International Journal of Artificial Organs vol:35 issue:8 pages:559-559
European Society of Artificial Organs edition:39 location:Rostock date:26-29 September 2012
External aortic root support is being evaluated as an alternative to total root replacement for Marfan syndrome. In this way cardiopulmonary bypass and Bentall operation can be prevented. The hypothesis that graft material becomes incorporated in the adventitia was tested in a comparative study in lambs.
MATERIAL AND METHODS
Graft material was wrapped around the carotid artery of six lambs. After a predefined 4-6 months implantation period the material was excised, histologically examined and stress tested.
We report on five lambs that grew from an average 16Kg to 27Kg, one animal died two weeks after implantation of pneumonia. Microscopy confirmed integrity of the vessel architecture within the sleeve. In one specimen there was mild oedema in the outer part of the media for less then 25% of the circumference. Other findings were consistent in all animals. Fibrosis was found for at least 50% of the adventitia. The lumen was normal but the vessel wall was significantly thickened. There was a significant increase in the maximum tensile strength of the supported segments (955 ± 372 N/cm2) compared to normal arterial tissue (188 ± 23 N/cm2).
Experimental limitations include the small numbers, necessary in a large animal experiment, but the findings were consistent and, we believe, representative of the biological response to external support. The external aortic root support mesh was well incorporated, the vessel wall was healthy, and its integrity preserved. Fibrosis of the tissue surrounding the adventitia and tensile force testing confirmed in this sheep model strengthening of the artery. There was no evidence of vessel wall thinning within the sleeve.