Experimental production of lesions in canine pulmonary arteries similar to those produced by Dirofilaria immitis infection.

Pulmonary arterial disease was produced by the placement of flexible polyvinyl chloride threads (similar in size, shape and flexibility to adult female Dirofilaria immitis) in the pulmonary arteries of dogs. Several different types of pathological change were apparent ranging from subendothelial oedema and endothelial loss, mild intimal proliferation and thrombus formation to organised fibrous encasement of the threads in areas where they had become impacted in the lumen of the artery. This range of pathological changes is very similar to that produced by D immitis and suggests that the intima of the canine pulmonary artery may react to different insults in a similar way.