The effect of wall mechanical properties on patency of arterial grafts

Normal arteries have properties which match the low output impedance of the heart to the high peripheral impedance. These properties can be assessed in terms of compliance (% diameter change per unit pressure change) as well as by other haemodynamic parameters. Experiments were designed using vein, Dacron and expanded polytetrafluoroethylene (PTFE) in a low flow canine femoral artery bypass model. No graft group achieved perfect patency. At twelve weeks 80% of vein grafts, 30% of Dacron grafts, and 15% of PTFE grafts remained patent. The compliance of vein grafts was maintained despite marked thickening of the wall. Patency was correlated at a highly significant level with compliance. The studies demonstrate that the matching of the mechanical properties of grafts to host arteries is important in the design of successful synthetic arterial grafts.