Blister aneurysms

1. Vipul Gupta
Neurointerventional Surgery
Artemis Agrim Institute of Neurosciences

2. Small Blister/dissecting…
 “Very small, friable, symptomatic”
 Blister aneurysms (BA) are rare lesions characterized by a
hemispherical shape and fragile walls
 Non-branching sites from the dorsomedial wall of the
internal carotid artery (ICA), anterior communicating
(AComA) and basilar artery …
 Small size & atypical location- RA & 3D needed
 Blister/disecting- rapid change in size and morphology in
follow-up angiograms
 Owaga A et al , Neurosurgery 2000;47:578
 Meling TR et al J Neurosurg 2008;108:662
 Sim SY et al J Neurosurg 2006;105:400

3. Management…
 Imperative to suspect the blister/dissecting aneurysm
planning surgical and endovascular procedures.
 Pathology - focal wall defects covered by a thin layer of
fibrous tissue and adventitia and lack of usual collagenous
layer
 High risk of premature rupture during surgery, large
lacerations
 Endovascular- difficult to coil, friable, continued growth,
stent needed (issues in SAH)
 Shikawa T, Neurosurgery 1997;40:403
 Lee BH et al J Neurosurg 2008

4. Blister aneurysms …
 Classical ICA blister aneurysms
 Dissecting aneurysm with a bleb
 Very small berry aneurysms

5. Issue- blister;
control- protamine,
coils

6. Evolution of endovascular mgt…
 Weak nature of BA and small size of the aneurysms with a
broad neck renders endovascular treatment technically
challenging
 A stent placement is essential in most cases so as to retain
the coils within the aneurysm sac.
 Attempt to pack the aneurysm with coils may result in intra-
operative rupture and loose packing is likely to result in
continued growth of aneurysm
 Overlapping stents- may be preferable
 Aneurysm recurrence/growth can happen- early follow-up,
further treatment
Small Blister/dissecting…

7. Stents
 Flow modification
 Intimal growth and healing
 Change of angles
Issues
Persistent filling
Anti-platelet therapy in SAH
Single/double/flow divertor

8. Stent….
 Flow diversion
 Intimal growth- healing
 Angle of the artery

9. Stent …

11. Classical blister aneurysm
34-year M, SAH

12. 2 overlapping stents
1-year follow-up

13. Single stent
3-month follow-up
43-year M, SAH

15. Follow up after 6 months

17. Recurrence , PVO

18. Our experience…
NO. OF PATIENTS
MALE
FEMALE
14
9
5
MEAN AGE 49.7 YEARS
PRESENTATION
SAH
ISCHEMIC STROKE
13
1
NO OF STENTS
ONE STENT
TWO OVERLAPPING STENTS
11
3
LOCATION
ACA
PARACLINOIDAL
SUPRACLINOIDAL
ICA BIFURCATION
VERTEBRAL ARTERY-PICA
BASILAR ARTERY
PCA
2
7
1
1
1
1
1
COMPLICATION
THROMBOEMBOLISM, dissection
BLEEDING (extracranial – 1)
4, 1
Repeat SAH- None
FOLLOW UP- ANGIOGRAM
COMPLETE OCCLUSION
ALMOST COMPLETE
PATIAL OCCLUSION
NO OCCLUSION-UNCHANGED
NOT AVAILABLE
5 (3-month- 2-year)
3 (3-6 months)
3 (3-6 month)
2 (3-month F/U)
1 (< 3-month)

19. Surgical Options…..
 Direct clipping, clipping plus wrapping, wrapping alone,
clipping with Sundt encircling graft clips, encircling silicone
clip application, primary suturing of ICA, vascular staple clip
closure of ICA and trapping with or without extracranial-
intracranial bypass
 Exposure of cervical ICA for proximal control before
aneurysm dissection, gentle subpial dissection, complete
trapping of the aneurysm before clipping and good brain
protection, STA preparation
 As far as possible trapping of the aneurysm should be
avoided in acute phase of subarachnoid hemorrhage
(oblique clipping)
Small Blister/dissecting…

20. Further evolution –
flow diverters (stents)

21. 0
1
2
3
4
5
6
7
8
9
10
0 10 20 30 40 50 60 70 80 90 100
Flow
index
Ineffectiv
e
(clotting) Ineffect
ive
(free
flow
)
Effective flow
diversion and
side
branch
patency

22. DSA – Blister aneurysm of left ICA
Antiplatelet protocol:
Ecosprin 150 mg
Prasugrel 50 mg
2 hrs prior to stent deployment
Heparin 3000 IU at start of procedure
1000 IU to 2000 IU prior to stent deployment
ACT 300 (x 2 upper limit of normal)
A 63-year-old female patient presented with Fisher
grade 2 subarachnoid hemorrhage.

23. D E F
B CA B

24. B
C D
A

26. U. Sarkar

27. 21/12/15
24/12/15

29. Pasugrel seems to be safe and effective
Timing: 2 hours (maximal antiplatelet activity
starts at 2 hours)
Low risk of thromboembolism
Our series – 11 patients
- No thromboembolism or bleeding
-None needed EVD
-mRS – 0, 1 – 10/11
-Not suitable in patients with history of ischemic stroke and
age > 75
Key learning points

30. 17 patients: SS, ODS, SS+Coil
1 rebleed (died)
Good outcome on f/u – 82%
Mortality – 18%
Blister Aneurysm

31. Our experience with FD vs non FD
Complete occlusion – 89% vs 71% i.f.o FD
Repeat treatment – none vs 11.7% i.f.o FD
Rebleed resulting in death – none vs 5.8% i.f.o FD
Submitted for publication

32. Learning points
• FD was safe and effective in these aneurysms and
compared favorably with our previously reported results
with stent(single/overlapping) and coiling
• In our series loading with Pasugrel and ecospirin was
safe and effective for flow diverter placement in acutely
ruptured blister aneurysms
• Timing is critical, we loaded two hours before the
procedure

33. Blister aneurysms …
 Blister aneurysm on other arteries
 Many may be dissecting in nature
 Role of FD may not be so well established

34. Dissecting blister
aneurysm – poor grade
EVD
2-overlapping Enterprise stents

35. 6-months follow-up
Had repeated nasal & gastric bleedings
(Varices, Cirrhosis) - Anti-platelets were
reduced
Almost completer recovery except partial
vision loss due to vitreous hemorrhages

39. 54-year F, SAH
Single stent
1-year follow-up

40. 34-year M, TIAs (Ischemia with aneurysm)

42. A B C
D E F

45. Very small berry
aneurysms

47. 53 year man
SAH H&H grade 2

48. Small blister/dissecting
 Small blister/dissecting- important to detect and recognize
 Difficult cases for surgery or endovascular
 Previous Options- single stent, overlapping stents, stent and
coil
 Current TOC in ICA – FD
 Careful anti-platelet protocol
 Distinguish between blister vs dissecting vs very small berry

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