Vein grafts are often used for bypassing the occluded arterial segments in diabetic people and those who are habituated to smoking. Thrombosis of the vein grafts occur in some patients though the veins look healthy from out side and it is often considered to be a technical problem and revision of the vein grafting is often done especially in peripheral vascular surgical patients. Hyperglycemia is known to effect the endothelial functions and endothelial derived relaxation is abnormal in the diabetic people to varying degrees depending on the exposure of the patient to the glycemic variability in the previous times. Now there seems to evidence to support that BMP-4 is probably responsible for this impaired EDR ( endothelium derived relaxations) which is not linked to cyclooxygenase-2 pathway.