LAUSR

Objectives: The presence of a proximal venous outflow obstruction (PVOO) in the iliac vein has been observed during catheter-based interventions for acute deep venous thrombosis (DVT). It is not clear whether the proximal obstruction and the more distal DVT are causally related, even though stasis is a commonly known contributor to DVT. Stent placement in the iliac vein, an emerging intervention for chronic PVOO, has provided an unexpected opportunity to evaluate the relationship between PVOO in the iliac vein and DVT. Methods: In order to evaluate a possible PVOO and DVT association, we retrospectively reviewed the medical records of 180 consecutive patients (mean age, 59 years; 57% females), with 90% presenting with edema and 10% presenting with active ulceration, who underwent iliac vein stent placement for chronic PVOO from October 2013 to March 2015. Of these, 152 had partial or complete panels for 48 separate markers of hypercoagulation. We divided the study patients into three groups: no known history of DVT, known history of DVT, and intraoperative findings of DVT as demonstrated by venogram and intravascular ultrasound imaging. Preoperative demographic and comorbidity data were analyzed using independent t-tests and c tests. Focused hypercoagulation profiles consisting of 11 prominent indicators of hypercoagulation were extracted from the broader pool of 48 and used to perform a multiple logistic regression to identify potential predictors of DVT. Results: A total of 77 patients (50.7%) were positive for DVT, but only 26 (17.1%) had a known history of DVT, while 71 (46.7%) had intraoperative findings of a remote DVT. c Tests were significant for increased rates of intraoperative findings of remote DVT in patients with a history of DVT (81% vs 38%; P < .01). c Tests were additionally significant for increased rates of DVT findings in patients with one or more positive hypercoagulation markers (67% vs 42%; P < .01). The most significant predictor for DVT in the logistic regression was a positive result for one of the 11 select hypercoagulation markers (n 1⁄4 148; odds ratio, 2.41; P 1⁄4 .022). Conclusions: PVOO in the iliac veins appears to be associated with DVT, with many of these DVT clinically silent to the patient. Several hypercoagulation markers were found to confer significant predictive value for DVT. This information may aid in management of DVT, PVOO, and patients undergoing vein stent placement for PVOO.