Preventable poor outcome from rebleeding by emergency aneurysm occlusion in patients with aneurysmal subarachnoid haemorrhage.

INTRODUCTION: The risk of rebleeding is highest during the initial hours after aneurysmal subarachnoid haemorrhage (aSAH), but the aneurysm is not occluded in all patients immediately after admission.Our aim was to determine the proportion of aSAH patients with poor outcome from early in-hospital rebleeding that can be prevented by three emergency aneurysm occlusion regimes. PATIENTS AND METHODS: From our prospectively collected database, we retrieved from all aSAH patients admitted between July 2007 and July 2017 data on clinical condition on admission, time of rebleeding, and outcome at 3 months. RESULTS: Of 1391 consecutive aSAH patients, 923 were in good clinical condition and had an aneurysm on initial imaging that was amenable for treatment. Poor outcome from rebleeding could have been avoided by treatment <4 h during day time shifts in 4 (0.4% [95% CI: 0.2-1.1]) patients (number needed to treat [NNT]: 250), by treatment and <1 h during daytime shift in 9 (1.0% [95% CI: 0.5-1.8]; NNT: 111), and treatment <1 h at 24/7 basis in 16 (1.7% [95% CI: 1.1-2.8%]; NNT: 59). DISCUSSION: Emergency aneurysm occlusion can reduce poor outcome due to rebleeding, but only in small proportions of patients. Whether such strategies lead to improved outcome for all patients and are cost-effective is highly uncertain. CONCLUSION: We do not recommend instalment of a treatment regimen where occlusion of ruptured aneurysm is performed within 1 h on a 24/7 basis.