Pipeline for unruptured aneurysms beyond the circle of Willis

Objective To investigate the efficacy and complications of Pipeline embolization device (PED) in the treatment of unruptured aneurysms beyond the circle of Willis. Methods A retrospective study was conducted on the clinical data of 14 patients with unruptured aneurysms beyond the circle of Willis treated with PED at Department of Interventional Neuroradiology, Beijing Tiantan Hospital , Capital Medical University (n=11) and Department of Neurosurgery, Beijing Tsinghua Changgung Hospital (n=3) from January 2016 to January 2019. Among those, 10 cases underwent PED implantation and 4 underwent PED-assisted coiling. Each case among the 14 patients had a single aneurysm. Eleven cases underwent first treatment and 3 were recurrent cases. Modified Ranking scale (mRS) was used to comprehensively evaluate the patients after surgery. Patients were followed up radiographically at 6, 12 and 24 months post surgery, and the O' kelly-Marotta (OKM) grading was used to evaluate aneurysm embolization. Results A total of 17 PEDs were implanted in 14 patients, all of which were successful. Immediate postoperative cerebral infarction was observed in 2 patients (1 case of ACoA dissecting aneurysm and 1 case of MCA M1 dissecting aneurysm), and the symptoms were improved after medication. One patient with MCA M1 dissecting aneurysm ruptured at 9 h post surgery and died after treatment. At discharge, there were 11 patients with good postoperative neurological function (mRS: 0-1) and 2 patientswith neurological dysfunction (mRS: 3). There were 12 patients who obtained follow-up post operation with an average follow-up duration of 3.0-6.0 (4.7±1.4) months. At last follow-up, the mRS scores were 0 in 11 cases and 1 in 1 case. Angiographic follow-up showed that 9 of the 12 aneurysms in the 12 patients were completely occluded and 3 had residual neck. All the 3 patients with recurrent aneurysms revealed complete embolization at 6-month follow-up post operation. Conclusions PED is generally safe and effective in the treatment of unruptured aneurysms beyond the circle of Willis which could have a good therapeutic effect on recurrent unruptured aneurysms beyond the circle of Willis. However, it might be associated with relatively high risk in treatment of MCA aneurysms. Key words: Intracranial aneurysm; Circle of Willis; Distal; Pipeline embolization device