Coil embolization for the treatment of peripheral veins:: A position statement of the International Union of Phlebology (UIP), the Australasian College of Phlebology (ACP), the Australia and New Zealand Society for Vascular Surgery (ANZSVS), the American Venous Forum (AVF), the American Vein and Lymphatic Society (AVLS), and the Interventional Radiology Society of Australia (IRSA)