title: Temporary pulmonary stent placement as emergency treatment of pulmonary embolism: first experimental evaluation.
abstract: OBJECTIVE
  We aimed to evaluate the performance of a newly designed temporary stent device as a percutaneous emergency treatment of pulmonary embolism.
  
  
  BACKGROUND
  If thrombolysis is contraindicated or recanalization by thrombolysis delayed in patients with severe pulmonary embolism who are threatened by acute circulatory failure, percutaneous temporary pulmonary stent placement may represent an additional option before surgical embolectomy is considered.
  
  
  METHODS
  The newly designed temporary pulmonary stent is made from woven Nitinol and has a distal blunt end and a proximal crimped end, which is firmly fixed to a 0.035-inch guidewire. It is delivered through a 9.5-F polytetrafluoroethylene sheath using a pusher tube. Stent placement and removal were examined in 9 anesthetized sheep with experimentally induced pulmonary embolism. Hemodynamic parameters were recorded in 7 animals.
  
  
  RESULTS
  Delivery and removal of the stent was uneventful and rapidly accomplished. Stent placement was associated with a significant decrease in Miller angiographic index (from 11.2 +/- 3.1 to 3.8 +/- 1.9; p = 0.0001), heart rate (from 139 +/- 35 beats/min to 92 +/- 11 beats/min; p = 0.0129), and mean pulmonary artery pressure (from 32 +/- 14 mm Hg to 21 +/- 14 mm Hg; p = 0.0029) and a significant increase in mean aortic pressure (from 48 +/- 14 mm Hg to 61 +/- 8 mm Hg; p = 0.0080). Autopsy revealed neither wall damage nor parenchymal hemorrhage.
  
  
  CONCLUSIONS
  Our preliminary study proves the technical feasibility of temporary placement and removal of a newly designed dedicated pulmonary stent to recanalize centrally located embolic occlusions in severe pulmonary embolism. Animal experimental evaluation revealed rapid and significant circulatory improvement after stent placement.
authors.affiliation: Department of Applied Medical Engineering, Helmholtz Institute, Aachen, Germany. smiro@hia.rwth-aachen.de
authors.forename: Thomas
authors.initials: T
authors.lastname: Schmitz-Rode
authors.forename: Rajeev
authors.initials: R
authors.lastname: Verma
authors.forename: Joachim G
authors.initials: JG
authors.lastname: Pfeffer
authors.forename: Ralf-Dieter
authors.initials: RD
authors.lastname: Hilgers
authors.forename: Rolf W
authors.initials: RW
authors.lastname: Günther
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D011474:Prosthesis Design; D011655:Pulmonary Embolism / Q000628:therapy*; D012756:Sheep; D015607:Stents