BIOMECHANICS OF GLUTARALDEHYDE-TREATED PORCINE AORTIC ROOTS AND VALVES - AN INVESTIGATION OF THE EFFECT OF PREDILATION OF THE ELASTIC AORTIC ROOT

The biomechanics and function of fresh porcine aortic roots and valves have been compared, with those of glutaraldehyde-treated roots prepar ed in a conventional manner without dilation of the elastic aortic roo t and with glutaraldehyde-treated roots prepared with permanent predil ation during fixation. The glutaraldehyde-treated aortic walls were si gnificantly less extensible than fresh walls, with a mean dilation of only 6% compared with 45% for the fresh root at 120 mm Hg pressure, Pe rmanent predilation of the aortic root during fixation allowed the tot al dilation of the fixed root to be increased to 19% at 120 mm Hg pres sure. The effective orifice area of the fresh root and valve was signi ficantly greater than those of the fixed roots and valves, with perman ent predilation fixation producing a significantly greater orifice are a than conventional fixation. The open-leaflet bending deformations we re found to be lower in the valves fixed after permanent predilation t han in the standard fixed valves. The glutaraldehyde-treated porcine r oot and valve does not reproduce the biomechanics and function of the fresh root, because of the reduced extensibility of the fixed aortic n ail. Permanent predilation during fixation helps to partially overcome the shortcomings of the fixed root, producing better function than a standard fixed valve.