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Anticoagulant and antiplatelet therapy in patients with an unruptured intracranial aneurysm

Alejandro A Rabinstein, MD
Section Editors
Lawrence LK Leung, MD
Jose Biller, MD, FACP, FAAN, FAHA
Deputy Editor
Janet L Wilterdink, MD


Unruptured intracranial aneurysms are detected in up to 2 to 3 percent of older adults who undergo high-quality noninvasive intracranial arterial imaging (eg, magnetic resonance angiography, computed tomographic angiography). Subarachnoid hemorrhage from a ruptured intracranial aneurysm is associated with a short-term mortality of 40 percent, with one-half of survivors sustaining permanent neurologic injury. Thus, detection of an asymptomatic unruptured aneurysm creates a management dilemma in patients who have indications for antithrombotic therapy. (See "Unruptured intracranial aneurysms".)

This topic review will discuss issues related to anticoagulant and antiplatelet therapy in patients with an unruptured intracranial aneurysm.


Rates of rupture for previously detected unruptured aneurysms vary according to their size (ie, there is a greater risk of rupture in larger aneurysms), specific location (eg, higher rates of rupture with posterior circulation aneurysms) [1], as well as history of prior subarachnoid hemorrhage from a separate aneurysm [2]. This subject is reviewed in depth separately, and will only be reviewed briefly here (see "Unruptured intracranial aneurysms", section on 'Risk of aneurysm rupture'):

For patients with small (<7 mm) aneurysms in the anterior circulation and without a history of subarachnoid hemorrhage, the rupture rate is very low, below 0.1 percent per year.

For similar patients who have moderate-sized aneurysms (7 to 12 mm), the rupture rate averages 2.5 percent per year.

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Literature review current through: Nov 2017. | This topic last updated: Jul 23, 2014.
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