Intracranial Vertebral Artery Dissection Dr Mat Bateman, Dr Danus Ravidran, Dr Ayton Hope, Dr...
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Intracranial Vertebral Artery Dissection Dr Mat Bateman, Dr Danus Ravidran, Dr Ayton Hope, Dr Maurice Moriarty, Dr Stefan Brew, Dr Ben McGuinness Auckland
Intracranial Vertebral Artery Dissection Dr Mat Bateman, Dr
Danus Ravidran, Dr Ayton Hope, Dr Maurice Moriarty, Dr Stefan Brew,
Dr Ben McGuinness Auckland City Hospital, Auckland, New
Zealand
Slide 2
Introduction Intracranial vertebral artery dissection (iVAD) is
a rare condition but one which is increasingly recognised as a
cause of morbidity and mortality in younger patients. (1,2,3)
Intracranial vertebral artery dissection (iVAD) is a rare condition
but one which is increasingly recognised as a cause of morbidity
and mortality in younger patients. (1,2,3) It can occur
spontaneously or be related to trauma (4) It can occur
spontaneously or be related to trauma (4) Vertebral artery
dissecting aneurysm (iVAD) can result in rupture and subarachanoid
haemorrhage (SAH) (3) Vertebral artery dissecting aneurysm (iVAD)
can result in rupture and subarachanoid haemorrhage (SAH) (3) Due
to the risk of haemorrhage, management of iVAD can be challenging
(5) Due to the risk of haemorrhage, management of iVAD can be
challenging (5)
Slide 3
Epidemiology Initially thought to be rare however iVAD is being
increasing described as a cause of SAH (6). Initially thought to be
rare however iVAD is being increasing described as a cause of SAH
(6). The exact incidence of iVAD is unclear (2) The exact incidence
of iVAD is unclear (2) iVAD represents approximately 2% of
intracranial aneurysms (7) iVAD represents approximately 2% of
intracranial aneurysms (7) A slight male predominance is described
with the most common age group being 30 - 50 year olds (3) A slight
male predominance is described with the most common age group being
30 - 50 year olds (3) Hypertension is thought to be the most common
modifiable risk factor. Other risk factors include minor trauma,
oral contraceptive pill, migraine, or intrinsic disorders of the
vessel wall (2,7) Hypertension is thought to be the most common
modifiable risk factor. Other risk factors include minor trauma,
oral contraceptive pill, migraine, or intrinsic disorders of the
vessel wall (2,7)
Slide 4
Pathophysiology The vertebral artery consists of 3 layers; the
intima, media and adventitia. (2,7) The vertebral artery consists
of 3 layers; the intima, media and adventitia. (2,7) The intradural
vertebral artery has much thinner media and adventitial layers with
little or no elastic fibers compared to the extradural artery. (8)
The intradural vertebral artery has much thinner media and
adventitial layers with little or no elastic fibers compared to the
extradural artery. (8) Intracranial dissection usually disrupts
both the intima and media. False aneurysms can occur when the
subadventitia is disrupted. (2,7) Intracranial dissection usually
disrupts both the intima and media. False aneurysms can occur when
the subadventitia is disrupted. (2,7) Rate of re-rupture in
ruptured aneurysms is as high as 70%. Re- rupture is most likely to
occur early in the clinical setting (2,7,9) Rate of re-rupture in
ruptured aneurysms is as high as 70%. Re- rupture is most likely to
occur early in the clinical setting (2,7,9)
Slide 5
Clinical Presentation The most common presenting symptom of
vertebral artery dissection is severe occipital headache (5,10).
The most common presenting symptom of vertebral artery dissection
is severe occipital headache (5,10). TIA or ischemia can either
from occlusion of local perforators resulting in lateral medullary
dysfunction or from distal embolism (9) TIA or ischemia can either
from occlusion of local perforators resulting in lateral medullary
dysfunction or from distal embolism (9) Aneurysmal dilatation can
lead to rupture and subsequent SAH Aneurysmal dilatation can lead
to rupture and subsequent SAH It is important to recognise that the
same pathology may present with either haemorrhage or ischemia. If
iVAD is diagnosed within hours to days after onset it is difficult
to know which of these two clinical scenarios will potentially
unfold It is important to recognise that the same pathology may
present with either haemorrhage or ischemia. If iVAD is diagnosed
within hours to days after onset it is difficult to know which of
these two clinical scenarios will potentially unfold
Slide 6
65 year old male presents with sudden occipital headache after
exercise. CT and LP was negative for subarachnoid haemorrhage. No
abnormal vascular density is seen about the intradural vertebral
arteries in retrospect
Slide 7
3 days later he collapses. CT on admission showed large
extensive subarachnoid haemorrhage. CTA demonstrated an irregular
sidewall aneurysm of the intradural right vertebral artery (red
arrow) thought most likely to be a dissecting aneurysm. Patient
died as a result of the hemorrhage.
