A composition containing a macrophage inhibitor may be administered in an effective amount to prevent, inhibit or reduce restenosis, thrombus or aneurysm formation in implanted polymeric vascular grafts. The composition may be administered prior to vascular graft implantation, at the same time as vascular graft implantation, following vascular graft implantation, or any combination thereof. Exemplary macrophage inhibitors include bisphosphonates, anti-folate drugs and antibodies, preferably in a controlled release or liposomal formulation.