Interventions in the Treatment of Cerebral Aneurysms What

Interventions in the Treatment of Cerebral Aneurysms

What is brain Aneurysm? � A brain aneurysm, also referred to as a cerebral aneurysm or intracranial aneurysm (IA), is a weak bulging spot on the wall of a brain artery very much like a thin balloon or weak spot on an inner tube. � Over time, the blood flow within the artery pounds against the thinned portion of the wall and aneurysms form silently from wear and tear on the arteries. As the artery wall becomes gradually thinner from the dilation, the blood flow causes the weakened wall to swell outward. � This pressure may cause the aneurysm to rupture and allow blood to escape into the space around the brain. A ruptured brain aneurysm commonly requires advanced surgical treatment

catheter arteriography

brain arteries

anterior circulation

posterior circulation

subarachnoid space ventricles

CT scan of a subarachnoid hemorrhage (SAH)

a SAH is (almost) always due to the rupture of a cerebral aneurysm : because these arterial dilatation of the cerebral arteries are usually to be found in the subarachnoid space

Treatment options for Brain Aneurysms: �Surgical clipping �Endovascular coiling �Parent artery sacrifice with or with out bypass surgery. �Conservative management (no treatment)

clip open surgery

where is the aneurysm? SAH

where is the aneurysm?

surgical clip

before after

clips

Endovascular treatment for Brain aneurysms: Coiling of aneurysm Stent assisted coiling Balloon assisted coiling Flow diverters

coils endovascular treatment

SAH rupture of an aneurysm at the tip of the basilar artery

before after

unruptured aneurysms is it possible to recognize those that will rupture?

Coiling of aneurysm: Endovascular (meaning within the blood vessel) embolization, or coiling, uses the natural access to the brain through the bloodstream via arteries to diagnosis and treat brain aneurysms. The goal of the treatment is to safely seal off the aneurysm and stop further blood from entering into the aneurysm and increasing the risk of rupture or possibly rebleeding. Following diagrams show aneurysm coiling is done Coil mass inside aneurysm prevents blood from entering it

Balloon assisted coiling: In slightly wide necked aneurysms balloon assistance is taken to coil an aneurysm in order to prevent prolapse of coil mass into the artery.

Stent assisted coiling: For wide necked aneurysms stent can be placed to hold coil mass inside the aneurysm.

Other techniques of stent assisted coiling in wide necked aneurysms Using double stents in Y shape to coil complex wide necked aneurysms

Flow diverter is a kind of stent which can be used with out use of coils.

Safety and Effectiveness � Coil embolization is safe in the short-term. Complications associated with coil embolization ranged from 8. 6% to 18. 6% with a median of about 10. 6%. � Observational studies showed that coil embolization is associated with lower complication rates than surgical clipping (permanent complication 3 -7% versus 10. 9%; overall 23% versus 46% respectively, p=0. 009). � Common complications of coil embolization are thrombo-embolic events (2. 5%– 14. 5%), perforation of aneurysm (2. 3%– 4. 7%), parent artery obstruction (2%– 3%), collapsed coils (8%), coil malposition (14. 6%), and coil migration (0. 5%– 3%)

Results Ruptured Aneurysms � Randomized controlled trials showed that for ruptured intracranial aneurysms with SAH, suitable for both coil embolization and surgical clipping (mostly saccular aneurysms <10 mm in diameter located in the anterior circulation): Coil embolization resulted in a statistically significant 26% relative risk reduction in the composite rate of death and disability (modified Rankin score 3– 6) at 1 -year. � There was no significant difference in mortality rates (8%– 13. 5% for coil embolization and 10%– 15. 8% for surgical clipping). ¾ Coil embolization is associated with less frequent MRI-detected superficial brain deficits and ischemic lesions at 1 -year. � The 1 -year rebleeding rate was 2. 2% after coil embolization and 1% for surgical clipping. The statistical significance is unclear. � Observational studies showed that patients with SAH and good clinical grade had better 6 -month outcomes and lower risk of symptomatic cerebral vasospasm after coil embolization compared to surgical clipping

Unruptured Aneurysms � There were no randomized controlled trials that compared coil embolization to surgical clipping. Large observational studies showed that: The risk of rupture in unruptured aneurysms less than 10 mm in diameter is about 0. 05% per year for patients with no pervious history of SAH from another aneurysm. � The risk of rupture increases with history of SAH and as the diameter of the aneurysm reaches 10 mm or more. � Coil embolization reduced the composite rate of in hospital deaths and discharge to longterm or short-term care facilities compared to surgical clipping (Odds Ratio 2. 2, 95% CI 1. 6– 3. 1, p<0. 001). � The improvement in discharge disposition was highest in people older than 65 years. � In-hospital mortality rate following treatment of intracranial aneurysm ranged from 0. 5% to 1. 7% for coil embolization and from 2. 1% to 3. 5% for surgical clipping. � The overall 1 -year mortality rate was 3. 1% for coil embolization and 2. 3% for surgical clipping. One-year morbidity rate was 6. 4% for coil embolization and 9. 8% for surgical clipping. It is not clear whether these differences were statistically significant. � Coil embolization is associated with shorter hospital stay compared to surgical clipping.

