The influence of smoking and plasma factors on prosthetic graft patency.

The effects of smoking and plasma risk factors on the patency of prosthetic femoro-popliteal bypass grafts were investigated in 93 patients entered into a multicentre trial of prosthetic graft materials (70 patients had patent grafts and 23 patients had occluded grafts 2 years after surgery). The smoking markers thiocyanate and fibrinogen were significantly higher in patients with occluded grafts, whereas LDL-cholesterol was significantly higher in patients with patent grafts 2 years after bypass. Based on smoking markers, graft patency in smokers was 57% at 2 years by life table, compared to 78% in non-smokers. P less than 0.05. Fibrinogen was an important variable, predicting graft occlusion with graft patency in patients with below median fibrinogen levels, being 84% at 2 years by life table compared to 51% in those with above median fibrinogen levels, P less than 0.025. Although increased levels of LDL-cholesterol have been associated with accelerated atherosclerosis, patients with above median levels of LDL-cholesterol had improved graft patency (83%) at 2 years compared to patency in patients with below median LDL-cholesterol (60%), P less than 0.05. The plasma risk factors associated with the failure of prosthetic grafts are similar to those associated with the failure of saphenous vein grafts, indicating that higher fibrinogen levels and smoking may contribute to an hypercoagulable state. Greater efforts are needed to stop patients smoking after vascular reconstruction.