Slide 8
Late Presentation Delayed presentation of iVAD may be as an
incidental fusiform aneurysm Delayed presentation of iVAD may be as
an incidental fusiform aneurysm There are other possible causes of
fusiform vertebral artery aneurysms and it is often not possible to
determine the cause: atherosclerosis, disorders of collagen or
elastin (e.g. FMD), rarely invasion of vessel wall by infection or
tumour (e.g. left atrial myxoma) There are other possible causes of
fusiform vertebral artery aneurysms and it is often not possible to
determine the cause: atherosclerosis, disorders of collagen or
elastin (e.g. FMD), rarely invasion of vessel wall by infection or
tumour (e.g. left atrial myxoma)
Slide 9
Incidental Finding Small fusiform aneurysm of the intradural
right vertebral artery (red arrows) in a 50 year old female who
underwent MRI for two episodes of hemisensory disturbance. The
presumed dissecting aneurysm was thought incidental and was stable
in size on 3 years of follow up.
Slide 10
Imaging Findings Sequalae of iVAD such as SAH or ischemic
changes are the most common imaging findings on CT imaging.
Sequalae of iVAD such as SAH or ischemic changes are the most
common imaging findings on CT imaging. MRI Cresenteric shaped
intramural haematoma (especially when T1 hyperintense). This may be
difficult to identify in the setting of coexistant subarachnoid
hemorrhage. (5) MRI Cresenteric shaped intramural haematoma
(especially when T1 hyperintense). This may be difficult to
identify in the setting of coexistant subarachnoid hemorrhage. (5)
Angiographic appearances CTA and MRA can be used but catheter
angiography is often required (5,9) Angiographic appearances CTA
and MRA can be used but catheter angiography is often required
(5,9) - Occlusion with vessel expansion - Focal stenosis
(nonspecific without MRI findings) - Fusiform aneurysm often with
stenotic change proximal or distal to the aneurysm It is important
to note that imaging diagnosis is challenging and potentially
subjective. It is important to note that imaging diagnosis is
challenging and potentially subjective.
Slide 11
Angiographic Findings Two different cases showing typical
fusiform aneurysmal change (red arrow) with proximal stenosis
(yellow arrow) of iVAD. Similar findings can be seen on CT
angiography although they are often more subtle
Slide 12
Challenging Case 55 year old male presents with collapse GCS 6.
CT shows posterior fossa predominant SAH CTA showed no clear source
of the hemorrhage MRI showed focal hematoma (red arrow) about the
intradural left vertebral artery (yellow arrows) associated with an
acute left PICA infarct Cerebral angiography shows subtle
irregularity of the intradural left vertebral artery with
associated contrast stasis (red arrows). The left PICA is absent
and likely occluded (hypoplastic left AICA). This was treated with
coil occlusion
Slide 13
Management - Unruptured Unruptured iVAD represent a diagnostic
challenge due to the potential risk of haemorrhage however studies
have shown that aneurysms that are unruptured at the time of
presentation have a low chance of subsequent rupture (9) Unruptured
iVAD represent a diagnostic challenge due to the potential risk of
haemorrhage however studies have shown that aneurysms that are
unruptured at the time of presentation have a low chance of
subsequent rupture (9) In these patients, the prevention of
ischemia is paramount, therefore anticoagulation or antiplatelet
medication is warranted (5) In these patients, the prevention of
ischemia is paramount, therefore anticoagulation or antiplatelet
medication is warranted (5) Unruptured iVAD aneurysm should be
treated if they enlarge on follow-up or if the patient develops
recurrent symptoms on medical management (5) Unruptured iVAD
aneurysm should be treated if they enlarge on follow-up or if the
patient develops recurrent symptoms on medical management (5)
Slide 14
Unruptured iVAD 44 year old male presents with acute onset
slurred speech, nausea and headache. Non contrast CT shows expanded
and hyperdense left intradural vertebral artery and a small infarct
in the left cerebellum MRI comfirmed expanded vertebral artery
compatible with dissection. Acute cerebellar infarct was present on
diffusion. Both MRA and CTA showed the vertebral artery was
occluded. The patient was anticoagulated for 3 months and follow up
imaging showed that the vessel remained occluded
Slide 15
Management - Ruptured Ruptured iVAD are most commonly treated
with endovascular treatment (2) Ruptured iVAD are most commonly
treated with endovascular treatment (2) Early treatment is
important due to the risk of re-rupture thought to be approximately
(~50% @ 24hrs, ~80% @ 1wk (2,9,11) Early treatment is important due
to the risk of re-rupture thought to be approximately (~50% @
24hrs, ~80% @ 1wk (2,9,11) Therefore immediate treatment should be
