Low-Molecular-Weight Heparins in Thromboprophylaxis After Major Orthopedic and Traumatological Procedures According to Current Recommendations
Patients after major orthopedic and traumatological procedures are at high risk of thromboembolic disease. This is especially true for people undergoing hip and knee replacement or patients with a proximal femur fracture and severe lower limb injury. The routine implementation of pharmacological thromboprophylaxis, such as low-molecular-weight heparins, is currently the gold standard in perioperative care in these cases.
Introduction
Thromboembolic disease (TEN) is one of the most common complications after major orthopedic and traumatological procedures. Without the use of any thromboprophylaxis methods, the incidence of deep vein thrombosis in hospitalized patients after major orthopedic procedures reaches 40–60% and the incidence of fatal pulmonary embolism 2–3%, after surgeries for proximal femur fractures up to 7%.
The etiopathogenesis of TEN in these patients is complex, with risk factors including the use of a tourniquet during the surgical procedure, immobilization in the perioperative period, vascular endothelial injury during the surgery, increased levels of thromboplastin after trauma, and an increased hypercoagulable state due to the use of polymethylmethacrylate bone cement.
The introduction of mechanical and pharmacological thromboprophylaxis into routine care has been proven to reduce the risk of deep vein thrombosis by at least 50% with sporadic cases of pulmonary embolism. A range of prophylactic drugs from different groups are currently available within pharmacological thromboprophylaxis. According to the current recommendations of the American College of Chest Physicians (ACCP), low-molecular-weight heparins (LMWH) are preferred after total hip and knee replacement and surgery for proximal femur fractures. Other methods of pharmacological thromboprophylaxis are recommended as alternative therapies.
The administration of LMWH is also one of the modalities of pharmacological thromboprophylaxis according to the updated guidelines of the Czech Angiological Society ČLS JEP (ČAS), which were published in 2020. The recommendations of ACCP and ČAS largely agree on the indications and methods of thromboprophylaxis administration.
Current Recommendations in Thromboprophylaxis
For total hip replacement, LMWH prophylaxis should be initiated either at least 12 hours before surgery or at least 12 hours after its completion. It should be administered every 24 hours for 28–35 days. According to ČAS, this recommendation is intended for patients with a body weight of 40–100 kg and creatinine clearance of ≥ 30 ml/min. For patients with parameters outside these limits, dose adjustment or the use of an alternative prevention option for thromboembolic disease is required. The advantage of low-molecular-weight heparins is the possibility of leaving an epidural catheter in place during the postoperative period.
The same recommendations apply to proximal femur fractures. According to ČAS, if surgery is delayed, LMWH treatment should be initiated immediately upon hospital admission, and the optimal interval between the last LMWH dose and the surgery should be approximately 12 hours.
For total knee replacement, the recommendation for LMWH administration is the same as for the hip, but the duration of administration is usually 14 days. Prolonged prophylaxis is recommended for patients with a history of TEN or with the accumulation of other thrombosis risk factors. The ACCP recommendations prefer LMWH in total hip and knee replacement over other anticoagulants.
According to ČAS recommendations, for patients after major orthopedic trauma with active bleeding or a high risk of bleeding, mechanical means of thromboprophylaxis are recommended first. LMWH should start being administered after the risk of major bleeding has subsided. LMWH prophylaxis should continue until hospital discharge, including the stay in the rehabilitation facility. In cases of persistent immobility, it is recommended to continue prophylaxis with LMWH or warfarin even in the subsequent period.
In the case of spinal cord injury with incomplete spinal cord lesion, CT or MRI examination is necessary to exclude perispinal hematoma according to ČAS recommendations. If a hematoma is found, mechanical means of thromboprophylaxis are recommended first. After verifying hematoma stabilization with CT/MRI after several days, LMWH administration is recommended. LMWH prophylaxis is also recommended in the case of complicated spinal operations (malignancy, history of TEN, lower limb weakness), once daily with therapy starting the day after the surgical procedure. The ACCP recommendations also list advanced age and anterior surgical approach to the spine as risk factors.
Conclusion
According to current international and domestic recommendations, low-molecular-weight heparins play an important role in the prevention of TEN in the perioperative period after major orthopedic and traumatological procedures. According to the American College of Chest Physicians, LMWHs should be preferred over other classes of anticoagulants, while the recommendations of the Czech Angiological Society ČLS JEP present them as one of the viable options for pharmacological thromboprophylaxis.
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Sources:
1. Flevas D. A., Megaloikonomos P. D., Dimopoulos L. et al. Thromboembolism prophylaxis in orthopaedics: an update. EFORT Open Rev 2018; 3 (4): 136–148, doi: 10.1302/2058-5241.3.170018.
2. Hirmerová D., Karetová D., Malý R. a kol. Akutní žilní trombóza: současný stav prevence, diagnostiky a léčby. Doporučený postup České angiologické společnosti ČLS JEP. Aktualizace 2020. Česká angiologická společnosti ČLS JEP, 2020. Available at: www.angiology.cz/Angiology/media/system/guidelines/DP_CAS_akutni_zilni_tromboza_2020.pdf
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