May‐Thurner syndrome prevalence as a risk factor for acute deep vein thrombosis is unknown

Abstract

An excellent review on MayThurner syndrome prevalence has recently been published and described the challenge to establish a correlation between significant left common iliac vein compression and clinical outcomes.1 The authors mention the condition is responsible for 2% to 5% of all deep vein thromboses (DVTs).1 However, we want to point out that MayThurner syndrome (iliac vein compression syndrome or iliocaval compression syndrome) prevalence as a responsible risk factor for all DVTs is most likely unknown. The references cited in the article refer to two unicentric cohort studies led by the same author in which 18/900 (2%) patients and 40/800 (5%) patients presenting with presumed lower extremities’ venous disorders had features compatible with iliocaval compression.2,3 Not every patient was assessed by venography and detailed demographics and other risk factors for DVT were not provided. Moreover, diagnosis explaining patients’ leg symptoms were not fully described and presumed DVTs were only mentioned in the second article in which 6/40 patients would have had a phlebitis (without further descriptions). Hence, we cannot assume 2% to 5% of all DVTs are explained by MayThurner syndrome while others important variables from such a population were not assessed. Another review on lower extremity venous thrombosis diagnosis has also fueled this prevalence information regarding the responsibility of iliac vein compression syndrome in DVTs.4 We should avoid using these unvalidated presumed prevalence numbers that give a false assumption that we understand the possible magnitude of its impact as a risk factor for acute DVTs.