From the FDA Drug Label
A number of well-controlled clinical trials have demonstrated that low-dose heparin prophylaxis, given just prior to and after surgery, will reduce the incidence of postoperative deep vein thrombosis in the legs The most widely used dosage has been 5,000 units 2 hours before surgery and 5,000 units every 8 to 12 hours thereafter for seven days or until the patient is fully ambulatory, whichever is longer.
The dose of heparin that should be given during plastic surgery free flap is 5,000 units 2 hours before surgery and 5,000 units every 8 to 12 hours thereafter 1.
From the Research
The use of heparin in plastic surgery free flap procedures does not significantly affect flap survival, and its administration should be individualized based on patient factors and bleeding risk, with a typical dose ranging from 1,000 to 5,000 units given intravenously as a bolus before vascular anastomosis, followed by continuous infusion of 500-1,000 units per hour for 3-5 days postoperatively, as suggested by the study 2. The heparin regimen should be adjusted based on coagulation monitoring, typically maintaining an activated partial thromboplastin time (aPTT) of 1.5-2 times normal.
- Heparin administration helps prevent thrombosis at the microvascular anastomosis site by inhibiting thrombin and factor Xa in the coagulation cascade, which is crucial for maintaining flap perfusion and viability.
- The dosing should be individualized based on the patient's weight, comorbidities, bleeding risk, and the specific type of free flap being performed.
- Close monitoring for bleeding complications is essential, and protamine sulfate should be available for reversal if significant bleeding occurs, as noted in the study 3. The study 4 also found that low-dose heparin may not prevent thrombosis and subsequent flap failure to a significant extent, which supports the idea that heparin administration should be individualized and carefully monitored. It's worth noting that the use of anticoagulants and antiplatelet agents in other contexts, such as cardiovascular disease and peripheral artery disease, has been studied extensively, as seen in the studies 5 and 6, but these findings may not be directly applicable to plastic surgery free flap procedures.