Compliance, elastic modulus, and burst pressure of small-intestine submucosa (SIS), small-diameter vascular grafts

Small-intestine submucosa (SIS) is cell-free collagen, 100 mu Chick, derive d from the small intestine. It has been used as a vascular graft and has th e highly desirable property of remodeling itself to become host tissue. To date there has been limited reportage on its preimplantation mechanical pro perties as a vascular graft. In this study, compliance, elastic modulus, an d burst pressure have been measured on 5- and 8-mm SIS grafts. The complian ce (percent of diameter increase for a pressure rise from 80 to 120 mmHg) w as 4.6% av (range 2.9 to 8.6%) for the 5-mm grafts. For the 8-mm graft, the increase in diameter for the same pressure rise was 8.7% av (range 7.2 to 9.5%). The modulus of elasticity (E) increased exponentially with increasin g pressure according to E = E(o)e(alpha P); where E-o is the zero-pressure modulus and alpha is the exponent that describes the rate of increase in E with pressure; the units for E, E-o, and P are g/cm(2). The mean value for E-o was 4106 (g/cm(2) range 1348-5601). The mean value for alpha was 0.0059 (range 0.0028-0.0125). At 100 mmHg, the mean value for E was 8.91 x 10(3) g/cm(2) (range 1.02-8.80 x 10(3)). The mean burst pressure for 5.5-mm graft s was 3517 mm Hg (range 2069-4654). in terms of preimplant compliance, the small-diameter SIS graft is about 1/2 as compliant as the dog carotid arter y, about four times more compliant than a typical vein graft, and more than an order of magnitude more compliant than synthetic vascular grafts. (C) 1 999 John Wiley & Sons, Inc.