• Venous anomalies are an under-recognized cause of deep venous thrombosis (DVT). Our study had anomalies in 2.8% of proximal lower limb DVTs.

  • In females under 50 years, 14% had venous anomalies, thus further workup should be considered in at-risk groups as it can affect management.

Anatomical variants, such as May-Thurner syndrome (MTS) and inferior vena cava (IVC) variants, are under-recognized causes of deep venous thrombosis (DVT), despite affecting management. We aimed to identify the proportion of anatomical variants in proximal lower limb DVT. A retrospective cohort study was performed with cases of acute proximal DVT from 2014-2021 identified from ICD-10 codes. We identified 4731 DVTs and included 1268 proximal DVTs. Thirty-six (2.84%) had an anatomical variant (25 MTS, 11 IVC variants), with a rate of 14.39% in females under 50 years. Compared to non-variant DVTs, they were more likely to be unprovoked (81% vs 23%), younger (median age 37 vs 63 years), female (67% vs 37%), and have post-thrombotic syndrome (22% vs 9%). Variants frequently received thrombolysis (58% vs 1%) or angioplasty (47% vs 0%), and indefinite anticoagulation (83% vs 40%). Further investigation for variants should be considered in high-risk patients as it impacts management.

This content is only available as a PDF.

Article PDF first page preview

Article PDF first page preview

Supplemental data