VPB1350 - Non-O Blood Type is a Risk Factor for Venous Thromboembolism in Acutely Injured Patients Requiring Orthopaedic Surgery

Background: Patients with a non-O blood type are at increased risk for venous thromboembolism (VTE) based on data from large studies. The association between non-O blood type and major provoked VTE following major orthopaedic surgery is less well defined, especially in trauma patients with different injury types.

Aims: To compare blood group and VTE incidence in trauma patients who require surgical treatment.

Methods: Consecutive adult patients undergoing surgery for acute acetabular, pelvic, hip, femur, or humerus fractures were included in this prospective cohort. Exclusion criteria were prior VTE, pre-injury therapeutic anticoagulation, or pregnancy. Following informed or surrogate consent, patients underwent blood work that included blood typing and were subsequently followed for 3-months. All patients received low-molecular weight-heparin thromboprophylaxis for 14 days post-operatively for upper extremity injuries, or 28 days for pelvic or lower extremity injuries. VTE was defined as symptomatic PE or DVT, or asymptomatic DVT found on screening Doppler ultrasound on postoperative day three. T-tests, chi square and Fisher's Exact tests were used to compare between those with and without VTE and logistic regression was used to evaluate potential risk factors for VTE.

Results: A total of 287 patients were included, with 17 VTE event (5.9%). There were no differences in age and sex between those with and without VTE (Table 1). Compared with type-O, type-A blood carried a 7-fold increased risk for VTE and type-B carried a 6.3-fold increased risk for VTE (Table 2). Compared with a hip fracture, sustaining an acetabular fracture was associated with the highest VTE incidence for fracture type (Table 2).

Conclusion(s): This study supports that non-O blood type is associated with a higher risk of provoked VTE following orthopaedic fracture surgery in trauma patients. Further investigation, including von Willebrand factor and factor VIII levels, is warranted to better understand this relationship.