SLR - May 2019 - Stephen E. Dunham

Venous Thromoboembolism and Bleeding Adverse Events in Lower Leg, Ankle and Foot Orthopaedic Surgery with and Without Anticoagulants

Reference: Heijboer RRO, Lubberts B, Guss D, Johnson AH, Moon DK, DiGiovanni CW. Venous Thromboembolism and Bleeding Adverse Events in Lower Leg, Ankle and Foot Orthopaedic Surgery with and Without Anticoagulants. J Bone Joint Surg Am. 2019 Mar 20;101(6):539–546.

Scientific Literature Review

Reviewed By: Stephen E. Dunham, DPM
Residency Program: Health Alliance Hospital, Kingston, NY

Podiatric Relevance: Patients in the hospital setting undergoing podiatric surgical procedures may have established comorbidities increasing their risk in developing a venous thromboembolism (VTE). It is critical for podiatric surgeons to evaluate these risks and to weigh the advantages and disadvantages in using prophylactic anticoagulants. Current literature is conflicting regarding the use of prophylactic anticoagulants for procedures below the knee. This paper aims to shed light on the development of venous thromboembolisms versus bleeding adverse events for lower-extremity surgical patients under prophylactic anticoagulant therapy.

Methods: This retrospective study compares 5,286 patients who underwent orthopaedic lower-extremity surgery under anticoagulant prophylaxis for primary prevention of VTE versus 5,286 orthopaedic lower-extremity surgery patients who were not. CPT and ICD-9 codes of a tertiary care referral center were reviewed to identify the cohort between August 1, 2005 and July 31, 2015. Patients excluded were those with postoperative follow-up <90 days, presentation of VTE on admission, blood loss or major bleeding at site other than below the knee, nonorthopaedic surgery and use of an antiplatelet drug before or after surgery. Those included were subdivided into four surgical categories: 1) forefoot/midfoot, 2) hindfoot/ankle, 3) lower leg and 4) combination thereof. Primary outcome of interest was symptomatic PE and/or DVT of the lower extremity. Secondary outcome of interest was postoperative bleeding after use of anticoagulants subdivided into Major (fatal, developed in critical organ, required reoperation, fall of hemoglobin >2.0 g/dL or required transfusion >2 units of whole blood or packed cells) and Minor (clinically overt bleeding not meeting Major criteria). Anticoagulants administered were vitamin K antagonists, non-vitamin K antagonists and oral factor Xa inhibitors. Comorbidity data was collected by ICD-9 and status determined by Charlson Comorbidity Index. Propensity Score Matching method was used to minimize selection bias. Logistic regression model was used to establish pairs of patients and were matched on treatment status based on similar propensity score. Statistical analysis was performed to assess distributed data, VTE versus bleeding adverse events, including time from surgery to event, and relationship of VTE and bleeding adverse events to prophylaxis.

Results: No significant difference was noted in the development of a VTE with an anticoagulant versus no prophylaxis in either the forefoot/midfoot (0.2 percent vs. 0.8 percent of cohort, respectively) or the hindfoot/ankle (0.4 percent vs. 1.4 percent of cohort, respectively) groups. A significant difference was identified in the development of a bleeding adverse event with an anticoagulant (2.9 percent of cohort) versus no prophylaxis (1.5 percent of cohort) (P value 0.039) for the forefoot/midfoot surgical group. No significant difference was noted for bleeding adverse events in the hindfoot/ankle surgical group. A three-fold reduction in VTE rate who received anticoagulant prophylaxis was identified though a two-fold increase in risk of bleeding adverse events was present.

Conclusion: Although the authors identify a significant difference within forefoot/midfoot group between increased bleeding adverse events and anticoagulation, they go on to state that ultimately large-scale, prospective studies are necessary to better understand true incidences of these events. For the immediate future, surgeons must continue to weigh the protective benefits versus risk of bleeding adverse events on a case-by-case basis.

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