performed secure the diseased segment Therefore immediate treatment
should be performed secure the diseased segment
Slide 16
Endovascular Treatment Options Trapping of diseased segment
usually coils Trapping of diseased segment usually coils
Reconstructive stent or flow diverter with or without coils
Reconstructive stent or flow diverter with or without coils
Slide 17
Coil trapping Endovascular historical standard Endovascular
historical standard Major advantage is immediate prevention of
re-bleed and technically straight forward Major advantage is
immediate prevention of re-bleed and technically straight forward
Most patients not suitable for test occlusion due to the acute
hemorrhage Most patients not suitable for test occlusion due to the
acute hemorrhage Unlike carotid blisters loss of access for
endovascular treatment of vasospasm is usually not a consideration
Unlike carotid blisters loss of access for endovascular treatment
of vasospasm is usually not a consideration Reported low rate of
morbidity even when involving PICA origin in small series. However
there is a known risk of severe ischemic complications due to
occlusion of brainstem perforators and spinal cord supply (7)
Reported low rate of morbidity even when involving PICA origin in
small series. However there is a known risk of severe ischemic
complications due to occlusion of brainstem perforators and spinal
cord supply (7)
Slide 18
Coil Trapping - Complication 50 year old male presents with
acute SAH, drowsy but otherwise intact. Angiography demonstrates
fusiform dissecting aneurysm of the intradural right vertebral
artery involving the origin of right PICA. The left vetebral artery
is co-dominant and anterior spinal artery supply is not seen The
aneurysm and dissected segment was coil occluded. The patient awoke
from anesthesia but would not breath or protect his airway. An MRI
performed showed a large right PICA territory infarct and also
extensive infarction of his cervical cord.
Slide 19
Reconstructive techniques Recent developments in stent
technology have enabled vessel preserving treatment of fusiform and
dissecting aneurysms Recent developments in stent technology have
enabled vessel preserving treatment of fusiform and dissecting
aneurysms Theoretical advantage is less risk of ischemic
complications Theoretical advantage is less risk of ischemic
complications Disadvantages are that antiplatelet medication is
required, often more technically demanding, securing the aneurysm
from re- bleed may not be achieved immediately i.e. higher risk of
early re-bleed than with coil trapping. Disadvantages are that
antiplatelet medication is required, often more technically
demanding, securing the aneurysm from re- bleed may not be achieved
immediately i.e. higher risk of early re-bleed than with coil
trapping. Anatomical considerations PICA involved (size of AICA),
anterior spinal origin, PICA origin and medullary perforators
Anatomical considerations PICA involved (size of AICA), anterior
spinal origin, PICA origin and medullary perforators Lots of
technical considerations: timing of antiplatelets, regular stent or
flow diverter, jail and coil or not Lots of technical
considerations: timing of antiplatelets, regular stent or flow
diverter, jail and coil or not
Slide 20
52 year old male prsents with neck pain and headache. CT shows
posterior fossa SAH. Neurologicaly intact. Angiography shows a
fusiform aneurysm of the intradural right vertebral artery beyond
PICA. The left vertebral artery had a severe origin stenosis and
was non-dominant.
Slide 21
Reconstructive Two overlapping flow diverting stents were
deployed and the aneurysm lumen coiled via a jailed microcatheter.
Complete occlusion of the aneurysm was achieved immediately with
preservation of the right PICA.
Slide 22
Summary iVAD are a rare but important cause of both SAH and
acute ischemia iVAD are a rare but important cause of both SAH and
acute ischemia Imaging diagnosis can be challenging and may require
more than one modality Imaging diagnosis can be challenging and may
require more than one modality For those presenting with ischemia
the primary focus should be prevention of further emboli For those
presenting with ischemia the primary focus should be prevention of
further emboli For those presenting with SAH the primary focus
should be treatment of the diseased segment (usually endovascular)
to prevent a re-bleed For those presenting with SAH the primary
focus should be treatment of the diseased segment (usually
endovascular) to prevent a re-bleed Coil trapping or stent assisted
vessel preserving techniques can be used Coil trapping or stent
assisted vessel preserving techniques can be used
Slide 23
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Slide 24
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