What are the potential complications of coiling and stenting after subarachnoid hemorrhage (SAH) due to aneurysm rupture?

Complications of Coiling and Stenting After Subarachnoid Hemorrhage Due to Aneurysm Rupture

Stents or flow diverters should not be used for ruptured saccular aneurysms amenable to either primary coiling or clipping due to higher risk of complications. 1

Thromboembolic Complications

Thromboembolic events are among the most significant complications of endovascular treatment, particularly when stents are used:

• Stent-assisted coiling (SAC) carries a higher risk of thromboembolic complications compared to primary coiling alone
• Thromboembolic complication rates range from 6-15.4% with stent-assisted coiling in the acute setting 2, 3
• Risk factors for thromboembolic complications include:
  • Poor clinical grade (higher WFNS grade) 2
  • Larger dome-to-neck ratio 2
  • Inadequate antiplatelet therapy

Hemorrhagic Complications

Hemorrhagic complications are particularly concerning in the setting of SAH:

• External ventricular drain (EVD)-related hemorrhages occur in approximately 10% of patients with EVDs who undergo stent-assisted coiling 4
• Rebleeding risk is high in the acute phase before aneurysm treatment
• Antiplatelet therapy complications: Required for stent placement but increases hemorrhagic risk in the setting of SAH
• Symptomatic intracranial hemorrhage occurs in approximately 1.5-7.7% of patients undergoing stent-assisted coiling 3, 5

Procedural Complications

• Aneurysm rupture during procedure: Can occur during catheterization or coil deployment
• Coil migration or herniation: May lead to parent vessel occlusion
• Stent malposition or migration: May result in inadequate aneurysm neck coverage
• Technical failure: Reported in approximately 7% of stent-assisted coiling cases 4

Post-procedural Complications

• Delayed cerebral ischemia (DCI): Common complication after SAH requiring management with euvolemia and induced hypertension 1
• Hydrocephalus: Acute symptomatic hydrocephalus requires CSF diversion via EVD or lumbar drainage 1
• Vasospasm: May lead to ischemic complications
• Aneurysm recurrence: More common with coiling than clipping, requiring follow-up imaging 1

Treatment Selection Algorithm

1. Evaluate patient and aneurysm characteristics:

   • For posterior circulation aneurysms: Coiling is preferred over clipping 1
   • For anterior circulation aneurysms with good clinical grade: Primary coiling is recommended for 1-year outcomes 1
   • For patients <40 years: Clipping may be preferred for durability 1
   • For patients with large intraparenchymal hematoma: Emergency clot evacuation with clipping 1

2. When considering stent-assisted coiling:

   • Only use for wide-neck aneurysms not amenable to surgical clipping or primary coiling 1
   • For fusiform/blister aneurysms: Flow diverters are reasonable 1
   • Avoid stents/flow diverters for saccular aneurysms amenable to primary coiling or clipping 1

3. Antiplatelet management if stenting is necessary:

   • Multiple antiplatelet medications may reduce thromboembolic complications 6
   • Higher risk in patients with EVDs and poor clinical grade 5

Important Caveats

• Treatment decisions should be made by specialists with both endovascular and surgical expertise 1
• Complete obliteration of the aneurysm should always be the goal 1
• Low-volume hospitals (<10 aSAH cases per year) should consider transferring patients to high-volume centers (>35 aSAH cases per year) 1
• Immediate post-treatment cerebrovascular imaging is recommended to identify remnants requiring treatment 1

The decision between coiling and clipping must carefully balance the risks of the procedure with the goal of securing the aneurysm to prevent rebleeding, which is frequently fatal. The best outcomes are achieved when both endovascular and open surgical options are available and carefully considered for each individual patient.