A Review of Venous Thromboembolism Risk Assessment and Prophylaxis in Plastic Surgery

Nikhil A. Agrawal, M.D.; Kirsty Hillier, M.D.; Riten Kumar, M.D., M.Sc.; Shayan A. Izaddoost, M.D., Ph.D.; Rod J. Rohrich, M.D.

Disclosures

Plast Reconstr Surg. 2022;149(1):121e-129e. 

In This Article

Venous Thromboembolism Prophylactic Regimens

Mechanical Prophylaxis

Mechanical prophylaxis has direct and indirect effects on venous thromboembolism prevention. The pumping movement of the compression device emulates caudal-to-cranial blood flow to prevent venous stasis. Additionally, fibrinolytic activity is augmented with intermittent pneumatic compression.[61] Their ability to reduce the risk of venous thromboembolism is well established and validated in other surgical specialties, but not in plastic surgery.[8] Intermittent pneumatic compression is shown to be more beneficial than elastic compression stockings, and a combination of the two has not been well studied.[24,62] The overall risk of skin irritation, compression neuropathy, compartment syndrome, and falls are all quite low, leading to the use of intermittent pneumatic compression in our patients with higher Caprini scores.

Preoperative Pharmacologic Prophylaxis: Friend or Foe?

Preoperative pharmacologic prophylaxis has risks and benefits. Some argue that preoperative chemoprophylaxis aids in evaluation of a potential bleeding vessel intraoperatively. Campbell et al. administered preoperative chemoprophylaxis in 151 abdominoplasty patients. The patients all used sequential compression devices prior to induction. There was venous thromboembolism and one bleeding event.[63] Durnig and Jungwirth gave rhytidectomy patients heparin 2 hours prior to induction as well as every 24 hours while admitted to the hospital. There were no venous thromboembolism events in 126 patients. However, in the 37 patients in the heparin group, there was a significant hematoma rate of 16.2 percent compared to 1.1 percent in the nonheparin group (p = 0.003).[64]

Pannucci et al. consensus recommendations in 2016 had insufficient data to recommend preoperative heparin for risk reduction. There are no convincing data that preoperative heparin reduces venous thromboembolism risk, but it is clear that there is a risk of bleeding with perioperative heparin in the general plastic surgery and orthopedic surgery literature. In the absence of firm data, starting prophylaxis postoperatively is almost certainly safer.[8,65–67] Many surgeons choose to start heparin 6 hours postoperatively, though this length of time has not been well studied.

The key question is, "What is the acceptable increase in hematoma risk that justifies a drop in venous thromboembolism risk?" The challenge is that this question applies differently to each patient; thus, there is no "one size fits all" answer. In a cosmetic surgery procedure, a takeback for a hematoma is a cash pay procedure that has different implications than insurance-based procedures. Of course, the potential sequelae of a hematoma versus that of venous thromboembolism can be significantly different; thus, in many patients, a significant increase in hematoma risk is justified for a small reduction in venous thromboembolism risk.[2,68]

Pharmacological Venous Thromboembolism Prophylaxis

Determining the appropriate pharmacologic agent to use as prophylaxis is under study (Table 4). Unfractionated heparin has an elimination half-life of 90 minutes, while the half-life of low-molecular-weight heparin is 270 minutes. Therefore, unfractionated heparin could prevent intraoperative venous thromboembolism without the bleeding risk for an extended period after administration. Low-molecular-weight heparin does have a lower risk of heparin-induced thrombocytopenia.[8,63,69] While preoperative chemical prophylaxis is not routinely recommended, when warranted, unfractionated heparin may be better suited for this purpose, while low-molecular-weight heparin is the more logical modality for postoperative anticoagulation.

Real-time laboratory values have been used to determine the best timing and dosing for anticoagulation. In a study of 172 microsurgical patients, Zavlin et al. determined heparin dosing based on intraoperative and postoperative thromboelastography. These patients are generally high risk given their history of cancer, long operative times, hospital admission, and age; however, none suffered venous thromboembolism, and the hematoma rate remained low at 1.7 percent.[70] The thromboelastography is unlikely to be used in an outpatient setting but is readily available in most in-patient hospitals.

Pannucci has done pioneering work determining anti-Xa levels to balance venous thromboembolism and bleeding risk in surgical patients. In the initial study with 94 usable patients, those with a low peak anti-Xa level had a 10.2 percent chance of venous thromboembolism, whereas those with an in-range or high anti-Xa level had no venous thromboembolism.[71] A follow-up study revealed that a set dose of 40mg twice daily maintained adequate anti-Xa levels and reduced venous thromboembolism risk. There was a nonstatistically significant rise in bleeding events (6.8 percent versus 3.2 percent), and they attempted to switch to weight-based dosing for more stringent control. The rise in bleeding events was almost double in a study of only 94 patients, so this dosing strategy needs further evaluation. Weight-based dosing helped avoid low or high anti-Xa levels.[72] Weight-based dosing has been shown to result in predictable outcomes in other specialties.[73] In order to begin the regular use of either thromboelastography or anti-Xa levels, these modalities would need to be verified with other studies prior to widespread use.

Postoperative risk for venous thromboembolism after surgery can exist for up to 6 months.[12] If the data reveal that extended prophylaxis is beneficial for patients, oral alternatives (e.g., apixaban, rivaroxaban, and dabigatran) may provide alternatives more easily administered than injections. Currently, oral anticoagulation use is on-label for prophylaxis only after hip and knee replacements. Interestingly, it is approved for use for 12 days postoperatively in knee replacements and 35 days postoperatively for hip replacements. Additionally, reversal strategies in the setting of bleeding are expensive and not readily available.[74] At this time, more research is needed before a formal recommendation can be made regarding any of the oral anticoagulant agents.

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