Abstract
Venous thromboembolism (VTE) chemoprophylaxis warrants an individualized, risk-stratified approach, and constitutes a relatively controversial topic in plastic surgery.
The aim of this study was to determine the safety of a 7-day postoperative enoxaparin regimen for VTE prophylaxis compared with a single preoperative dose of heparin in abdominal body contouring surgery.
This single-institution pre-post study investigated the safety of a 7-day enoxaparin postoperative regimen in abdominal body contouring procedures performed by a single surgeon from 2007 to 2018. Four procedures were included: traditional panniculectomy, abdominoplasty, fleur-de-lis panniculectomy, and body contouring liposuction. Group I patients received a single dose of 5000 U subcutaneous heparin in the preoperative period, and no postoperative chemical prophylaxis was administered. Group II patients received 40 mg subcutaneous enoxaparin in the immediate preoperative period, then once daily for 7 days postoperatively.
A total of 195 patients were included in the study, 66 in Group I and 129 in Group II. The groups demonstrated statistically similar VTE risk profiles, based on the 2005 Caprini risk-assessment model. There were no statistically significant differences in the 2 primary outcomes: postoperative bleeding and VTE events. Group I patients had higher reoperation rates (22.7% vs 10.1%, P = 0.029), which was secondary to higher rates of revision procedures.
A 7-day postoperative course of once-daily enoxaparin for VTE risk reduction in abdominal body contouring surgery does not significantly increase the risk of bleeding. Implementation of this regimen for postdischarge chemoprophylaxis, when indicated following individualized risk stratification, is appropriate.
Venous thromboembolism (VTE) events constitute the leading cause of morbidity and mortality in plastic surgery.1-3 Recent studies estimate that the overall incidence of VTE in aesthetic and outpatient plastic surgical procedures ranges from 0.02% to 2%, of which body contouring surgery is associated with the highest risk.4-11
The VTE risk increases significantly when procedures are combined, in the postbariatric surgery population, or in obese patients.11-20 The majority of plastic surgery is outpatient, and high-risk patients with significant comorbidities undergoing plastic surgery in this setting have similar VTE rates to those experienced with inpatient surgery.21
There still remains some controversy among plastic surgeons with regards to VTE prevention, which to a large extent results from the risks associated with the administration of postoperative chemoprophylaxis. There are some data to support the association between commonly used agents such as enoxaparin and higher hematoma rates in abdominal body contouring surgery, as well as data showing a lower incidence of hematomas in the absence of anticoagulants.6,8,22-24
Better data are needed in order to clarify the risks and benefits and develop enhanced evidence-based guidelines for plastic surgeons to optimally individualize VTE risk reduction. The aim of this single-surgeon, single-institution study was to determine the safety and efficacy of a 7-day postoperative enoxaparin regimen for VTE prophylaxis when compared with a single preoperative dose of heparin in abdominal body contouring surgery.
METHODS
Approval for this study was obtained from the Stony Brook University Institutional Review Board. This pre-post study examined the impact of the change in the primary surgeon’s (S.U.K.) practice of chemoprophylaxis in patients undergoing abdominal body contouring surgery, which took place in May 2012. A retrospective chart review was performed of all patients who underwent abdominoplasty, traditional panniculectomy, fleur-de-lis panniculectomy (FDL), and abdominal liposuction by S.U.K. at Stony Brook University Medical Center from June 2007 to January 2018.
Subjects were divided into 2 cohorts according to the regimen of VTE chemoprophylaxis received. Group I received a single dose of 5000 U of subcutaneous heparin in the immediate preoperative period, and no postoperative chemical prophylaxis was administered. These patients underwent body contouring surgery prior to April 2012. All patients treated from May 2012 through January 2018 received 40 mg of subcutaneous enoxaparin, both in the immediate preoperative period and for 7 days postoperatively (Group II).
All patients with incomplete medical records or less than 90 days of follow-up were excluded. Patient demographic characteristics and clinical outcomes were compared between the 2 groups. The Caprini risk-assessment model (2005)25 was utilized for VTE risk stratification. Intraoperative data included the principal operative procedure, secondary concurrent procedures, and operative time. Every procedure was performed under general anesthesia. According to our protocol, every patient was tested for serum nicotine; if this was positive, the surgery was cancelled. A single preoperative dose of intravenous antibiotics was administered prophylactically to every patient.
Our two primary endpoints were the 90-day incidence of VTE and bleeding events. More specific, pulmonary embolus (PE) and deep venous thrombosis (DVT) of the lower or upper extremities constituted VTE events. Bleeding events examined were hemorrhage, defined as anemia requiring transfusion, and clinical evidence of hematoma formation, irrespective of management. Patient data were also collected and analyzed regarding rates of seroma, infection, reoperation, and reoperation requiring readmission.
All categoric demographics and complications were analyzed by chi-squared test. Continuous variables were compared via independent-sample t test. Ordinal variables were compared with the Wilcoxon rank sum test. All analyses were completed with SPSS version 24 (IBM, Armonk, NY). Significance was set at a P value of less than or equal to 0.05 for all statistical tests.
