May-Thurner Syndrome and Other Pelvic Vein Compression Syndromes: Early Detection with Duplex Ultrasound and Venography

Abstract

Research Question: This study aims to identify duplex ultrasound and venography imaging findings that can identify May-Thurner Syndrome (MTS) and other pelvic vein compression syndromes at an earlier stage of disease for adults with lower extremity leg pain and edema. This aim is achieved by investigating if reflux, abnormal flow patterns, spontaneity, phasicity, or competency on duplex ultrasound predicts venous compression on intravascular ultrasound (IVUS). Spontaneity, compressibility, and competency on duplex ultrasound at the common femoral vein are also researched for predictability of venous compression on IVUS. Compression on venography is also evaluated for its predictability of venous compression on IVUS.

Background, Significance, and Rationale: May-Thurner Syndrome (MTS) and other pelvic vein compression syndromes are usually diagnosed late in the disease course given the absence of reliable non-invasive diagnostic imaging. This leads to worse clinical outcomes which is on a spectrum of venous ulcers to recurrent thromboses or amputation. Additionally, this contributes to the economic impact of chronic venous diseases that is estimated to cost $5 billion in the United States. Research in biofluid mechanics and vascular pathology have demonstrated that alterations in intravascular hemodynamics contribute to pathophysiological changes and adaptations. A small study demonstrated that MTS might be detected earlier than is currently practiced by focusing on specific duplex ultrasound findings. The present investigation builds on both the small study and established physical principles of fluids and sound to shape its theoretical basis and clinical application to the imaging modalities of interest.

Materials and Methods: This study selected 237 patients over a 7-year period that presented with lower extremity pain and edema who were also found to have venous compression. This study occurred at a single center that contained an endovascular AngioSuite in Dallas, Texas and patient data was obtained from the electronic medical record, duplex ultrasound studies, venography studies, and IVUS studies. Since most variables of interest were categorical, data was analyzed using logistic regression on the R statistical software and the criteria to reject the null hypotheses was set to an alpha level of p < 0.05.

Results: Statistical measures between males and females show nearly symmetric and platykurtic distributions with similar risk factors. Data from Venography and IVUS showed high relative frequencies of = 50% stenosis for multiple vessels. Data analysis identified that spontaneity that is either reduced, absent, or pulsatile, compressibility that is reduced, and the presence of thrombosis predict compression on venography. Analysis also indicated that the absence of reflux and normal competency on duplex ultrasound predict compression on IVUS.

Conclusions: In conclusion, MTS and other pelvic vein compression syndromes are often diagnosed late which causes poor clinical outcomes and increases healthcare expenditures. This single center study investigated imaging modalities on the basis of a small previous study and principles of physics, and suggests predictors of = 50% stenosis on IVUS.