Cerebral Aneurysm Regrowth and Coil Unraveling After Incomplete Guglielmi Detachable Coil Embolization: Serial Angiographical and Histological Findings-Case Report-

Abstract

A 69-year-old woman suffered subarachnoid hemorrhage due to rupture of an aneurysm at the tip of the basilar artery. The aneurysm was treated by endovascular treatment using Guglielmi detachable coils but the aneurysm dome could not be completely packed. Serial angiography at 10 and 18 months after embolization showed progressive regrowth of the aneurysm with loosening and unraveling of the packed coils. The patient died accidentally after head injury and autopsy was performed. Examination of the aneurysm showed further regrowth and``relative coil compaction'' of the coil mass. Histological examination of the resected aneurysm showed no endothelialized membrane in the orifice and only minimal organized thrombus in the body of the aneurysm.

Are Coil Compaction and Aneurysmal Growth Two Distinct Etiologies Leading to Recurrence Following Endovascular Treatment of Intracranial Aneurysm?

“…Coil compaction is thought to be the most important contributing factor to aneurysm recurrence and it caused by the water hammer effect of the pulsatile flow and dissolution of the thrombus within the aneurysm; whereas the aneurysm recurrence may also occur due to the progressive degeneration of the elastin within the internal elastic lamina of aneurysm sac wall. “Coil unraveling” has also been reported by few case reports where the coil loops loosen the tight packing and actually increase in size leading to unsecured aneurysm . These processes might not be exclusive and most likely can occur simultaneously.…”

How Do Coil Configuration and Packing Density Influence Intra-Aneurysmal Hemodynamics?

“…This steady hemodynamic condition at the aneurysm wall combined with the previously mentioned low-shear stresses and low-velocity flow might be favorable hemodynamic conditions to isolate the aneurysm from the bloodstream. 9,28 In addition, it was observed how coil configuration reduces its influence on hemodynamics when packing density increases (Fig 5).…”

Long-term effects of antiplatelet drugs on aneurysm occlusion after endovascular treatment

“…The presence of flow in incompletely occluded or recanalized aneurysms prevents progressive thrombosis, thrombus organization and intra-aneurysmal scarring 11 33. Thus, the initial advantage of periprocedural anticoagulation (fewer thromboembolic events) may later become a disadvantage with regard to permanent aneurysm occlusion.…”