Superficial vein thrombosis (SVT) of the lower limbs is associated with an increased risk of recurrent venous thromboembolism (VTE), but long-term risks beyond three years are largely unknown. The aim of our study was to identify the frequency of recurrent VTE in patients with lower limb SVT during a follow-up through five years following initial presentation.

Consecutive patients with SVT were treated with subcutaneous tinzaparin (Innohep™, LEOPharma, Denmark). Patients were stratified into three groups by the duration of treatment: group 1 ( ≤30 days ) and group 2 (31 - 60 days), which run in parallel and patients received mostly an intermediate or therapeutic dose and also a subsequent group 3 where patients received an intermediate dose ( 131iu/Kg ) for 90 days. The composite primary endpoint of this prospective cohort study was recurrent VTE, defined as occurrence of clinically evident SVT recurrence, deep-vein thrombosis or pulmonary embolism.

A total of 147 patients with a median age of 58.2 years were treated (group 1, n=60, group 2, n=38 and group 3, n=49).Four patients died, two were lost to follow-up and the remaining 141 patients were followed-up for five years. Recurrent VTE occurring in 27/147 patients (five-year rate 18.5%, Fig. 1), including 18 events of recurrent SVT, 7 events of deep-vein thrombosis and 2 events of pulmonary embolism. Fifteen events occurred early (during the first three months) and the remaining 12 late. Five-year recurrent VTE-free rates were significantly better with prolonged anticoagulation for the initial SVT event. These rates were 71.5% in group 1, 84.1%in group 2 and 91.7% in group 3 (Fig. 2, p for trend = 0.005).

Long-term recurrent VTE rates in patients presenting with SVT are not negligible, supporting the notion that SVT is not a benign disease. Anticoagulation for three months, a duration similar with VTE, may improve patient outcomes.