Comparative studies of prosthetic materials in the left atrium of the dog

To assess the healing process of various intracardiac prosthetic graft materials, we inserted autologous left atrium (control), autologous pericardium (AP), bovine pericardium (BP), polytetrafluoroethylene (PTEE) and woven Dacron (WD) patches into excised defects in the left atrial wall of 15 dogs. Two patches were implanted into each heart utilizing six patches for each material. Three months after graft placement, histological examination revealed chronic inflammation and fibrosis for all materials. Dense connective tissue surrounded the grafts in which fibrosis was most prominent. Cartilage formation occurred in 11 grafts: 5 BP, 4 PTFE, 1 control and 1 AP site. This change was not evident with WD. The extent of cartilage formation was greatest in BP. Bone formation occurred in 3 BP sites. 2 PTFE and 1 control site. Quantitative calcium concentrations were similar for all of the grafts without bone formation. Calcium concentrations at sites with bone formation averaged 15.13 mg/g +/- 6.39 mg/g compared to 0.939 +/- 0.419 for sites without bone formation (p less than 0.0001). We conclude that while inflammation, fibrosis and connective tissue thickening occur with healing of all graft materials, cartilage and bone formation differ with respect to the material employed.