THE CLINICAL COURSE OF DEEP-VEIN THROMBOSIS - PROSPECTIVE LONG-TERM FOLLOW-UP OF 528 SYMPTOMATIC PATIENTS

Background and Objective. In contrast to the extensive documentation o n the short-term outcome of patients with acute deep vein thrombosis ( DVT) of the lower extremities, little is known about the long-term cli nical course of this disease. To determine the clinical course of pati ents with a first episode of symptomatic DVTn over an 8-year follow-up period. The primary aims were to assess the long-term incidence of re current venous thromboembolism and that of the post-thrombotic syndrom e. In addition, we determined mortality and evaluated potential risk f actors for all these outcomes. Methods. This was designed as a prospec tive cohort follow-up study. Consecutive symptomatic outpatients with a first episode of venography proven DVT were treated with an initial course of full-dose (low molecular weight) heparin, followed by at lea st three months of oral anticoagulants. After discharge, they were ins tructed to wear compression elastic stockings for at least two years. Follow-up assessments were scheduled at three and six months, and then every six months up to eight years. Diagnosis of recurrent venous thr omboembolism was made according to standard criteria. The presence of post-thrombotic syndrome was evaluated using a standardized scale. Res ults. A total of 528 consecutive patients with a first episode of veno graphy confirmed DVT were included in the study. The cumulative incide nce of recurrent venous thromboembolism after two, five and eight year s was 17.2, 24.3 and 29.7%, respectively. Malignancy and impaired coag ulation inhibition increased the risk of recurrent venous thromboembol ism (RR=1.48 and 2.0, respectively). In contrast, surgery and recent t rauma or fracture were associated with a diminished risk of recurrent venous thromboembolism (RR=0.65 and 0.39, respectively). The cumulativ e incidence of post-thrombotic syndrome after two, five and eight year s was 24.5, 29.6 and 29.8%, respectively. The development of ipsilater al recurrent DVT was strongly associated with the risk for post-thromb otic syndrome (risk ratio, 2.4). Survival after eight years was 69%. T he presence of malignancy increased the risk of death remarkably (risk ratio, 7.1). Interpretation and Conclusions. Symptomatic DVT carries a high risk for recurrent venous thromboembolism that persists for man y years, especially in patients without transient risk factors for DVT . The post-thrombotic syndrome occurs in almost one-third of patients and is strongly related to recurrent ipsilateral DVT. Our findings cha llenge the widely adopted short course of anticoagulation in patients with symptomatic DVT. (C) 1997, Ferrata Storti Foundation.