Whether a blockage of the great vessels is serious or not depends mainly on whether the process of blockage is prolonged or not. If the blockage is sudden, it may lead to a sudden loss of blood supply to the limb, resulting in coldness, numbness, pain as well as a pale color of the skin, which, if it is not improved within six hours, will result in irreversible necrosis of the limb, with the consequence of amputation. However, if the blockage occurs for a longer period of time and is a slow progressing blockage, the opening of collateral vessels and the generation of neovascularization will lead to symptoms of insufficient arterial blood supply, such as intermittent claudication, but generally will not lead to serious necrosis of the limb.