Ch76 SAH from cerebral aneurysm rupture Flashcards
(23 cards)
What vessel wall changes are seen with aneurysms?
Less elastin and thin muscle in the tunica media
What should be considered if a patient has a peripheral / distal aneurysm?
Mycotic aneurysm
Where do fusiform aneurysms tend to occur?
Vertebrobasilar system
What is the most common aneurysm location?
ACom 30% PCom 25% MCA 20% Basiar 10% Vertebral 5% *30% of patients has multiple aneurysms
Through which structure do ACom aneurysms rupture through to cause IVH?
The lamina terminalis
What visual field defect is normally seen with opthalmic artery aneurysms?
Nasal quadrantanopia
What visual field defect is normally seen with Acom aneurysms?
Chiasmal syndrome (bitemporal hemianopia + optic atrophy)
Why do intracavernous aneurysms cause facial pain>
Compression of V1 or V2 in the cavernous sinus
Which conditions are associated with aneurysms?
Mnemonic - PF ME HEMAN Polycystic kidney disease Fibromuscular dysplasia Marfan’s Ehler’s Danlos type 4 HHT Endocarditis MEN type 1 AVMs NF1
What % of patients with AD polycystic kidney disease develop intracerebral haemorrhages?
15% - mostly MCA. There is a 10 fold increase in SAH with these patients compared to the general population. Screening with MRA every 5 years may be beneficial.
What is Hunterian ligation?
Ligation of the ICA or CCA for giant aneurysms. Usually needs bypass to prevent strokes.
Which studies compare Clipping vs Coiling?
ISAT BRAT Finnish study Chinese study
Summarise ISAT methodology
>2000 patients enrolled (from 10,000 eligible) Between 1997-2002 - mostly europe, canada and australia Stopped prematurely as there was a 7% absolute risk reduction with coiling (31% vs 24%) at 1 year of poor outcome
What are the criticisms of ISAT?
Only 20% of eligible patients were enrolled - selection bias Expertise of surgeons vs interventionalists not reported 90% of aneurysms were <1 cm and 97% were anterior circulation. Probability of independent survival at 5 years was no different between groups.
Summarise the BRAT trial
North American version of ISAT. Intention to treat - had high cross over from coil to clip. Difference 34% vs 20% poor outcome with clipping at one year but no difference at 3 years except posterior circulation aneuryms were better at all time time points with coiling.
What are the results of the meta-analysis of clip vs coil trials?
Lanzino et al 2013 pooled data from Finnish/ISAT/BRAT at one year and showed that poor outcome at one year was less with coiled patients but mortality was unchanged. Rebleeding rates within the first month were higher with coiling.
Which aneurysms favour clipping?
Treatment decisions should be MDT: MCA Wide neck Associated haematoma requiring evacuation Mass effect of aneurysm causing CN3 palsy Younger age
What is the advantage of early aneurysm occlusion?
Removes early rebleed risk Facilitates treatment of complications e.g. vasospasm Overall mortality is reduced Allows clot removal decompressing the brain
What is the risk of bleeding from a neck remnant after clipping?
4% over 10 years - occurs when the clip is no perpendicular across the neck leaving a dog ear
How do you reduce the CMR02?
Barbiturates e.g. thiopentone titrated to isoelectric EEG. Also helps to redirect blood flow to ischaemic cortex.
What is the maximum time for temporary clipping?
5 minutes
When can aneurysm rupture occur during surgery?
Initial exposure - due to increased transmural pressure when opening the dura Aneurysm dissection - tearing with blunt dissection Clip application - inadequate exposure causing clip to penetrate aneurysm
What is the rate of recurrence after clipping?
1% @ 5 years
