Abstract No. 384 Predicting Inferior Vena Caval Thrombosis in Patients with Iliofemoral Deep Venous Thrombosis Undergoing Thrombectomy

Endovascular treatment of iliofemoral deep venous thrombosis (DVT) can reduce the incidence of post thrombotic syndrome. In patients undergoing endovascular treatment, inferior vena caval (IVC) extension of DVT can affect procedural planning and equipment decisions. Routine workup of DVT with duplex venous ultrasonography is not sensitive for identifying IVC thrombosis. While computed tomography venography (CTV) is highly sensitive and specific for IVC thrombosis, its role in the routine workup of DVT is non-standardized due to additional costs and radiation exposure. The purpose of this study is to delineate clinical factors that predict IVC extension of iliofemoral DVT and identify patients that may benefit from CTV prior to intervention. Retrospective review was performed of all patients who underwent endovascular treatment of iliofemoral DVT at our institution from May 2019 to August 2023. Initial imaging studies, including venous duplex ultrasonography, invasive venography and CTV (when available) were reviewed to identify the presence of IVC thrombus. Independent variables that were evaluated included patient age, gender, presence of unilateral versus bilateral DVT, presence of provoking factors, presence of IVC filter, history of malignancy, and history of prior DVT. Bivariate and multivariate statistical analysis with Fisher's exact tests and logistic regression was performed. 110 patients with a mean age of 64 years who underwent DVT thrombectomy during the study period were included. 26/110 had bilateral DVT, 62/110 patients had provoked DVT, 24/110 patients had a history of malignancy, and 41/110 patients had a history of DVT. A total of 27/110 patients had caval thrombosis. 19/26 (73.1%) patients with bilateral DVT had caval thrombosis while 8/84 (9.5%) patients with unilateral DVT had caval thrombosis (RR 7.7, OR 63.4, p < 0.001). 15/17 (88%) patients with IVC filter had caval thrombosis while 12/93 (13%) patients without IVC filter had caval thrombosis (RR 6.8, OR 99.0, p < 0.001). Clinical factors not significant associated with IVC thrombosis included gender (RR 0.73, p = 0.38), provoked DVT (RR 1.02, p = 1.0), history of malignancy (RR 0.83, p = 0.79) and history of DVT (RR 1.56, p = 0.25). Presence of bilateral DVT and presence of IVC filter are two factors associated with significantly higher incidence of caval thrombosis in patients undergoing catheter-directed therapy for iliofemoral DVT. These patients would benefit from CTV prior to intervention to optimize pre-procedural planning and patient outcomes.