be performed with the
objectives of volume reduction, latency period risk reduction, and/or the
elimination radioresistant features

43. • Permanent volume reduction is attempted for large AVMs, typically those
greater than 3 cm in largest dimension or 10 mL in volume, in order to increase
the safety and effectiveness of radiosurgery.
• Whereas small AVMs are routinely obliterated by radiosurgery at rates in excess
of 70%, much lower rates of obliteration are observed for large AVMs.
• With use of a strategy of pre-radiosurgical embolization for large AVMs,
obliteration rates in excess of 60% have been reported.

46. 4.Surgery
The significant difference between the low–surgical risk (Spetzler-Martin grades below III
and the high– surgical risk grades above III )stratifies the Spetzler-Martin grading system
into three groups (the SPC):
• SPC class A(Spetzler-Martin grades I and II with a low risk of surgery).
• SPC class B (Spetzler-Martin grade III with an intermediate risk).
• SPC class C, (Spetzler-Martin grades IV and V with a high and usually prohibitive risk
of surgery).

47. This correlates with a reported risk of a less than
• 10% adverse outcome rate for SPC class A
• 18% for SPC class B and
• more than 30% for SPC class C.
In a number of series, the long-term adverse outcome risk for SPC class A is no
greater than 4%.

48. • Apart from size, location, and deep venous drainage to the Spetzler-Martin
grade, other factors have been identified to modify the risk.
• Diffuse nidus a risk factor for new postoperative deficits has led to the
development and validation of a new grading system, the Lawton Young
grade.
• This results in a range of Lawton-Young scores of 2 to 10.
• This has been validated by Lawton and colleagues and across four
independent sites.

49. • The results of the Lawton-Young scale have the greatest impact on decision
making for SPC class B AVM.
• For unruptured Spetzler-Martin grade II AVM (SPC class A) in patients older
than 40 years with diffuse nidus (Lawton-Young score of 7), the adverse
outcome risk was found to be about 40% by surgery in the validation combined
series.
• This would suggest that similar cases may best be managed by an alternate
pathway.

50. • In a similar way, the risks of surgery for SPC class C cases is very high, and
nonsurgical management pathways are usually recommended for affected
patients.
• However, for ruptured Spetzler-Martin grade IV cases (therefore, SPC class C)
in patients younger than 20 years with compact nidus (Lawton-Young score of
4), the adverse outcome risk was found to be 10% in the validation combined
series. This would suggest that these patients may be managed by surgery.
• The Lawton-Young scale has a significant impact on predicted risk for SPC class
B with an approximately 10%, 20%, 25%, 40%, and 65% adverse outcome risk
for Lawton-Young score of 4, 5, 6, 7, and 8 respectively.
• Preoperative embolization is a common adjunct to surgery and is highly
variable, both in extent of embolization and vessels targeted.

51. • Two common strategies are employed to reduce intraoperative hemorrhage:
a.embolization of feeding vessels that are difficult to access by surgery (e.g.,
posterior cerebral artery) for early proximal control and
b.embolization of the nidus to reduce the effective volume.
The protocol used in selecting the management pathways is provided in Figure
402-6.

53. Combined Treatments
• A common, well-accepted combined treatment is preoperative embolization
followed by surgical resection.
• For other combined treatments (e.g., embolization followed by focused
irradiation, multistaged focused irradiation, embolization followed by focused
irradiation followed by surgery) evidence from prospective intention-to-treat
studies is limited.
• However, two such studies do assist us in formulating a limited view: Kano and
colleagues who studied multi-staged radiosurgery for large AVMs and the RCT
ARUBA for unruptured bAVM.

54. • ARUBA was dominated by combined treatments (the most common being
embolization followed by focused irradiation).
This study found treatment (presumably applicable to the combined treatments) to be
worse than no treatment in unruptured bAVM.
• Kano and colleagues demonstrated that planned multistaged treatment with
focused irradiation resulted in more deaths in the small number of cases in the
treated group than cures in the treated group.

55. • Multimodality or staged treatment (with the exception of some surgical case series that
included preoperative embolization) may fail to prove better and is very weakly evidence
based.
• Evidence from prospective studies fails to support intervention.
• If a reasonable option for treatment is available by monotherapy (including preoperative
embolization) this is likely to be preferable and more likely to have a higher level of
evidence for its support.
• A conservative management pathway may prove to be a better option if multistaged and
multimodality treatment is considered to be the only option available for the patient.

