Prevention of delayed cerebral ischaemia

There is a compelling precedent for prophylaxis after SAH; up to 25% of patients with a ruptured aneurysm develop cerebral ischaemia between 5 to 14 days after the initial bleed.

The pathogenesis is complex and not fully understood. Narrowing of the arteries around the base of the brain is a necessary but insufficient factor.

Nimodipine is a calcium antagonist that reduces the influx of calcium in the smooth muscle cell through the blockage of the voltage-operated calcium channels

• may lead to reduced vascular smooth muscle constriction and a decrease in the release of vasoactive substances from endothelium and platelets
• has also been hypothesized that nimodipine may have direct neuroprotective properties
• many previous studies have proved the efficacy of prophylactic oral or intravenous nimodipine in reducing the evidence of cerebral infarction and improving outcomes after SAH

Nimodipine, in a dose of 60 mg orally every 4 hours or by nasogastric tube, reduced the incidence of cerebral ischaemia by one third (1)

Intra-arterial nimodipine is used in SAH to reduce risk of cerebral ischaemia (2,3).

Hypertension during the acute stage should generally be left untreated as it is probably a compensatory response to maintain cerebral perfusion.

Plasma volume must be maintained - at least 3 litres of fluid per day with iv fluids to supplement oral intake.

NICE note:

• consider enteral nimodipine for people with a confirmed subarachnoid haemorrhage
• only use intravenous nimodipine within a specialist setting and if enteral treatment is not suitable.

Reference:

• Van Gijn, 'Subarachnoid haemorrhage'. Lancet 1992; 339.
• Biondi A, Ricciardi GK, Puybasset L, et al. Intra-arterial nimodipine for the treatment of symptomatic cerebral vasospasm after aneurysmal subarachnoid hemorrhage: preliminary results. American Journal of Neuroradiology. 2004;25(6):1067-1076.
• Wolf S, Martin H, Landscheidt JF, Rodiek SO, Schürer L, Lumenta CB. Continuous selective intraarterial infusion of nimodipine for therapy of refractory cerebral vasospasm. Neurocritical Care. 2010;12(3):346-351
• NICE (November 2022).Subarachnoid haemorrhage caused by a ruptured aneurysm: diagnosis and management