In-stent Stenosis after p64 Flow Diverter Treatment

Abstract

PurposeThere is limited information available on the incidence of in-stent stenosis (ISS) secondary to the use of flow-diverting stents in the intracranial vasculature. We sought to determine the incidence, severity, and clinical course of ISS on angiographic follow-up after treatment of saccular aneurysms with p64.MethodsWe retrospectively reviewed all patients who underwent treatment of a saccular (ruptured and unruptured) intracranial aneurysm with ≥1 p64 between 2011 and 2015. Fusiform aneurysms and dissections were excluded. Aneurysms with prior or concomitant saccular treatment (e. g., coiling, clipping) were included. Extradural targets and aneurysms with parent vessel implants other than p64 were excluded. ISS was assessed on follow-up angiography and defined as <50% (mild), 50–75% (moderate), or >75% (severe).ResultsIn total, 205 patients (147 female, 71.7%; median age 57 years), with 223 saccular aneurysms were treated with p64 and had at least 9 months of digital subtraction angiography (DSA) follow-up completed. There was no DSA follow-up available in 8 patients. ISS of any degree at any time was recognized in 65/223 (29.1%) of all target aneurysms. The maximal degree of lumen loss was <50% in 40 lesions (17.9%), 50–75% in 19 lesions (8.5%), and >75% in 6 lesions (2.7%). ISS did not cause a focal neurological deficit in any patient. No progression from stenosis to occlusion was observed. Balloon angioplasty was performed in 1 lesion and was well tolerated. In 56 lesions (84.8%), a significant reduction of ISS occurred spontaneously, 2 mild stenoses remained stable, and for 6 lesions the long-term follow-up is pending.ConclusionTreatment with p64 is associated with an overall rate of 8.5% moderate ISS (50–75%) and 2.7% severe ISS (>75%), which is comparable with the rate of ISS reported in the literature for other flow diverting stents. There is a tendency for ISS to spontaneously improve over time.

Transient in-stent stenosis: a common finding after flow diverter implantation

“…Similar to our findings, partial improvement of ISS on long term FU has previously been described by John et al ,12 Aguilar Perez et al, 14 and Lubicz et al 1…”

“…Recently, Aguilar Pèrez et al 14 recognized ISS in 29% (65/223) of patients treated with p64. In the majority of cases (40/65), mild ISS was observed.…”

The occurrence of neointimal hyperplasia after flow-diverter implantation is associated with cardiovascular risks factors and the stent design

“…Surface treatment is essential for the optimum bioperformance of nitinol, and the nickel content in the oxide layer over the FDS will impact the levels of nickel ion release 20. Aguilar Pérez et al published a series of patients treated with the p64 FDS made from nitinol and platinum similarly to the SILK stent 21. They reported a 29.6% rate of NIH.…”

Delayed Stroke after Aneurysm Treatment with Flow Diverters in Small Cerebral Vessels: A Potentially Critical Complication Caused by Subacute Vasospasm

“…Although excellent occlusion rates of even challenging aneurysms accompanied by comparatively low procedural complication rates were reported, pathophysiologically yet obscure, delayed ischemic adverse events, despite sufficient platelet function inhibition, remain a concern [4,5,6]. In this regard, FDS-induced hemodynamic insufficiency with subsequent watershed ischemia, neointimal hyperplasia, in-stent stenosis, and secondary device deformations (fish-mouthing, peripheral tapering) were suspected as elicitors in some cases [7,8,9,10,11].…”