To evaluate the feasibility of the pulmonary artery stenting through the animal experimental study of stenting success rate and biocompatibility.

Eight adult mongrel dogs were randomly divided into two groups (each four). Cook Zliver 635 self-expanding stents have been placed into the pulmonary artery in their right lower lungs using interventional techniques under general anesthesia. Experimental group 1 took anticoagulants in a period spanning from 2 days before the operation to 12 weeks after it, while experimental group 2 took anticoagulants in a period spanning from 2 days before operation to 6 weeks after it. All the animals underwent DSA examination before and immediately after operation, after 6 weeks and 12 weeks; 6 weeks and 12 weeks after operation, they underwent CT pulmonary angiography; pulmonary artery pressure, tidal volume and blood gas analysis were checked 6 weeks and 12 weeks before and after operation. The animals were sacrificed 12 weeks after operation, and specimens were taken. Stenting procedure, postoperative imaging, histopathology specimens were evaluated through statistics on technical success rate, frame endothelial coverage rate, tidal volume, stenosis rate after stenting, blood gas analysis and other parameters. Data were analyzed with paired t test and the Friedman test using SPSS 13.0 software package.

Pulmonary vascular stents were successfully placed in the right lungs of all the eight animals. Stenting was smoothly operated, with a successful stent expansion and a well-satisfied position. Postoperative imaging of the 8 animals showed no stent stenosis, displacement, deformation, fracture or other changes, but the CT pulmonary angiography showed 2 cases of proximal stent not fully attached to the vessel wall. Inspection on pulmonary artery pressure, tidal volume and blood gas analysis found no significant change. Four cases of stent were completely endothelialized, but another 8 not all of them were distal endothelialization, instead of proximal; 1 was about 30% endothelialized, 2 about 50%, and the other 1 about 70%. Endothelialization was more easily found at the distal end than at the proximal end. Endothelization was not clearly distinguished between those 2 groups. The branch vessels covered by the stent were not clogged. Endothelium grew round blood vessel branches.

Self-expanding stents could be successfully placed in the pulmonary artery of dogs, which has no significant effect on respiratory function or right ventricular function. Pulmonary vascular stenting is safe and feasible.