What is the risk of rebleeding in spontaneous subarachnoid hemorrhage (SAH)?

From the Guidelines

The risk of rebleeding in spontaneous subarachnoid hemorrhage (SAH) is highest within the first 24 hours after the initial bleed, with rates of up to 15% in the first day, as indicated by recent evidence 1. This risk decreases over time but remains significant for several weeks. To prevent rebleeding, the primary intervention is early aneurysm securing, ideally within 24-72 hours of the initial hemorrhage, through either endovascular coiling or neurosurgical clipping, as supported by the 2023 guideline for the management of patients with aneurysmal subarachnoid hemorrhage 1. Some key points to consider in the management of SAH include:

• Early treatment of ruptured aneurysms reduces the risk of rebleeding and facilitates treatment of delayed cerebral ischemia (DCI) 1.
• The goal of initial treatment is complete obliteration of the aneurysm whenever feasible, as the risks of both rebleeding and retreatment are substantially higher in patients with incomplete obliteration of a ruptured aneurysm 1.
• Blood pressure control is also crucial, with systolic blood pressure typically maintained below 140-160 mmHg until the aneurysm is secured.
• Antifibrinolytic agents like tranexamic acid may be used for very short periods (less than 72 hours) in patients awaiting definitive treatment, but their long-term use is not recommended due to increased risk of ischemic complications. The high mortality associated with rebleeding underscores the importance of these preventive measures, as rebleeding causes sudden neurological deterioration through increased intracranial pressure and further brain damage. In terms of specific risk factors for rebleeding, previous studies have identified several patterns, including a higher risk with conservative therapy, with rates between 20% and 30% for the first month after hemorrhage, and then stabilizing at a rate of 3% per year 1. Recent evidence also suggests that poor neurological status, high Hunt-Hess grade, and larger aneurysm diameter are independent predictors of acute hydrocephalus, intraventricular blood, and the use of ventricular drains 1. Overall, the management of SAH requires a multidisciplinary approach, with early intervention and careful consideration of the risks and benefits of different treatment options.

From the Research

Risk of Rebleeding in Spontaneous Subarachnoid Haemorrhage

• The risk of rebleeding in spontaneous subarachnoid haemorrhage is a significant concern, as it can have a substantial impact on overall patient outcome 2.
• Rebleeding can occur in up to 4% of patients during the first day after initial aneurysmal bleed, although some studies suggest that this figure may be underestimated due to the failure to capture very early rebleeds 2.
• Ultra-early rebleeding, defined as bleeding within the first 24 hours following aneurysmal SAH, can occur in as many as 9-17% of patients, with most cases occurring within 6 hours of initial hemorrhage 2.
• Prompt aneurysm treatment is crucial to minimize the risk of rebleeding, with endovascular occlusion of the aneurysm with coils or surgical clipping being the primary treatment options 3, 4.
• The use of antifibrinolytic therapy to reduce rebleeding has been investigated, but studies have failed to clearly demonstrate overall therapeutic benefit, although short-course antifibrinolytic therapy may have a role prior to initial aneurysm repair 2.

Prevention and Management of Rebleeding

• Early surgical clipping of the aneurysm under the microscope is usually the initial treatment of choice to prevent rebleeding and allow for safe use of pressors in the event of clinical vasospasm 4.
• Endovascular coiling of the aneurysm has been shown to be associated with better short- and long-term outcomes than surgical clipping in select patients, although angiographic surveillance is necessary after endovascular treatment and retreatment with additional coiling may be required 3.
• Nimodipine, a calcium-channel blocker, is used to help prevent vasospasm-related ischemia, and transcranial Doppler sonography and cerebral angiography are used to assess the degree of vasospasm that develops in the first 2 weeks after aneurysmal rupture 4, 5.