Postphlebitic syndrome is a condition of swelling and pain in the leg that has been affected by DVT. The postphlebitic syndrome can last for a very long time (more than a year) and can be very disabling. The causes of postphlebitic syndrome include persistent blockage of blood flow through the veins of the leg or damage to valves within the veins of the leg. If a blood clot (DVT) in a leg vein does not dissolve within the first few weeks after it forms, it frequently becomes scarred to the inside of the vein wall and causes a permanent blockage. Over a period of time, the leg will often gradually improve as alternate veins enlarge and create pathways for the blood to flow out of the leg. This takes time, however, and during the period of time that blood flow out of the leg is impeded by the blood clot, the leg swells, can become painful, and sometimes takes on a darker color due to the accumulation of blood in the extremity.

In some cases, the blood clot will dissolve within the veins as a result of treatment with blood thinners such as heparin, Lovenox, or Coumadin, but during the process of healing of the lining of the vein, the valves within the vein become damaged and no longer function properly. This allows blood to “reflux” meaning instead of pumping back up toward the heart, it accumulates in the leg and can cause swelling and pain. This “valvular insufficiency” is another cause of the postphlebitic syndrome. The treatment for this condition is to wear support stockings and wait for the passage of time and for the body to develop new vein pathways for blood to exit from the leg. Support stockings minimize the swelling and pain in the leg. Over the years, various vascular surgery operations have been attempted to try to correct the vein obstruction and to replace damaged valves within the veins, but they have been shown to be of minimal benefit and are rarely recommended for this condition.