56. OTHER FACTORS CONSIDERED IN MANAGEMENT DECISIONS
A. Epilepsy
• There are no RCTs investigating the outcomes after different modes of
treatment.
• A meta-analysis of retrospectively analyzed case series concluded that
complete seizure control after surgery in patients with pretreatment seizures
can be achieved in the majority of patients.
• Although surgery (with or without preoperative embolization) appeared to
achieve the best results (with 78% seizure control in comparison with 63% for
focused irradiation and 49% for embolization), there are clearly different AVM
in each of the management strategies, making comparisons inappropriate.

57. • New onset of seizures in patients with no preoperative seizures was reported
for each of these management strategies to be 9% for surgery, 39% for
embolization and 5% for focused irradiation.
• The recommendation that intervention be performed for seizure
management should be considered only if a regimen of dual antiepileptic
medications, properly administered and supervised fails to control intractable
disabling seizures.

58. • Preventing early postoperative seizures is particularly appropriate after AVM
surgery because of the potential for blood pressure increases during seizure
activity.
• Loading of antiepileptic drugs during surgery or preoperatively is appropriate.

59. B.Timing of Early Postoperative Radiologic Imaging
• To reduce the risk of postoperative hemorrhage, there is a need to know as soon as possible whether
residual AVM exists after surgery.
• Ideally this would occur during surgery and any residual AVM would be treated immediately.
• The use of indocyanine green and intraoperative angiography can assist with improving confidence
that the AVM has been resected.
• However, it is possible that residual AVM exists despite negative digital subtraction angiography
(DSA). This can occur when a residual AVM nidus remains with all its venous outflow occluded. With
the inability for blood to exit the residual nidus, contrast will fail to enter.

60. • The dangerous situation of non-resected stagnant non-thrombosed nidus, may
account for some instances of postoperative intracerebral hemorrhage.
• It may be better to perform the DSA, 1 week after surgery with respect to
completeness of resection.
• It is likely at 1 week that stagnant nidus flow at the time of surgery would have
either thrombosed or have reestablished arteriovenous shunting and thus be
visible.
• It is very important that attention be given to the late venous phase because
the large redundant arteries may fill much more slowly.
• An advantage of DSA at 1 week is that significant remodeling of the proximal
arteries will have occurred.

61. • For large-flow AVMs, it is importance to guide the planned relaxation of
the blood pressure controls (if blood pressure control has been deemed
necessary) that may have been instituted to reduce the risk of postoperative
delayed hemorrhage.
• CTA is also a useful technique to ascertain the presence of residual AVM.

62. • The author current practice is to use intraoperative ICG and early (immediate if
concerned or the next morning if less concerned) computed tomographic angiography
(CTA).
• If CTA findings are reassuring, then DSA is performed at 7 days.
• If the early CTA raises the suspicion of residual AVM, DSA is performed immediately.
• If residual AVM is identified, surgery is performed at that time.

63. C. Intensive Care Unit Management of Patients with Arteriovenous Malformation of
the Brain after Surgical Resection
• Brain hemorrhage during and after resection of AVM is a potentially catastrophic
complication (more likely to occur with larger lesions).
• The underlying mechanism involves a rise in intravascular pressures.
• This can occur as a consequence of venous outflow occlusion, a failure of
autoregulation (normal perfusion pressure breakthrough) or a rise in pressure
within proximal arteries with insufficient integrity because of chronically low
pressures.
• Collectively, hemorrhage from these problems can be called arterio-capillary-venous
hypertensive syndrome.
• Remodeling of the arteries over time (because of the reduction in endothelial nitric
oxide synthase (eNOS) and an increase in pulsation increasing endothelin release)
will return the intravascular pressures to normal.

64. • Blood pressure should be vigilantly controlled until sufficient remodeling has occurred within
the arteries.
• For larger AVMs, this may require active blood pressure reduction to levels known to be safe
for normal brain but significantly lower than normal.
• This has been demonstrated to reduce the risk of postoperative hemorrhage.
• This strategy of blood pressure control is unlikely to be necessary for most SPC class A or
smaller SPC class B AVMs.

