Dynamic internal compliance measurements of fresh and fixed artery

A new device is used to compare dynamic internal compliance of biologic vascular prostheses derived from bovine artery. These grafts were prepared using dialdehyde starch (DS), and a polyepoxy polyether compound (PC), as crosslinking agents. Internal compliance was measured using the Dynatek DCT1 Dynamic Compliance Tester, developed by Dynatek Laboratories. This device utilizes a variable speed DC motor coupled to miniature bellows, which displace a stroke volume controllable to within 0.5 microliter. The bellows displace fluid into and out of the graft, resulting in a sinusoidal change in internal pressure. Volumetric displacement is monitored by a linear voltage displacement transducer (LVDT) mounted on the motor coupling, whereas internal graft pressure is monitored by a miniature pressure transducer mounted on the closed end of the graft. For this series of experiments, a pressure range of 80-120 mmHg was used, with a cycle speed of 80 cycles/min. Preliminary results indicate that PC fixation of bovine artery results in a vascular graft with internal compliance somewhere between fresh tissue and DS fixation. This data confirms qualitative assessment. The DCT1 provides valuable comparative information on the dynamic internal compliance of vascular prostheses. These measurements reflect what occurs in the graft lumen, since they take into account wall compression and axial deformation. Further development is required to separate radial and longitudinal compliance components.