Morphological alterations in dura mater encephali used as ventricular wall grafts in the canine heart.

: Structural changes within homologous dura mater patch-grafts surgically implanted in the right ventricular wall of the heart were studied in nine adult dogs utilizing light microscopy and transmission and scanning electron microscopy. Physical examination of the dogs after surgery presented no clinical signs of abnormalities caused by either the surgery or the nature of the graft. After one week of implantation, a fibrous organization extending from the wound margins over the entire graft greatly increased its thickness. In addition, it was observed that (1) an increase in cellularity, vascularity and connective tissue elements occurred on the external surface of the patch-graft, (2) these same changes occurred regardless of which surface (periosteal or arachnoidal) was used as the external or pericardial surface, (3) the graft core underwent a transition from a relatively acellular and avascular connective tissue structure into one that was heavily infiltrated by a variety of cellular elements and new blood vessels, and (4) these morphological changes were interpreted as an attempt to incorporate the graft into the host tissue, resulting in an increase in both viability and stability of the graft. These findings indicate that homologous dura mater is a suitable material for use in the surgical repair of the cardiac wall.