Timing of Treatment in Aneurysmal Subarachoid Haemorrhage – Does Every Hour Count?

Introduction: Pre-intervention rebleeding following aneurysmal subarachnoid haemorrhage (ASAH) is a devastating complication with high associated morbidity and mortality. Early aneurysm treatment is advocated in guidelines for management of ASAH to minimise this risk though there is debate regarding the exact optimal timeframe of aneurysm treatment. In this study, we examine the hour-by-hour effect of earlier treatment.

Methods: We performed a prospective observational study examining the relationship between timing of aneurysm treatment and functional outcome in ASAH. The primary outcome was a poor functional outcome at 3 months defined by a Glasgow Outcome Score (GOS) of 1-3. Logistic regression models examining the outcome in relation to time to aneurysm securement were fitted, adjusted for World Federation of Neurosurgical Societies (WFNS) score at presentation. Patients not selected for aneurysm treatment due to poor prognosis and patients with Fisher Grade 1 ASAH were excluded.

Results: We identified 1,550 patients with SAH, of whom 873 were eligible for inclusion in the present study. Overall, the risk of a poor outcome increased consistently at a rate of 0.2% per hour to treatment (95%CI 0-0.4), such that the risk was 4.2% higher (95%CI 0.7-7.7) at 24 hours compared with immediate treatment, 8% higher (95%CI 0.9-17.1) at 48 hours and 14.4% (95%CI 0.7-28.2) at 72 hours. This effect was larger in poor grade patients (WFNS grade 4-5), who had a 7.1% increased risk at 24 hours (95%CI 0.8-13.5). In patients with Fisher Grade 4 ASAH, the risk was 6.4% (95%CI 2-10.9) at 24 hours compared with 1.4% (95%CI 0.1-2.8) in Fisher Grade 3 and 2.4% (95%CI 0.3-4.4) in Fisher Grade 2.

Conclusion : Our study demonstrates a small but cumulative benefit of earlier aneurysm securement. These findings suggest that aneurysm treatment should be pursued as early as possible where safe and feasible within clinical and logistical context.