Sex-dependent characteristics and outcomes after clipping of unruptured intracranial aneurysms: a multicenter propensity score–matched study
Authors: Drexler Richard , Sauvigny Jennifer , Pantel Tobias F. , Ricklefs Franz L. , Catapano Joshua S. , Wanebo John E. , Lawton Michael T. , Sanchin Aminaa , Hecht Nils , Vajkoczy Peter , Raygor Kunal P. , Tonetti Daniel A. , Abla Adib , Naamani Kareem El , Tjoumakaris Stavropoula I. , Jabbour Pascal , Jankowitz Brian T. , Salem Mohamed M. , Burkhardt Jan-Karl , Wagner Arthur , Wostrack Maria , Gempt Jens , Meyer Bernhard , Gaub Michael , Mascitelli Justin R. , Dodier Philippe , Bavinzski Gerhard , Roessler Karl , Stroh Nico , Gmeiner Matthias , Gruber Andreas , Figueiredo Eberval G. , Samaia da Silva Coelho Antonio Carlos , Bervitskiy Anatoliy V. , Anisimov Egor D. , Rzaev Jamil A. , Krenzlin Harald , Keric Naureen , Ringel Florian , Park Dougho , Kim Mun-Chul , Marcati Eleonora , Cenzato Marco , Westphal Manfred , Sauvigny Thomas , Dührsen Lasse 
Published: June 2024

OBJECTIVE
Disparities in the epidemiology and growth rates of aneurysms between the sexes are known. However, little is known about sex-dependent outcomes after microsurgical clipping of unruptured intracranial aneurysms (UIAs). The aim of this study was to examine sex differences in characteristics and outcomes after microsurgical clipping of UIAs and to perform a propensity score–matched analysis using an international multicenter cohort.

METHODS
This retrospective cohort study involved the participation of 15 centers spanning four continents. It included adult patients who underwent clipping of UIAs between January 2016 and December 2020. Patients were stratified according to their sex and analyzed for differences in morbidities and aneurysm characteristics. Based on this stratification, female patients were matched to male patients in a 1:1 ratio with a caliper width of 0.1 using propensity score matching. Endpoints included postoperative complications, neurological performance, and aneurysm occlusion at discharge and 24 months after clip placement.

RESULTS
A total of 2245 patients with a mean age of 57.3 (range 20–87) years were included. Of these patients, 1675 (74.6%) were female. Female patients were significantly older (mean 57.6 vs 56.4 years, p = 0.03) but had fewer comorbidities. Aneurysms of the internal carotid artery (7.1% vs 4.2%), posterior communicating artery (6.9% vs 1.9%), and ophthalmic artery (6.0% vs 2.8%) were more commonly treated surgically in females, while clipping of aneurysms of the anterior communicating artery was more frequent in males (17.0% vs 25.3%; all p < 0.001). After propensity score matching, female patients were found to have had significantly fewer pulmonary complications (1.4% vs 4.2%, p = 0.01). However, general morbidity (24.5% vs 25.2%, p = 0.72) and mortality (0.5% vs 1.1%, p = 0.34), as well as neurological performance (p = 0.58), were comparable at discharge in both sexes. Lastly, rates of aneurysm occlusion at the time of discharge (95.5% vs 94.9%, p = 0.71) and 24 months after surgery (93.8% vs 96.1%, p = 0.22) did not significantly differ between male and female patients.

CONCLUSIONS
Despite overall differences between male and female patients in demographics, comorbidities, and treated aneurysm location, sex did not relevantly affect surgical performance or perioperative complication rates.