Introduction Aneurysmal subarachnoid hemorrhage (SAH) is a rare but devastating form of stroke. Endovascular therapy has been criticized for its higher rate of recanalization and retreatment. The safety and predictors of retreatment are unknown. We report the clinical outcomes, imaging outcomes and predictors for aneurysm retreatment after initial endovascular embolization.

Method We identified patients who underwent endovascular retreatment from July 2005 through November 2011. Aneurysm and patient data were collected. Periprocedural complications were reported as intraoperative perforation (IOP) or thromboembolic event (TEE). Aneurysm and patient characteristics were compared between aneurysms requiring retreatment and those not requiring retreatment to evaluate aneurysm retreatment predictors.

Results A total of 111/871 (13%) aneurysms underwent retreatment. Two (0.2%) were retreated for recurrent acute SAH, 82 (74%) aneurysms were located in the anterior circulation, 47 (42%) required stent and 5 (5%) required balloon assist during retreatment. There were a total of 5 (5%) IOP and 6 (5%) TEE from which 2 (2%) and 1 (1%) were symptomatic, respectively. Overall symptomatic events rate were 2.7%. Patients were followed up for an average of 15±14 months. Seven (0.8%) aneurysms required a second retreatment without any recurrent SAH. Multivariable analysis revealed an OR for aneurysms requiring retreatment of 2.965 for aneurysms presenting as aneurysmal SAH, 1.791 for aneurysms in the posterior circulation and 1.053 for aneurysms with large dome size.

Conclusions Aneurysm retreatment is a safe option without a significant increase in morbidity or mortality. SAH, posterior circulation aneurysms and larger aneurysm dome size are predictors of aneurysms requiring retreatment.