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.


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

In This Article

Caprini Score Variables That are Missing or Require Further Study

The Caprini score is a pivotal point for further clinical decision making. If the score is 8 or higher, the patient should be considered for pharmacologic prophylaxis, risk factor modification, or avoidance of surgery. Concurrently, the surgeon must consider a variety of other patient and surgery specific factors to guide the clinical decision for pharmacologic prophylaxis.

Effect of Type of Anesthesia on Venous Thromboembolism Rate

The Caprini score was validated in patients who had general endotracheal anesthesia.[24,25] General endotracheal anesthesia halts the lower extremity muscle pump system, creating venous stasis, a key component to Virchow's triad. Alternatives to general endotracheal anesthesia, such as monitored anesthesia care and epidural anesthesia, are utilized for many elective plastic surgery procedures. A study of abdominoplasty patients in Iran evaluated differential epidural nerve blocks, which can spare the muscle pump function of the lower extremities. No venous thromboembolism occurred in patients who had epidural anesthesia. Of note, however, is that 4.8 percent of patients failed epidural anesthesia, and an undisclosed number of patients required a blood patch for a dural puncture.[26] More robust evaluations of differential epidural anesthesia risks are needed prior to widespread use. Reinisch et al. evaluated patients who underwent face lifts without pharmacologic prophylaxis, and 60 percent had neither mechanical nor pharmacologic prophylaxis. The overall incidence of venous thromboembolism was about 0.5 percent in 9937 patients. General endotracheal anesthesia was associated with a 6.7-fold increased risk of venous thromboembolism compared to procedures done under local anesthesia or intravenous sedation (p < 0.05). Additionally, the use of intermittent compression device was associated with a significantly decreased risk of venous thromboembolism compared to elastic bandage wraps and no interventions (p < 0.01).[27]

Eric Swanson proposed a style of anesthesia consisting of Spontaneous breathing, Avoidance of inhalational anesthesia, Face up, and Extremities mobile (SAFE) to reduce venous thromboembolism risk. He utilizes a laryngeal mask airway and avoids paralysis, given that there is no evidence that paralysis is needed for adequate plication of an abdominoplasty.[28] In 2020, his group studied 1000 patients using this technique and used ultrasound surveillance of the deep veins of the lower extremities for every patient before surgery, the day of surgery, and 1 week after surgery. The argument is that that early detection of asymptomatic deep vein thrombosis can help determine which patients should be anticoagulated.[28] This method is attractive since most outpatient plastic surgery patients will not require anticoagulation, and there is no increase in hematoma risk with this method.[29] Only 24.7 percent of patients received mechanical prophylaxis, and anticoagulation was given for venous thromboembolism diagnosed on ultrasound. The venous thromboembolism rate was 0.9 percent, and one patient developed a pulmonary embolism. Interestingly, patients utilizing sequential compression devices had the same venous thromboembolism rate as those who did not, though this assertion was likely underpowered.[30] The current studies need to be replicated and corroborated by other surgeons prior to recommendations utilizing this strategy.

The Caprini score does not consider the protective effect of anesthesia without muscle relaxation while under monitored anesthesia care or epidural anesthesia. In order to calculate the full protective effect, the odds ratio for venous thromboembolism risk when undergoing general endotracheal anesthesia in comparison to monitored anesthesia care needs to be studied.[24,30]

Long Haul Travel

Long haul travel (airline or car travel for more than 4 hours) immediately after plastic surgery must be considered as a risk factor. There is strong evidence that long haul travel is associated with a 2- to 4-fold increased risk for deep vein thrombosis/pulmonary embolism in the general population.[31] The LONFLIT (Long-Haul Flights deep vein thrombosis) studies show that trans-oceanic flights come with a 4.5 percent risk of asymptomatic deep vein thrombosis developing in high-risk patients; however, surgery in the past 6 months was an exclusion criterion.[32] That risk dropped to 0.25 percent when patients wore below-knee compression socks of 25 mmHg during the flight.[33] Treatment with aspirin did not have a significant effect on development of venous thromboembolism, while those receiving a single dose of low-molecular-weight heparin had no venous thromboembolism. Blood stasis, dehydration, and hypobaric hypoxia are also potential factors that can lead to venous thromboembolism; thus, those in high-risk groups should stay well hydrated and stretch and move each hour and consider ankle compression stockings.[34]

Hormone Replacement Therapy, Contraception, and Selective Estrogen Receptor Modulation

Supplemental estrogen used for hormone replacement therapy or oral contraceptive pills is included in the Caprini score. Estrogen increases the activity of procoagulant factors II, VII, X, and XII and fibrinogen while decreasing the activity of anticoagulants antithrombin, protein C, and protein S. The thrombotic effect of progesterone is unclear but it may cause resistance in activated protein C or venous stasis related to progesterone receptors in veins.[35] Interestingly, evidence demonstrates that the increase in venous thromboembolism risk with hypertension and high body mass index is actually higher than that of estrogen.[36,37] Combined oral contraceptive pills do increase the risk of venous thromboembolism; however, progesterone-only contraception confers a very low increased risk.[38] For hormone replacement therapy, estrogen-only as well as estrogen-progesterone combined therapy significantly increase venous thromboembolism risk.[39]

