title: Hemodynamic versus hydrodynamic effects of Guglielmi detachable coils on intra-aneurysmal pressure and flow at varying pulse rate and systemic pressure.
abstract: OBJECTIVE
  Alterations in intra-aneurysmal pressure and flow have been observed after treatment with Guglielmi detachable coils (GDCs). We wished to determine whether these changes could be assigned to a hydrodynamic effect of the coils themselves or a compound effect of coils plus thrombus formation.
  
  
  METHODS
  Intra-aneurysmal pressure and flow were measured with a 0.014-inch guidewire- mounted transducer in a canine aneurysm in vivo and in vitro before and after treatment with GDCs. Flow was evaluated by using the thermodilution technique. Pressure and flow were also recorded in a bifurcational silicone aneurysm mounted onto a flow phantom during variations in systemic pressure and pulse rate before and following the insertion of GDCs.
  
  
  RESULTS
  The insertion of GDCs induced a reduction in flow that was qualitatively similar when the aneurysm was perfused either by blood (in vivo) or with normal saline (in vitro). Quantitatively, however, flow was reduced less distinctly during perfusion with saline. In the silicone aneurysm, pressure was inversely related to pulse rate and increased with augmenting systemic pressure, whereas flow remained constant regardless of variations in pressure and pulse rate. After GDC placement, reduced flow was dependent on pulse rate but independent of systemic pressure.
  
  
  CONCLUSIONS
  GDCs significantly reduced flow even in the absence of thrombus, indicating that they have a purely hydrodynamic effect. In the silicone model, the decrease in intra-aneurysmal flow after coiling relied upon the pulse rate in a manner suggesting the presence of resonance phenomena.
authors.affiliation: Department of Radiology, University of Wisconsin Health Sciences Center, Madison, USA.
authors.forename: Angelika
authors.initials: A
authors.lastname: Sorteberg
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Sorteberg
authors.forename: Beverly D L
authors.initials: BD
authors.lastname: Aagaard
authors.forename: Alan
authors.initials: A
authors.lastname: Rappe
authors.forename: Charles M
authors.initials: CM
authors.lastname: Strother
mesh_terms: D000783:Aneurysm / Q000503:physiopathology*; D004867:Equipment Design; D006439:Hemodynamics; D008955:Models, Cardiovascular; D011312:Pressure; D011674:Pulse; D012039:Regional Blood Flow; D014656:Vascular Surgical Procedures / Q000295:instrumentation*; D014867:Water
chemical_list: D014867:Water