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Monday, July 9, 2018

Contralateral DVT after Iliac Vein Stent Placement in May-Thurner Syndrome: location, location, location... 


Summary


Investigators from Inha University Hospital in the Republic of Korea published their analysis on the incidence and potential causes of contralateral deep vein thrombosis (DVT) after common iliac vein (CIV) stenting in patient with May-Thurner syndrome (MTS). Retrospective analysis included 111 patients (women: 73%). Median follow-up was 36 months. Stent location was determined by venogram and classified as extended to the inferior vena cava (IVC), covered the confluence, or confined to the iliac vein. The relationship between stent location and contralateral DVT was analyzed. Potential causes of contralateral DVT were presumed based on venographic findings. Ten patients exhibited contralateral DVT at a median timing of 40 months (9%). Potential causes were venous intimal hyperplasia (VIH) in the distal IVC (n=7), “jailing” of the contralateral CIV (n=2), and indeterminate (n 1⁄4 1). All patients with VIH had previous CIV stents overextended to the IVC. Overextension of CIV stent was associated with contralateral DVT (P < .001). The authors concluded that contralateral DVT after CIV stenting has a relatively high incidence, and overextension of the stent to the IVC wall is associated with contralateral DVT, having VIH as a potential cause.



Fig.1: Categorization of left iliac vein stent position on venogram: (a) extended to the IVC, (b) covered the confluence, and (c) confined to the ipsilateral iliac vein. Arrows indicate tips of stents. Asterisks indicate the confluence. (d) A diagram illustrating the 3 categories of iliac vein stent: 1) overextension, 2) complete confluence coverage, and 3) without confluence involvement.

Commentary


This study helps in understanding the incidence and potential associated factors for contralateral DVT after CIV stenting in patients with MTS. Endovascular stent insertion has been recognized as the treatment of choice for venous outflow obstruction given its safety and effectiveness. Appropriate stent placement is critical for satisfactory long term results, and this study suggests that overextension of the stent into IVC to ensure complete coverage of the lesion may not go unpunished. At the same time research provides plausible explanation for the increased incidence of contralateral DVT. First, persistent insult of the distal IVC wall by the stent struts, leading to VIH. Second, “jailing” of the contralateral CIV disrupting normal blood outflow. On the other hand, not extending the stent into the IVC may prevent complete coverage of the stenotic lesion, causing recurrent ipsilateral symptoms. It would be interesting to see a comparison of freedom from target lesion recanalization (FLR) between those 3 groups with different stent position. Nonetheless, the study highlights the importance of appropriate stent placement. Utilization of additional imaging guidance such as intravascular ultrasound should be common practice, and industry must continue to improve device design to ensure better biocompatibility and precise deployment.

Click here for abstract

Le TB, Lee TK, Park KM, Jeon YS, Hong KC, Cho SG. Contralateral Deep Vein Thrombosis after Iliac Vein Stent Placement in Patients with May-Thurner Syndrome. J Vasc Interv Radiol. 2018 Jun;29(6):774-780.

Post Author:
Ricardo Yamada, MD
Assistant Professor
Department of Radiology
Division of Vascular and Interventional Radiology
Medical University of South Carolina

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