Long-term consequences of deep vein thrombosis.

Following an overt episode of deep vein thrombosis (DVT), the long-term prognosis of the patient is predominantly obscured by three natural complications: recurrence of venous thromboembolism (VTE), post-thrombotic syndrome and death. Antithrombotic treatments have been proven effective in preventing recurrence of VTE but carry the risk of major bleeding. A high mortality rate persists during the first year following an acute VTE, with a small but continuing risk beyond the first year. Recurrences of VTE account for the minority of causes of deaths. With effective initial anticoagulant treatment, the early (within approximately 3 months) risk of recurrence is 3-6%. Long-term follow-up studies have shown that although the risk of recurrence of VTE beyond the first 6 months is lower, the risk persists over several years. Approximately 25% of DVT patients remain asymptomatic in the long term but severe signs of post-thrombotic syndrome (ulceration) are observed in 2-10% of patients 10 years after DVT. Major advances have been made in the management of acute VTE but the excess risks of death, recurrence of VTE and post-thrombotic syndrome persist for several years following the initial event. Appropriate therapeutic strategies for these events are still being developed and future study should be directed towards finding the optimal regimen for patients who require prolonged treatment.