Presence of Residual Venous Thrombus at Warfarin Withdrawal: a Predictor for Recurrence after a First Episode of Symptomatic Provoked Proximal Deep Venous Thrombosis in Thai Population?

Objective: To assess the risk for venous thromboembolism (VTE) recurrence by presence of residual venous thrombus (RVT) at warfarin withdrawal following symptomatic first provoked proximal DVT.Methods: Medical records of 45 consecutive patients with symptomatic first provoked proximal DVTs who had undergone warfarin surveillance for ≥ 3 months were reviewed retrospectively. Altogether, 22 patients discontinued anticoagulation after ≥ 3 months regardless of duplex ultrasonography results of RVT diagnosed by compression ultrasonography. Another 23 patients discontinued anticoagulation after the RVT disappeared. Primary outcome was recurrent VTE.Results: Four of the 45 patients experienced recurrent VTE (8.89%), including 2 (9.00%) of 22 patients who had discontinued anticoagulant regardless of duplex ultrasonography results and 2 (8.70%) of 23 patients who discontinued anticoagulation after RVT disappearance (p = 0.963). All of the recurrent VTE were recurrent DVT.Conclusion: RVT at warfarin withdrawal was not a predictor for recurrence VTE following a first symptomatic provoked proximal DVT.