Occult Left Common Iliac Vein Compression Increases Postoperative Venous Thromboembolism Risk Following Total Hip Arthroplasty.

BACKGROUND: Left common iliac vein (LCIV) compression by the right or left common iliac artery (RCIA, LCIA) is known to cause venous thromboembolism (VTE), but the extent to which occult LCIV compression synergizes with lower extremity orthopedic surgery is unknown. We hypothesize that occult LCIV compression is associated with increased VTE risk following total hip or knee arthroplasty (THA, TKA).

METHODS: This case-control study involves all patients at our institution who underwent primary or revision THA or TKA from 2009 to 2017 who had computed tomography or magnetic resonance imaging of the abdomen or pelvis available preoperatively. VTE cases (pulmonary embolism or left-sided deep vein thrombosis) within 30 days of surgery were matched to a control by age, gender, body mass index, Charlson Comorbidity Index, surgical site, and hypercoagulable risk factors. LCIV compression by the right common iliac artery and/or the left common iliac artery was measured in a blinded fashion and was considered present at 50% diameter reduction.

RESULTS: One hundred twelve patients (22 cases, 90 controls) were included for analysis. Nineteen (86.4%) cases and 46 (51.1%) controls demonstrated LCIV compression. The overall sample odds ratio of postoperative VTE in the presence of LCIV compression was 5.97 (95% confidence interval 1.59-33.67, P = .003). In patients who underwent THA (n = 75), LCIV compression was highly predictive of VTE (odds ratio ∞, 95% confidence interval 2.83-∞, P < .001). Compression in the TKA patients did not significantly predict VTE.

CONCLUSION: Compression of the LCIV significantly increases odds of developing postoperative VTE following THA. This effect may suggest a new method of stratifying VTE risk in the orthopedic population to reduce VTE-associated morbidity and mortality.