Angiographic Efficiency and Recurrences � The main drawback of coil embolization is its low angiographic efficiency. The percentage of complete aneurysm occlusion after coil embolization (27%– 79%, median 55%) remains lower than that achieved with surgical clipping (86%– 100%). � However, about 90% of coiled aneurysms achieve near total occlusion or better. Incompletely coiled aneurysms have been shown to have higher aneurysm recurrence rates, these being 7% to 39% for coil embolization compared to 2. 9% for surgical clipping. � Recurrence is defined as refilling or the neck, sac, or dome of a successfully treated aneurysm as shown on an angiogram. The long-term clinical significance of incomplete occlusion following coil embolization is unknown, but in one case series, 20% of patients had major recurrences and 50% of these required further treatment.

Long-Term Outcomes �There is a lack of long-term studies on coil embolization. Accordingly, there is uncertainty about the long-term outcomes of this procedure, such as long-term occlusion status, coil durability, recurrence rates, and rebleeding rates. �While surgical clipping is associated with higher immediate procedural risks, its long-term effectiveness has been established.

Indications and Contraindications �Coil embolization offers treatment for people at increased risk for craniotomy, such as those over 65 years of age, with poor clinical status, or with comorbid conditions. The technology also makes it possible to treat surgical high-risk aneurysms.

Suitable Aneurysms � Not all aneurysms are suitable for coil embolization. Suitability depends on the size, anatomy, and location of the aneurysm. Aneurysms more than 10 mm in diameter or with an aneurysm neck greater than or equal to 4 mm are less likely to achieve total occlusion. They are also more prone to aneurysm recurrences and to complications such as coil compaction or parent vessel occlusion. � Aneurysms with a dome to neck ratio of less than 1 have been shown to have lower obliteration rates and poorer outcome following coil embolization. � Furthermore, aneurysms in the middle cerebral artery bifurcation are less Coil Embolization suitable for coil embolization. � For some aneurysms, treatment may require the use of both coil embolization and surgical clipping or adjunctive technologies, such as stents and balloons, to obtain optimal results.

Which one of the two modalities is better? Coiling or Clipping? Morbidity and Mortality: ISAT TRIAL (for ruptured aneurysms): Dead or dependent at one year- � � Surgical group: 30. 6% patients were dead or dependent at one year Endovascular group: 23. 7% of patients were dead or dependent at one year ISUIA trial (for unruptured aneurysms) Death and dependency at 1 year: � � Surgical group: The 1 -year morbidity and mortality rate was 12. 2%, and the mortality rate was 2. 3%. Endovascular treatment: The 1 -year total morbidity and mortality rates were 9. 5% and 3. 1%, respectively.

Economic Analysis �Economic studies showed that treatment of unruptured intracranial aneurysm smaller than 10 mm in diameter in people with no previous history of SAH, either by coil embolization or surgical clipping, would not be effective or costeffective. �If the percentage of all aneurysms treated by coil increases from 10% to 40%, the budget impact is estimated at $3 to $3. 5 million per year for the province.

Conclusion 1 � At 1 year, coil embolization is safe and yields better functional outcomes for patients with subarachnoid hemorrhage from an acute ruptured aneurysm that is equally suitable for endovascular or surgical therapy. � Level 4 evidence suggests that coil embolization of unruptured aneurysms may be associated with comparable or less mortality and morbidity, shorter hospital stay, and less need for discharge to short term rehabilitation facilities. The greatest benefit was observed in people over 65 years of age. � At present, surgical clipping still appears to be the gold standard for treating intracranial aneurysms in eligible patients because of its established long-term effectiveness. The decision to choose surgical clipping or coil embolization needs to be made jointly by the neurosurgeon and neuro-intervention specialist, based on the assessment of the risk of rupture against the risk of the procedure, as well as the morphology of the aneurysm.

Conclusion 2 Coil embolization offers treatment for people for whom treatment is necessary but surgical clipping is too risky or not feasible. It should be considered under the following circumstances: v Patients in poor/unstable clinical or neurological state v Patients at high risk for surgical repair (e. g. people>age 65 or with comorbidity) v Aneurysm(s) with poor accessibility or visibility for surgical treatment due to their location (e. g. ophthalmic or basilar tip aneurysms)

Conclusion 3 � Coil embolization may also be used in place of surgical clipping for other intracranial aneurysms predicated on the morphology of the aneurysm, and at the discretion of the neurosurgeon and the neurointervention specialist. � The extent of aneurysm obliteration after coil embolization remains lower than that achieved with surgical clipping. Aneurysm recurrences after successful coiling may require repeat treatment with endovascular or surgical procedures. � Caution that long-term outcomes of coil embolization are unknown at this time. � Long-term follow-up after coil embolization is important. � The performance of endovascular coil embolization should take place in centres with expertise in both neurosurgery and endovascular neuro-interventions, with adequate treatment volumes to maintain good outcomes. Distribution of the technology should also take into account that patients with SAH should be treated as soon as possible with minimal disruption if possible.

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