Aetiological, clinical and therapeutic prognostic factors for the evolution of deep vein thrombosis followed up with serial venous Doppler ultrasound.

Background: Deep vein thrombosis (DVT) is a dynamic process that can be followed up with Doppler ultrasound (DUS).

Aims: To evaluate the role of certain factors that can influence the evolution of DVT.

Methods: In 121 DVT patients (mean age 58.19 ± 14.47 years; 30 with no venous thromboembolism (VTE) identifiable risk factors (RF), 31 with weak RF, 30 with moderate RF and 30 with strong RF), DUS was performed at admission and after 1, 3, 6, 12 and 24 months. Favourable evolution was defined as complete resolution of thrombus, whereas unfavourable evolution was defined as incomplete resolution, thrombosis recurrence or post-thrombotic syndrome.

Results: Complete thrombus resolution was found at 1 month (M1) in 24.8% of patients, at 6 months (M6) in 49.6% and at 24 months (M24) in 61.2% of patients. Favourable evolution was seen in younger patients at M1 and M3 (P = 0.004 and P = 0.045) and in cases with earlier treatment (P < 0.0001). In proximal DVT, the risk of non-favourable evolution was higher (4.05 times at M3, 4.23 times at M6 and 4.29 times at M12). Patients with moderate RF had an earlier favourable evolution (40% at M1, 56.67% at M6 and 70% at M24), and patients with strong RF had the lowest rate of thrombus regression (20% at M1, 36.67% at M6 and 43.33% at M24).

Conclusions: DVT evolution can last up to 24 months. Older age, strong VTE RF, proximal DVT localisation and late start of therapy constitute unfavourable evolutive prognosis. These cases need closer clinical and DUS monitoring to prevent complications.