Assessment of the lymphatic system by indirect lymphography in patients with post-thrombotic syndrome

OBJECTIVE: Alterations in lower extremity lymph drainage caused by chronic venous obstruction (CVO) are not well studied, partially due to a lack of standardized imaging modalities to assess the quality of lymphatic drainage in the lower extremities of patients with postthrombotic syndrome (PTS). However, these changes are likely to have an impact on the severity of disease and clinical outcomes of intervention. In the current study, we investigated the feasibility and diagnostic value of pre-intervention indirect lymphography in patients with CVO along with their pre and post intervention Villalta scores.

METHODS: A total of 17 patients (21 limbs) with iliofemoral and caval CVO were included in the study between 2017 and 2018. The deep and superficial lymphatic vessels in both legs were assessed before venous recanalization and stenting. The quality of lymphatic flow was compared in legs with CVO and healthy legs. Moreover, the correlation between lymphatic changes and clinical severity of PTS was evaluated by the Villalta score and CEAP classification.

RESULTS: The mean patient age was 44 ± 12 years and 10 (59%) patients were female. Patients were treated a mean 25 ± 6 months after their first deep venous thrombosis (DVT). Five patients (29%) suffered from recurrent DVT. Mean pre-interventional Villalta score was 10.5 ± 1.46, post-interventional Villalta was 9.27 ± 1.12 (p:0.0096). Regarding the CEAP classification, 4 legs were in class 5, seven legs were in class 4, three legs were in class 3 and 2 respectively. The primary patency rate was 70.5% and secondary patency rate 82.5% after a mean 18-months of follow-up. Indirect lymphography of the superficial and deep lymphatic system was completed prior to intervention in both legs of all patients. According to qualitative criteria, abnormal lymphatic vessel function was found in 35.2% of the superficial and 58.8% of the deep lymphatic vessels of the affected legs. Further analysis in patients showed abnormal function of deep lymphatic vessels in all patients with moderate to severe PTS according to the Villalta score.

CONCLUSION: Indirect lymphography is a feasible diagnostic tool to evaluate the function of lymphatic vessels. Impaired drainage of the deep lymphatic system was found in all patients with moderate to severe PTS. The clinical meaning of these lymphatic changes is not clear, but an association with clinical severity and outcome is possible.