What are the alternatives for Deep Vein Thrombosis (DVT) prophylaxis before gastric bypass surgery in a patient with a porcine (pork) allergy?

From the Guidelines

For DVT prophylaxis before gastric bypass surgery in a patient with a pork allergy, I recommend using direct oral anticoagulants (DOACs) like rivaroxaban (Xarelto) 10 mg daily or apixaban (Eliquis) 2.5 mg twice daily, as they are synthetic, safe, and effective alternatives. These options are completely synthetic and contain no pork-derived components, making them safe for patients with pork allergies. Traditional heparin and many low molecular weight heparins (LMWHs) should be avoided as they may contain pork-derived components or be processed using porcine intestinal mucosa 1.

Key Considerations

• Mechanical prophylaxis with sequential compression devices should also be used in conjunction with pharmacological methods, as combining may reduce VTE events (RR 0.05,95% CI 0.00–0.89; NNT=9; 1 study, 150 participants; low-certainty) 1.
• The prophylaxis should typically continue for 10-14 days post-surgery for standard risk patients, or up to 28 days for high-risk patients, as the evidence on major bleeding, all-cause mortality, and VTE-related mortality is uncertain (effect not estimable or very low-certainty evidence) 1.
• Before initiating any anticoagulant, assess the patient's renal function and bleeding risk, as dosage adjustments may be necessary for patients with impaired kidney function.
• Current evidence shows that there is probably a similar effect between DOACs and conventional anticoagulants in the prevention of recurrent VTE, DVT, and death, but DOACs reduced major bleeding compared to conventional anticoagulation 1.

Additional Recommendations

• Synthetic fondaparinux (Arixtra) at a dose of 2.5 mg subcutaneously once daily, starting 6-8 hours after surgery, can also be considered as an alternative option.
• It is essential to weigh the benefits and risks of anticoagulant therapy in each patient, considering their individual risk factors for VTE and bleeding.

From the FDA Drug Label

1. 1 Prophylaxis of Deep Vein Thrombosis Fondaparinux sodium injection is indicated for the prophylaxis of deep vein thrombosis (DVT), which may lead to pulmonary embolism (PE): in patients undergoing hip fracture surgery, including extended prophylaxis; in patients undergoing hip replacement surgery; in patients undergoing knee replacement surgery; in patients undergoing abdominal surgery who are at risk for thromboembolic complications.

Fondaparinux can be used for DVT prophylaxis before gastric bypass surgery as it is indicated for patients undergoing abdominal surgery who are at risk for thromboembolic complications.

• The recommended dose is 2.5 mg administered by subcutaneous injection once daily after hemostasis has been established.
• The initial dose should be administered no earlier than 6 to 8 hours after surgery.
• Since fondaparinux is not derived from pork, it can be used in patients who are allergic to pork 2.

From the Research

DVT Prophylaxis Options for Gastric Bypass Surgery

For patients undergoing gastric bypass surgery who are allergic to pork, several alternatives can be considered for DVT prophylaxis:

• Apixaban, a direct oral anticoagulant, has been shown to be safe and effective in preventing thromboembolic events after bariatric surgery 3.
• The use of mechanical prophylaxis, such as external compression devices, in combination with medical management and early ambulation, can also be effective in preventing DVT 4.
• Other direct oral anticoagulants, such as rivaroxaban and dabigatran, may also be considered, although their efficacy in patients with significantly altered gastrointestinal tracts is uncertain 5.

Considerations for Bariatric Surgery Patients

When selecting a DVT prophylaxis option for bariatric surgery patients, several factors should be considered:

• The type of bariatric surgery being performed, as some procedures may affect the absorption and efficacy of certain anticoagulants 5, 6.
• The patient's individual risk factors for DVT and PE, such as history of DVT, transfusion, and operative length 7.
• The potential for interactions between anticoagulants and other medications, as well as the risk of side effects and complications 3, 6.

Pharmacokinetics and Pharmacodynamics of Apixaban

Studies have investigated the pharmacokinetics and pharmacodynamics of apixaban in bariatric surgery patients:

• Apixaban has been shown to have minimal effects on PK and PD parameters after bariatric surgery, although factor X activity may be decreased postoperatively 6.
• The efficacy and safety of apixaban in preventing thromboembolic events after bariatric surgery have been demonstrated in large-scale studies 3.