Pipeline Embolization for Intracranial Aneurysms

The occlusion rate of the aneurysm

The occlusion rate of the aneurysm at 6 months；O'Kelly Marotta classification: complete occlusion (D, entirely non-filling), near-complete occlusion (C, only entry remnant), and incomplete occlusion (A and B, subtotal and total filling).

in-stent stenosis

In-stent stenosis is defined as a growth process beyond the limits of stent mesh, which appears as a visible gap between the vessel lumen filled with contrast agent and stent struts. Stenosis ratio (SR) = \[1-(actual diameter of the most stenotic segment with digital subtraction/actual diameter of stent measured on without digital subtraction)\]\*100% When there was no appreciable gap, cases were described as patency. Intimal hyperplasia was labeled when the SR was less than 25 %. ISS was defined as an SR of ≥ 25 %, and the stenosis grade was classified as mild (25 % to 49 %), severe (50 % to 99 %), or lumen occlusion (SR = 100 %)

perioperative complications

perioperative complications；such as arterial perforation, iatrogenic arterial dissection, embolization in previously uninvolved vascular territory, arterial access site hematoma, and retroperitoneal hematoma. Arterial perforation will be defined at angiography by the operator and associated with subarachnoid hemorrhage. Iatrogenic arterial dissection will be defined at angiography by the operator. Arterial access site hematoma will be assessed as a complication of arterial access puncture and defined by clinical examination and anatomic imaging. Retroperitoneal hematoma will be assessed as a complication of groin puncture and defined by imaging (ultrasound or CT or MR angiography). The definition of embolization in previously uninvolved vascular territory is noted after recanalization of the primary occlusion site, any vessel occlusions distal from the primary occlusion site are considered emboli due to periprocedural thrombus fragmentation.