65. • Arterio-capillary-venous hypertensive syndrome is not the only problem
that needs to be considered after resection of large AVMs.
• Vasospasm can occur with devastating consequences. For patients who
require therapeutic hypotensive therapy, prophylaxis against vasospasm is
reasonable to attempt.

66. • The senior author manages large AVMs in the intensive care unit with
intravenous calcium channel blockade (with nimodipine and/or magnesium);
this is also useful in inducing the desired effect of supplementing blood
pressure control to reduce the risk of arterio-capillary-venous hypertensive
syndrome with a possible protective effect against the development of
vasospasm.

67. D. Surveillance Radiology
• Both residual AVM and recurrence should be considered a possibility.
• The likelihood of recurrence in the absence of arteriovenous shunting, in the absence
of angiomatous vasculature in adults undergoing resection, is very small.
• However, for young patients (<20 years of age) with deep venous drainage, the
chance of recurrence is likely to exceed 20% over a 5-year period.

68. • In the presence of persisting angiomatous vasculature on postoperative angiography, surveillance is
necessary because this can progress to arteriovenous shunting with time.
• If the CTA or MRI or MRA study is of sufficient quality and residual AVM or recurrence can confidently
be eliminated, no need to perform late DSA.
• If AVM cannot be excluded, then a DSA is performed.
• For patients who have undergone AVM resection in which arteriovenous shunt ablation has been
confirmed, who are younger than 20 years or who have angiomatous vasculature, annual CTA or MRI
or MRA is appropriate, with subsequent DSA if these studies fail to exclude AVM.

69. E. Pregnancy and Arteriovenous Malformation of the Brain
• ICH during pregnancy is a significant contributor to maternal mortality.
• AVM accounts for a significant proportion of such hemorrhages.
• Early series reporting on the association between AVM and hemorrhage during
pregnancy and concluded that there was an increased risk of rupture of AVM during
pregnancy.
• These reports led to a common practice of recommendations: AVM obliteration
before pregnancy, avoidance of vaginal delivery or prevention of pregnancy.
• However, the evidence for such recommendations is limited.
• However, all studies are retrospective with small numbers, and management of
cases reported may have been influenced by earlier studies.

70. F. Acute Intracranial Hemorrhage and Arteriovenous Malformation of the Brain
• The management of acute ICH with AVM should be determined by the normal decisions with regard
to ICH.
• Whether to remove AVM at the time of hematoma evacuation should be determined by the
surgeon’s comfort level for AVM resection.
• However, partial AVM resection is ill advised.
• Immediate surgery is appropriate without DSA.
• If DSA has revealed an SPC class A or compact SPC class B AVM and the surgeon is comfortable with
proceeding, it is reasonable to combine the emergency evacuation with definitive AVM resection.
• However, If the AVM is complex and/ or the surgeon inexperienced, a delay between the
evacuation of the hematoma and obliteration of the AVM would be advised.
• It should be kept in mind that neurological deficits may recover and surgery should not be performed
assuming that any loss of function present acutely allows greater freedom for adjacent brain removal.

71. G. Concomitant Aneurysm
a.Unruptured Arteriovenous Malformation of the Brain and Unruptured Aneurysm
• The presence of a pre-nidal or intranidal aneurysm in an unruptured AVM likely
increases the risk of rupture.
• Da Costa and Brown report this risk to be about 7% per year.
• Increased risk of rupture is likely based on the principle that these aneurysms
represent a state of vascular degeneration from the hemodynamic stress
consequent to the high shear stress induced by arteriovenous shunting.

72. Aneurysmal Subarachnoid Hemorrhage and Arteriovenous Malformation of
the Brain
• When an aneurysm on a feeding artery ruptures in association with an
unruptured AVM (intranidal aneurysm rupture should be considered a AVM
rupture), management should be similar to the treatment of an aneurysm in
absence of AVM.
• Vasospasm may be less likely to occur in the dilated feeding arteries feeding
the AVM with a thin media.

