Low compliance and arterial graft occlusion

Early closure of arterial grafts is not fully understood. Patency loss in saphenous vein at 1 year is 12 to 30%. Synthetic grafts are worse. Stiff grafts may impede pulsatile flow and interfere with energy propagation. In vivo compliance (C, % radial change/mm Hg x 10(2) +/- SEM), derived from pressure and diameter measurements, was assessed in 38 arteries and 60 arterial grafts in a standardized canine femoral artery bypass model. Normal artery (C = 7.40 +/- 0.73) was more compliant than any graft (P < 0.01). At implantation, vein (C = 2.67 +/- 0.18) was more compliant than double velour Dacron (C = 1.86 +/- 0.16) or expanded polytetrafluoroethylene (C = 1.63 +/- 0.14) (P < 0.01). Vein graft patency at 2 weeks was 83%, Dacron 64% (P = 0.13), and PTFE 32% (P < 0.01). Vein compliance did not change with implantation. Vein patency was maintained, but Dacron fell to 29% and PTFE to 14% by 3 months. A definite correlation was shown between patency and compliance. It is suggested that more attention should be devoted to elastic properties in the design of arterial grafts.