Temporary surgical clipping of flow-diverted arteries in an experimental aneurysm model

Abstract

obJeCtive Surgical management of recurrent aneurysms following failed flow diversion may pose difficulties in securing vascular control with temporary clips. The authors tested the efficacy and impact of different types of aneurysm clips on flow-diverted arteries. Methods Six wide-necked experimental aneurysms were created in canines and treated with Pipeline flow diverters. In 4 aneurysms, occlusion of the artery at the level of the proximal and distal landing zones (n = 2 per aneurysm) was attempted, using temporary, fenestrated, single, and double permanent aneurysm clips. Two aneurysms served as unclipped controls. Serial angiography was performed to investigate the efficacy of clip occlusion, flow diverter deformation, and thrombus formation. After the animals were killed, the flow-diverted aneurysm constructs were opened and photographed to determine neointimal or device damage as a result of clip placement. results Angiography-confirmed clip occlusion was only possible for 4 of 8 of the tested flow-diverted arterial segments. Clip application attempts led to filling defects consistent with thrombus formation in 2 of 4 flow-diverted constructs, and to minor damage of the flow diverter with neointimal fracture in 1 of 4 cases. CoNClusioNs Aneurysm clips placed on canine parent arteries bearing a Pipeline flow diverter were unable to reliably stop blood flow. Application of aneurysm clips can cause mild damage to the device and neointima, which might translate into thromboembolic risks. If possible, vascular control should be sought beyond the terminal ends of the implanted device.

Optimal use of temporary clip application during aneurysm surgery – In search of the holy grail

“…In an animal study, Darsaut et al showed repeated clip slippages, inadequate occlusions, damage to the device, and increased risk of thrombo-embolic strokes after clip occlusion of "Pipeline flow" diverted vessels. [33] In an in vivo study on synthetic vessels made of silicon, three self-expanding stents, Neuroform by Boston Scientific, Enterprise stent by Codman, and Pipeline flow diverting stent by Medtronic, were studied. After temporary clip application, Neuroform and Enterprise stents, both made of Nickel-Titanium alloy (Nitinol), showed immediate flow arrest and return to original shape on clip removal.…”

Re-treatment of residual aneurysms after flow diversion: An experimental study

“…5 Other re-treatment options may include parent vessel occlusion, with or without surgical creation of a bypass, or other surgical management of the residual. 6,7 Aneurysm re-treatment after failure of flow diversion has never been studied in an animal model.…”