73. • However, resection of the AVM within the vasospasm period may compound
the effect of vasospasm with the anticipated remodeling of the feeding artery
associated with vasospasm.
• With a dramatic reduction in arterial remodelling, vasospasm may be
exacerbated.
• Furthermore, the reduced flow in the territory from vasospasm may also affect
the capacious venous drainage system to induce venous stasis and infarction.
• Therefore, it would be wise to postpone management of the AVM until after
the period of vasospasm has elapsed.

74. Ruptured Arteriovenous Malformation of the Brain and Unruptured Aneurysm
• In this scenario, the AVM and aneurysm management should be as for
ruptured AVM and unruptured aneurysm, taking into consideration the
greater risk of AVM re-rupture discussed earlier in the section on conservative
management.
• There is greater priority to manage the AVM in this case if the aneurysm is
small, round, and smooth. If the aneurysm can be treated with the same
exposure, then both aneurysm and AVM should be treated with one
craniotomy.
• If a separate approach is deemed appropriate and the aneurysm would be
at risk of rupture during surgery because of pressure rise, then the aneurysm
should be repaired before AVM surgery.
• How it should be repaired should take into account that antiplatelet
medications will be contraindicated in the treatment of the aneurysm because
of the ruptured AVM.

75. • Unruptured Arteriovenous Malformation of the Brain and Ruptured Aneurysm In this scenario,
priority is given to the aneurysm rupture, and surgery for the AVM is normally contraindicated
during the vasospasm period.
• The danger of compounding the difficulties of management (e.g., conflict between desired blood
pressure regimens of the aneurysm repair and AVM resection) with those of physiologic changes (e.g.,
the potential for venous infarction with reduced cerebral blood flow if vasospasm were to occur in the
presence of a lower than normal velocity of flow in a dilated venous system after AVM resection)
suggests that combined treatments should be considered only after thoughtful evaluation.

76. SUMMARY OF MANAGEMENT RECOMMENDATIONS
1. Spetzler-Ponce Class A
• The preferred option for most patients with SPC class A AVM is surgery, providing they have
an expected good quality of life of more than a few years without significant comorbidities.
• The risks for surgery are generally low.
• The exception is for diffuse Spetzler-Martin grade II, unruptured AVM, in those older than
40 years, the Lawton-Young scale would suggest that permanent morbidity from surgery
occurs in 55% to 70% of such patients.

77. • Although these AVMs may be difficult to target with radiosurgery, this may prove to be
a reasonable option in patients with a Pollock-Flickinger score of less than 2.5.
• Given the nature of AVMs that cannot be treated by surgery or radiosurgery, few of
these patients need to be considered for endovascular procedures.
• However, in the rare case in which hemorrhage has occurred but cure of the AVM is
deemed inappropriate (and aneurysms are present), targeted embolization of
arteries with aneurysms that are thought to be the site of rupture may be
considered.

78. 2.Spetzler-Ponce Class B
Of all groups, SPC class B poses the most challenging decision making.
To manage these AVMs, knowledge of all the risks, expectations and alternatives must be
current.
The role of the Lawton-Young grading system may be particularly pertinent to this group of
patients.
• For ruptured AVM, surgery is likely to be the best option for those younger than 40 years
and for patients at any age with a compact AVM.
• For unruptured AVM, surgery offers the most effective way of avoiding future hemorrhage.
However the risk are considerably greater than for SPC class A.
• For unruptured SPC class B AVM in patients older than 40 years or those with diffuse AVM
who are older than 20 years, Radiosurgery is appropriate( If Pollock-Flickinger score is less
than 2.5).

79. • Conservative treatment is a reasonable option for patients with unruptured
SPC class B AVM who are unsuitable for surgery or radiosurgery.
• At this point in time, embolization is unlikely to be superior to conservative
management given the results of ARUBA.

80. C.Spetzler-Ponce Class C
• First, do not harm.
• In general, these patients should not be treated.
• For unruptured SPC class C AVM, exceptions can be made for the young(< 40 yrs) or
those with disabling, poorly controlled seizures based on anecdotal evidence who
are willing to consider the likely “trade” for a permanent neurological deficit.
• For ruptured AVM, some might be considered suitable for treatment. However, the
decision is very nuanced.
• Patients older than 40 years is unlikely to be a benefit.
• Combining treatments may be worse than the natural history.
• The justification for treatment in these cases needs to be carefully considered.

81. THANK YOU