Characterization of Venous Graft Wall Motion as an Indicator of Distal Anastomosis Quality in Coronary Artery By-Pass Surgery

An essential parameter in assessing anastomosis quality and graft patency is associated with the graft flow rate measured at the end of a by-pass surgery. To date, no objective method to determine the quality of the anastomosis graft and to obtain graft flow rate has been endorsed by the medical community. This paper describes a non-invasive technique for measuring the integrity of a venal graft in a coronary artery bypass upon conclusion of surgery. An in vitro laboratory setup was designed to illustrate the dynamic conditions in a coronary by-pass graft. Experiments were conducted for a graft with constant flow and for a graft with pulsatile flow. The behavior of the vein wall was examined when both ends of the graft were open to flow, and also when one end of the graft was occluded. The dynamic behavior of the graft was found to change as a function of graft patency and venal pressure. A correlation was confirmed between the oscillation frequency at the graft mid span and the change in pressure at vein exit.