Michael Lanfranchi MD, Presenter: Nothing to Disclose

Robert Heller BS, Abstract Co-Author: Nothing to Disclose

Neel Madan MD, Abstract Co-Author: Consultant, Near Infrared Imaging, LLC

Daniel Calnan MD, Abstract Co-Author: Nothing to Disclose

Adel M. Malek MD, PhD, Abstract Co-Author: Research support, Johnson & Johnson Research support, Boston Scientific Corporation

Incomplete stent apposition (ISA) of the closed-cell design Enterprise stent following intracranial aneurysm-stent coiling has been associated with increased risk of delayed thromboembolic events. Our purpose was to investigate the natural history of incomplete stent apposition and its clinical consequences.

All patients receiving Enterprise stents in the treatment of intracranial aneurysms since January 2009 have undergone serial 3-Telsa magnetic resonance (MR) imaging. ISA is identified by the Crescent sign on multi-planar reconstructions of MR angiography. MRI/MRA imaging obtained at 3, 9, and 18 months post stent-coiling were analyzed for infarction. Admission and follow-up medical records were also evaluated for clinically evident ischemic events.

50 patients receiving Enterprise stents were included in the study. ISA was identified on post-operative imaging of 22/50 (44%) patients, with 19/22 (86%) Crescent signs persisting, and 3/22 (14%) Crescent signs resolving on subsequent serial imaging. Delayed ischemic events occurred in 8/50 (16%) cases, all of which harbored ISA. The events were transient ischemic attacks (TIAs) in 5 cases, asymptomatic radiologic strokes in 2 cases, and symptomatic strokes and TIAs in the final case. There were no delayed events in patients without ISA. Only one event (2%) was permanent and symptomatic. Post-operative and persistent Crescent sign was significantly associated with delayed ischemic events (P<.001 and P=.0015, respectively).

Incomplete stent apposition is a temporally persistent phenomenon, which spontaneously resolves in only a small minority of cases and appears to be a risk factor for delayed ischemic events. Although further investigation is needed, these results suggest that a recommendation of longer anti-platelet maintenance may be warranted in cases of recognized ISA .

The higher rate of delayed thromboembolic events associated with ISA suggests the need for continued clinical surveillance and maintenance of anti-platelet therapy.

Lanfranchi, M, Heller, R, Madan, N, Calnan, D, Malek, A, Incomplete Stent Apposition in Enterprise Aneurysm Stent-Coiling Is Persistent and Represents a Risk for Delayed Thromboembolism.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12034623.html