A prospective 10-year study of the post-thrombotic syndrome in a surgical population.

A total of 564 patients undergoing laparotomy entered a prospective 10-year study to determine the influence of postoperative DVT relative to other thrombotic episodes on the subsequent development of post-thrombotic syndrome (PTS). Pre-existing venous thrombotic disease and postoperative thromboses were assessed at the initial hospitalisation. Subsequent thrombotic episodes and signs of PTS have been monitored at biennial review. Thirty-five patients had PTS by the tenth year but it was already present in 16 before the index operation. Twenty-six patients without previous thrombotic episodes developed spontaneous DVT or phlebitis during the 10-year follow-up. New leg ulcers developed in six patients. Although all thrombotic episodes, irrespective of the relation to the index operation, increased the risk of PTS, most PTS occurred in patients without recognised DVT, although most had lesser venous problems prior to operation. PTS should be seen as resulting from the summation of a number of incidents of damage to the leg veins rather than one postoperative incident. Direction of prophylactic effort to patients with pre-existing venous problems may best reduce PTS among patients undergoing abdominal surgery, but will not make a major impact on the total population incidence of PTS.