Temporary Pulmonary Stent Placement as Emergency Treatment of Pulmonary Embolism: First Experimental Evaluation

Abstract

We aimed to evaluate the performance of a newly designed temporary stent device as a percutaneous emergency treatment of pulmonary embolism. 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. 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. 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. 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.