A patient with a ruptured 0.23 cm × 0.34 cm saccular aneurysm causing subarachnoid hemorrhage—should urgent endovascular coil embolization be performed now rather than observation?

Urgent Endovascular Coil Embolization is Indicated

This patient with a ruptured saccular aneurysm causing subarachnoid hemorrhage requires urgent endovascular coil embolization within 24 hours, not observation. The aneurysm should be secured immediately to prevent catastrophic rebleeding, which carries a 3-4% risk in the first 24 hours and increases to approximately 17% when systolic blood pressure exceeds 150 mmHg 1, 2.

Why Treatment Cannot Be Delayed

Early aneurysm securing (within 24 hours) reduces rebleeding risk and improves overall outcomes compared to delayed intervention 1, 2, 3. The evidence demonstrates that:

• Early treatment (<24 hours from ictus) results in lower death and dependency at 3 months compared with intermediate (4-7 days) or late surgery (≥8 days) 1
• Meta-analyses support the outcome benefit of treatment <24 hours versus >24 hours from hemorrhage onset 1
• The risk of rebleeding in untreated ruptured aneurysms is 20-30% in the first month, with the highest risk in the initial 24 hours 1, 2

Treatment Modality Selection

Endovascular coiling is the preferred treatment approach for this patient 1, 3. The 2023 American Heart Association/American Stroke Association guidelines recommend:

• For good-grade aneurysmal SAH with anterior circulation aneurysms amenable to both techniques, endovascular coiling is preferred over surgical clipping to achieve superior 1-year functional outcomes (Class I, Level A evidence) 1, 2, 3
• The Canadian Stroke Best Practice guidelines similarly state that for most patients with SAH who are technically eligible for endovascular or microsurgery treatment, an endovascular approach is preferred based on the ISAT trial 1

Aneurysm Size Considerations

The aneurysm dimensions (0.23 cm × 0.34 cm, or 2.3 mm × 3.4 mm) do not contraindicate treatment. While very small aneurysms (<3 mm) can be technically challenging for coil embolization 1, the fact that this aneurysm has already ruptured and caused SAH makes treatment mandatory regardless of size 1, 2.

Treatment Goals

The goal of initial treatment is complete obliteration whenever feasible 1, 2, 3. The evidence shows:

• Risks of both rebleeding and retreatment are substantially higher in patients with incomplete obliteration of a ruptured aneurysm 1
• If complete obliteration is not feasible during initial treatment, partial treatment aimed at securing the putative rupture site during the acute phase is reasonable to reduce early rebleeding risk, with planned retreatment within 1-3 months 1, 2, 3
• Complete occlusion after initial coil embolization occurs in approximately 54% of cases, with 88% achieving >90% occlusion 1

Critical Pre-Treatment Management

While preparing for urgent coiling, the following measures are essential:

• Maintain systolic blood pressure <160 mmHg using titratable agents (nicardipine, labetalol, or clevidipine) to prevent rebleeding while maintaining cerebral perfusion pressure 1, 2, 3
• Initiate nimodipine 60 mg orally every 4 hours for 21 days (if within 96 hours of SAH onset and adequate blood pressure) to improve neurological outcomes 1, 2, 3
• Transfer immediately to a high-volume center with neurocritical care services and both neuroendovascular and cerebrovascular surgeons available if not already at such a facility 1, 2, 3

Common Pitfalls to Avoid

Do not delay aneurysm securing based on aneurysm size alone 1, 2. The decision to treat is based on the fact that rupture has already occurred, not on size thresholds used for unruptured aneurysms 4.

Do not use stents or flow diverters for this ruptured saccular aneurysm if it is amenable to primary coiling, as these devices carry higher complication rates and require dual antiplatelet therapy (Class III – Harm recommendation) 1, 3, 5.

Do not administer routine antifibrinolytic therapy, as it does not improve overall outcomes despite reducing rebleeding risk 1, 2, 3.

Multidisciplinary Evaluation

Evaluation by specialists with expertise in both endovascular and surgical techniques is essential to optimally evaluate the relative risks and benefits of each treatment strategy 1, 3. However, given current evidence, endovascular coiling should be the primary approach unless specific anatomical features favor clipping 1.

Post-Treatment Follow-Up

Immediate post-treatment cerebrovascular imaging is mandatory after coil embolization to detect residual filling or incomplete occlusion that may require further intervention 2, 3. Delayed follow-up vascular imaging should be performed, with retreatment strongly considered if a clinically significant residual aneurysm is identified 1, 3.