Given the lack of data from randomized trials, or even prospective cohort studies, making evidence-based guidelines on holding estrogen therapy before surgery is difficult. Normalization of coagulation abnormalities associated with oral contraceptives takes 4 to 6 weeks.[40] Therefore, a reasonable approach in patients with a Caprini score of 8 or higher would be to hold estrogen-only or combined contraceptive therapy for 4 weeks before surgery and resume 2 weeks after surgery. Risk of pregnancy needs to be weighed against the risk of thrombosis, and patients should be counseled on using alternative, barrier contraceptives. With regard to postmenopausal women on hormone replacement therapy, an acceptable alternative to systemic therapy would be local therapy during the perioperative period using transdermal creams. The creams have no increased risk of venous thromboembolism even when combined.[40,41]

Tamoxifen is a selective estrogen-receptor modulator sometimes used for breast cancer suppression for 5 years, and there is significant evidence for thrombus formation. Tamoxifen does increase the venous thromboembolism risk by five times for the first 3 months of therapy, and then it levels off to about two times for the duration of treatment.[42] Limited data suggest that stopping tamoxifen 3 weeks prior to surgery will mitigate the risk.[43] There is mixed evidence regarding the effects of tamoxifen on free flap vascular compromise, but risk may be averted by stopping tamoxifen 2 to 3 weeks prior to surgery.[44,45] By contrast, aromatase inhibitors, which have a similar indication, do not demonstrate an increase in venous thromboembolism risk.[46]

Type of Surgery

The type of procedure may have an effect on venous thromboembolism incidence. Positioning in the flexed position and plication theoretically increase the pressure in the iliac veins and create venous stasis. Winocour et al. found that trunk, abdomen, and extremity procedures have the highest rate of deep vein thrombosis, while face and breast procedures were lowest. More than 50 percent of the venous thromboembolism events in the study were in abdominoplasties.[23] Their findings are consistent with other data, including a recently published systematic review.[47]

Venous thromboembolism risk in breast reconstruction has also been extensively studied. Subichin et al. evaluated patients with breast reconstruction with similar comorbidities and stratified venous thromboembolism risk based on the type of reconstruction. Pedicled transverse rectus abdominis myocutaneous (TRAM) reconstruction was an independent risk factor for venous thromboembolism in 300 patients.[48] Despite receiving preoperative and postoperative chemical prophylaxis, Sultan et al. found a 6.8 percent venous thromboembolism risk in patients undergoing microsurgical abdominally based breast reconstruction.[49] More recent studies have shown the risk in microsurgical breast reconstruction to be as low as 1.3 percent, with most occurring after discharge. Interesting risk factors included the patient's Elixhauser score, length of stay, and a history of venous thromboembolism.[17]

Tranexamic Acid

Tranexamic acid has gained popularity and is used in a variety of surgical procedures, including hip and knee replacements,[50] cardiac surgery,[51] trauma management,[52] craniosynostosis correction,[53] face lifts,[54] rhinoplasty,[55] and massive weight loss surgery.[56] Tranexamic acid prevents the conversion of plasminogen to plasmin, thereby preventing the breakdown of clot. It also blocks plasmin-induced platelet activation, which allows for a longer duration of platelet activation. It can have a hemostatic effect for up to 17 hours.[57]

Tranexamic acid is administered orally, topically, or intravenously with different venous thromboembolism risk profiles. In a meta-analysis of 276 rhinoplasty patients, tranexamic acid was used intravenously or orally, and there were no thromboembolic events and significant reductions in edema and ecchymosis.[55] In low-risk procedures, such as face lifts and craniosynostosis, there was also a low associated venous thromboembolism risk.[53,54,57]

The effects on high-risk patients undergoing body contouring procedures or free flaps require further study. While there are no adequately powered studies on high-risk plastic surgery patients, intravenous tranexamic acid is associated with a three times higher venous thromboembolism risk in trauma patients.[58] Ausen et al. evaluated the plasma concentration of tranexamic acid in patients after topical versus intravenous administration of tranexamic acid in abdominoplasty patients. The intravenous group had plasma concentrations more than 10 times greater than those of the other groups.[56] These data agree with meta-analysis studies in orthopedic surgery with patients undergoing total joint replacements.[59,60] Therefore, topical administration may offer an acceptable alternative with similar efficacy. In the absence of firm data regarding plastic surgery patients with high Caprini scores, it would be prudent to avoid intravenous tranexamic acid in these patients. There is insufficient evidence regarding oral administration to make a recommendation.

Validating the risks of general anesthesia, office-based ultrasound, flying, hormone replacement therapy, type of procedure, and use of tranexamic acid represents the next frontier in determining how to manage venous thromboembolism risk in plastic surgery. When patients have a Caprini score equal to or greater than 8, the above risk factors should be taken more seriously and modified when possible (Table 3).