title: Angular remodeling in single stent-assisted coiling displaces and attenuates the flow impingement zone at the neck of intracranial bifurcation aneurysms.
abstract: BACKGROUND
  Self-expanding intracranial stent-assisted coiling of bifurcation aneurysms has recently been shown to straighten target cerebral vessels, a phenomenon with unknown hemodynamic effect.
  
  
  OBJECTIVE
  To investigate the impact of angular remodeling in aneurysms treated with single stent-assisted coiling with the use of computational fluid dynamic techniques.
  
  
  METHODS
  Fourteen patients (7 women, mean age 55) who underwent stent coiling of 14 wide-necked bifurcation aneurysms were included based on the availability of high-resolution 3-dimensional rotational angiography. Pretreatment data sets underwent virtual aneurysm removal to isolate the effect of stenting. Wall shear stress and pressure profiles obtained from constant flow input computational fluid dynamic analysis were analyzed for apical hemodynamic changes.
  
  
  RESULTS
  Stenting increased the bifurcation angle with significant straightening immediately after treatment and at follow-up (107.3° vs. 144.9°, P < .001). The increased stented angle at follow-up led to decreased pressure drop at the bifurcation apex (12.2 vs. 9.9 Pa, P < .003) and migration of the flow impingement zone (FIZ) toward the contralateral nonstented daughter branch by a mean of 1.48 ± 0.2 mm. Stent-induced angular remodeling decreased FIZ width separating peak apical wall shear stress (3.4 vs. 2.5 mm, P < .004). Analysis of FIZ distance measured from the parent vessel centerline showed it to be linearly (r = .58, P < .002) and FIZ width inversely correlated (r = .46, P < .02) to vessel bifurcation angle.
  
  
  CONCLUSIONS
  Stent-induced angular remodeling significantly altered bifurcation apex hemodynamics in a favorable direction by blunting apical pressure and inducing the narrowing and migration of the FIZ, a novel response to intracranial stenting that should be added to intimal hyperplasia and flow diversion.
authors: Cerebrovascular and Endovascular Division, Department of Neurosurgery, Tufts Medical Center, Boston, Massachusetts 02111, USA.
authors: Bulang
authors: B
authors: Gao
authors: Merih I
authors: MI
authors: Baharoglu
authors: Adel M
authors: AM
authors: Malek
mesh_terms: D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity; D001807:Blood Vessel Prosthesis; D002536:Cerebral Arteries / Q000503:physiopathology* / Q000601:surgery*; D002560:Cerebrovascular Circulation; D003198:Computer Simulation; D057510:Endovascular Procedures / Q000295:instrumentation / Q000379:methods; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000503:physiopathology* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D015607:Stents; D016896:Treatment Outcome