Parent vessel occlusion after Pipeline embolization of cerebral aneurysms of the anterior circulation

Abstract

OBJECTIVE The Pipeline Embolization Device (PED) is now a well-established option for the treatment of giant or complex aneurysms, especially those arising from the anterior circulation. Considering the purpose of such treatment is to maintain patency of the parent vessel, postembolization occlusion of the parent artery can be regarded as an untoward outcome. Antiplatelet therapy in the posttreatment period is therefore required to minimize such events. Here, the authors present a series of patients with anterior circulation aneurysms treated with the PED who subsequently experienced parent vessel occlusion (PVO). METHODS The authors performed a retrospective review of all anterior circulation aneurysms consecutively treated at a single institution with the PED through 2014, identifying those with PVO on follow-up imaging. Aneurysm size and location, number of PEDs used, and follow-up digital subtraction angiography results were recorded. When available, pre- and postembolization platelet function testing results were also recorded. RESULTS Among 256 patients with anterior circulation aneurysms treated with the PED, the authors identified 8 who developed PVO after embolization. The mean aneurysm size in this cohort was 22.3 mm, and the number of PEDs used per case ranged from 2 to 10. Six patients were found to have asymptomatic PVO discovered incidentally on routine follow-up imaging between 6 months and 3 years postembolization, 3 of whom had documented "delayed" PVO with prior postembolization angiograms confirming aneurysm occlusion and a patent parent vessel at an earlier time. Two additional patients experienced symptomatic PVO, one of which was associated with early discontinuation of antiplatelet therapy. CONCLUSIONS In this large series of anterior circulation aneurysms, the authors report a low incidence of symptomatic PVO, complicating premature discontinuation of postembolization antiplatelet or anticoagulation therapy. Beyond the subacute period, asymptomatic PVO was more common, particularly among complex fusiform or very large-necked aneurysms, highlighting an important phenomenon with the use of PED for the treatment of anterior circulation aneurysms, and suggesting that extended periods of antiplatelet coverage may be required in select complex aneurysms.

Comparison of Pipeline Embolization Device Sizing Based on Conventional 2D Measurements and Virtual Simulation Using the Sim&Size Software: An Agreement Study

“…Even though the true consequences of this device-length reduction remain to be clarified in dedicated further research, it is intuitive that particularly for intradural aneurysms, the minimal amount of endoprosthetic material required to achieve a goal is desirable, as is the potential to remove uncertainties related to unexpected landing zones and, consequently, unpredictable wall apposition or unanticipated branch vessel coverage. [18][19][20][21] There were also cases in which virtual simulation suggested a longer device or where suggestion of a larger diameter led to an increase in length of the implanted PED (Fig 3). These, at times, very sizeable discrepancies between manually selected and computed optimal device dimensions typically occurred in large, dysplastic, or fusiform aneurysms of the extradural ICA, as well as in aneurysms associated with dissection (On-line Tables 1-3).…”

The Evolution of Flow-Diverting Stents for Cerebral Aneurysms; Historical Review, Modern Application, Complications, and Future Direction

“…Asymptomatic parent vessel occlusion is frequently associated with anterior circulation aneurysms 94) . In contrast, parent artery occlusion in the posterior circulation is often associated with significant morbidity and/or mortality 95) .…”

Placement of a Stent within a Flow Diverter Improves Aneurysm Occlusion Rates

“…Incomplete apposition is not only a handicap in the periprocedural period, it also leads to delayed stent occlusions in the coronary arteries 17 and after flow diversion, 18 which may occur as late as 3 years after device placement. [19][20][21] Improvement of apposition by stents may help maintain flow-diverter patency in the long term.…”