Accuracy of contralateral Villalta score to assess for pre-existing chronic venous insufficiency in patients with unilateral deep vein thrombosis.

Background: International guidelines recommend using the Villalta score (VS) to diagnose the postthrombotic syndrome (PTS). However, a high proportion of PTS detected with VS could just reflect the presence of preexisting primary venous insufficiency (PVI). Furthermore, it is unclear whether the contralateral VS (cl-VS) can be used to assess for preexisting PVI.

Objectives: To estimate whether cl-VS can be used to assess for preexisting PVI, and to assess the proportion of PTS that could be attributable to preexisting PVI.

Methods: Subanalysis of the SOX multicenter randomized trial focusing on patients with a first unilateral proximal deep vein thrombosis (DVT) followed for up to 2 years. PVI was defined as a baseline cl-VS > 4, and PTS as VS > 4 in the leg ipsilateral to DVT starting 6 months after DVT.

Results: Among 680 patients, mean cl-VS remained stable over time: 1.23 (standard deviation [SD] ±2.49) at baseline and 1.17 (±2.20), 1.59 (±2.81), 1.54 (±2.50), 1.65 (±2.82), and 1.55 (±2.63) at the 1-, 6-, 12-, 18-, and 24-month visits, respectively. Baseline cl-VS and ipsilateral VS measured during follow-up were mildly correlated (Pearson correlation = 0.13-0.25). This association disappeared after subtracting the cl-VS measured at the same visit from the ipsilateral VS. Overall, 48.8% of patients developed PTS of whom 12.8% had baseline cl-VS > 4.

Conclusion: In our study of patients with a first unilateral proximal DVT, the proportion of patients with PTS who had a cl-VS > 4 is modest. However, cl-VS appears to be stable over time. Its assessment could constitute a simple way of documenting preexisting PVI and help to classify patients as having PTS.