Ruptured Intracranial Aneurysms: Factors Affecting the Rate and Outcome of Endovascular Treatment Complications in a Series of 782 Patients (CLARITY Study)

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In consideration of endovascular treatment of ruptured intracranial aneurysms, physicians must take into account the factors associated with higher rates of thromboembolic events (smoking, aneurysms >10 mm, and aneurysm neck >4 mm) and intraoperative rupture, especially in middle cerebral artery aneurysms.


To analyze the clinical and anatomic factors that affect the occurrence and outcome of complications (thromboembolic events and intraoperative rupture) in the endovascular treatment of ruptured intracranial aneurysms in a large multicenter series, the CLARITY study (Clinical and Anatomic Results in the Treatment of Ruptured Intracranial Aneurysms).

Materials and Methods

This study was approved by the institutional review boards of the participating centers, and written informed consent was obtained from all patients. In the CLARITY series, 782 patients (314 men, 468 women; age range, 19–80 years, mean age, 51.3 years ± 13.2 [standard deviation]) with 782 ruptured aneurysms underwent endovascular treatment for ruptured intracranial aneurysms at 20 institutions. Uni- and multivariate analyses were performed to determine factors (demographic characteristics, risk factors, anatomic factors, and therapeutic factors) that affect the occurrence of treatment-related complications.


A higher rate of thromboembolic events was observed in patients with aneurysms larger than 10 mm (28.0% vs 10.7% in patients with aneurysms ≤10 mm, P < .001), in smokers (16.1% vs 10.1% in nonsmokers, P = .015), and in patients with aneurysms with a neck larger than 4 mm (20.8% vs 11.0% in aneurysms with a neck ≤4 mm, P = .004).The frequency of intraoperative rupture was higher in patients with middle cerebral artery (MCA) aneurysms (8.5% vs 3.7% in patients without MCA aneurysms, P = .029), in patients younger than 65 years (5.0% vs 0.8% in patients older than 65 years, P = .032), and in patients without hypertension (5.4% vs 1.5% in patients with hypertension, P = .017).


The rate of thromboembolic events in the endovascular treatment of ruptured aneurysms is significantly affected by aneurysm size and neck size but not by aneurysm location. Conversely, the rate of intraoperative rupture is significantly affected by aneurysm location but not aneurysm size.

© RSNA, 2010

Supplemental material:


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Article History

Received December 5, 2009; revision requested February 3, 2010; revision received February 25; accepted March 18; final version accepted March 30.
Published online: Sept 2010
Published in print: Sept 2010