PRECLINICAL STUDY
Temporary Pulmonary Stent Placement as Emergency Treatment of Pulmonary Embolism
First Experimental Evaluation
Thomas Schmitz-Rode, MD*,*,
Rajeev Verma, MD ,
Joachim G. Pfeffer*,
Ralf-Dieter Hilgers, PhD and
Rolf W. Günther, MD
* Department of Applied Medical Engineering, Helmholtz Institute, Aachen, Germany
Department of Diagnostic Radiology, Aachen, Germany
Institute for Medical Statistics, RWTH Aachen University and University Hospital, Aachen, Germany.
Manuscript received December 14, 2005;
revised manuscript received April 6, 2006,
accepted April 18, 2006.
* Reprint requests and correspondence: Prof. Dr. Thomas Schmitz-Rode, Managing Director, Helmholtz Institute Aachen, Chairman, Department of Applied Medical Engineering, RWTH Aachen University and University Hospital, Aachen, Pauwelsstrasse 20, D-52074 Aachen, Germany. (Email: smiro{at}hia.rwth-aachen.de).
OBJECTIVES: 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.
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Abbreviations and Acronyms
| | AP = aortic pressure | | CVP = central venous pressure | | PAP = pulmonary artery pressure | | PCWP = pulmonary capillary wedge pressure | | PE = pulmonary embolism | | PTFE = polytetrafluoroethylene |
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