Early Thrombus Removal versus Best Medical Therapy in Acute Iliofemoral Deep Vein Thrombosis: A Summary of the Literature from the Last Decade

Introduction, Objectives, and/or Purpose: Post-thrombotic syndrome (PTS) is a serious consequence of acute iliofemoral deep vein thrombosis (DVT) resulting from venous hypertension and/or residual venous obstruction. Anticoagulation is a mainstay of treatment, but as many as 50% of patients will still develop PTS within 2-years of DVT. Novel endovenous therapies have been developed to remove thrombus in the acute setting. This systematic review and meta-analysis summarises the evidence for early thrombus removal since the publication of the first randomised controlled trial just over a decade ago, to analyse the evidence supporting this treatment and current areas of deficiency.

Methods: The review followed PRISMA guidelines using a registered protocol (CRD42022328766). The MEDLINE and Embase databases, the Cochrane library, ClinicalTrials.gov, European Union Clinical Trials and the International Standard Randomised Controlled Trial Number registry were searched without restrictions up to 15th May 2022. Randomised controlled trials of early thrombus removal, reporting the rate of PTS in patients with acute iliofemoral DVT were included. The primary outcomes were the rate of PTS, moderate-severe PTS and major bleeding. Due to the presence of statistical heterogeneity, studies were pooled with a random-effects meta-analysis.

Results: Four studies were included in the head-to-head meta-analysis, all of which utilised pharmacomechanical thrombectomy systems as the early thrombus removal strategy. The risk of PTS after early thrombus removal and BMT versus BMT alone was 0.68 (95% CI 0.45-1.02) (4 studies, 867 participants). Heterogeneity as reported by the I2 statistic was 76%. The risk of major bleeding in the early thrombus removal and BMT group was 5.08 (95% CI 1.11-23.32). Other adverse events reported by studies included minor bleeding, ecchymosis, and haematuria.

Conclusion(s): Meta-analysis of the four randomised controlled trials of early thrombus removal in addition to BMT for the acute iliofemoral DVT cohort demonstrates a trend towards lower rates of PTS in the intervention group, albeit with significant heterogeneity. This may be explained by the use of concurrent procedures like endovenous stenting, the definitions of PTS used in each of the trials of the definitions of primary venous patency that differed between each trial. Furthermore, the risk of major bleeding with early thrombus removal and BMT is five times higher than BMT. Future trials of novel technologies such as purely mechanical thrombectomy, are needed to protect patients from undue bleeding risk.