RESULTS
Of the 212 patients who underwent abdominal body contouring procedures, 195 were included in the study, 66 in Group I and 129 in Group II. Seventeen patients were excluded due to insufficient chart documentation or lack of adequate follow-up. One hundred seventy-one (87.7%) patients were female and 24 (12.3%) were male. Their average age was 47.4 years (range, 19–74 years). Mean follow-up time was 226 days (range, 96–2364 days).
Table 1 summarizes the patient demographics. There was no statistically significant difference in the VTE risk profile between the 2 groups. Patients with Caprini scores less than 7 comprised 95.4% and 98.4% of Group I and Group II patients, respectively. There were no differences between the two groups in terms of age, gender, body mass index (BMI), use of oral contraceptives, incidence of diabetes mellitus (DM), family history of VTE, and history of hypercoagulable disorder. The only statistically significant difference was in smoking status: more patients in Group II were former smokers (37.5% vs 18.2%, P = 0.019). There were no active smokers in our cohort.
Patient Demographics
| Group I, N = 66 (%) | Group II, N = 129 (%) | P value | |
|---|---|---|---|
| Mean age [SD], years | 47.7 [11.3] | 47.4 [10.5] | 0.857 |
| Gender | 0.328 | ||
| Male | 6 (9.1) | 18 (14.0) | |
| Female | 60 (90.9) | 111 (86.0) | |
| Mean BMI [SD], kg/m2 | 30.0 [7.4] | 29.4 [6.1] | 0.546 |
| Caprini risk assessment | |||
| Range | 2-9 | 2-10 | |
| Risk | 0.830 | ||
| Low (≤4) | 48 (72.7) | 100 (77.5) | |
| Medium (5–6) | 15 (22.7) | 27 (20.9) | |
| High (≥7) | 3 (4.5) | 2 (1.6) | |
| History of VTE event | 0 | 1 (0.8) | 0.473 |
| Oral contraception | 5 (8.4) | 11 (9.8) | 0.447 |
| Smoking | 0.021 | ||
| Never | 54 (81.8) | 81 (62.8) | |
| Former | 12 (18.2) | 48 (37.2) | |
| Active | 0 | 0 | |
| Diabetes mellitus | 10 (15.2) | 21 (16.3) | 0.839 |
| Family history of VTE | 1 (1.5) | 0 | 0.338 |
| Hypercoagulable disorder | 3 (4.5) | 0 | 0.552 |
| Group I, N = 66 (%) | Group II, N = 129 (%) | P value | |
|---|---|---|---|
| Mean age [SD], years | 47.7 [11.3] | 47.4 [10.5] | 0.857 |
| Gender | 0.328 | ||
| Male | 6 (9.1) | 18 (14.0) | |
| Female | 60 (90.9) | 111 (86.0) | |
| Mean BMI [SD], kg/m2 | 30.0 [7.4] | 29.4 [6.1] | 0.546 |
| Caprini risk assessment | |||
| Range | 2-9 | 2-10 | |
| Risk | 0.830 | ||
| Low (≤4) | 48 (72.7) | 100 (77.5) | |
| Medium (5–6) | 15 (22.7) | 27 (20.9) | |
| High (≥7) | 3 (4.5) | 2 (1.6) | |
| History of VTE event | 0 | 1 (0.8) | 0.473 |
| Oral contraception | 5 (8.4) | 11 (9.8) | 0.447 |
| Smoking | 0.021 | ||
| Never | 54 (81.8) | 81 (62.8) | |
| Former | 12 (18.2) | 48 (37.2) | |
| Active | 0 | 0 | |
| Diabetes mellitus | 10 (15.2) | 21 (16.3) | 0.839 |
| Family history of VTE | 1 (1.5) | 0 | 0.338 |
| Hypercoagulable disorder | 3 (4.5) | 0 | 0.552 |
Patient Demographics
| Group I, N = 66 (%) | Group II, N = 129 (%) | P value | |
|---|---|---|---|
| Mean age [SD], years | 47.7 [11.3] | 47.4 [10.5] | 0.857 |
| Gender | 0.328 | ||
| Male | 6 (9.1) | 18 (14.0) | |
| Female | 60 (90.9) | 111 (86.0) | |
| Mean BMI [SD], kg/m2 | 30.0 [7.4] | 29.4 [6.1] | 0.546 |
| Caprini risk assessment | |||
| Range | 2-9 | 2-10 | |
| Risk | 0.830 | ||
| Low (≤4) | 48 (72.7) | 100 (77.5) | |
| Medium (5–6) | 15 (22.7) | 27 (20.9) | |
| High (≥7) | 3 (4.5) | 2 (1.6) | |
| History of VTE event | 0 | 1 (0.8) | 0.473 |
| Oral contraception | 5 (8.4) | 11 (9.8) | 0.447 |
| Smoking | 0.021 | ||
| Never | 54 (81.8) | 81 (62.8) | |
| Former | 12 (18.2) | 48 (37.2) | |
| Active | 0 | 0 | |
| Diabetes mellitus | 10 (15.2) | 21 (16.3) | 0.839 |
| Family history of VTE | 1 (1.5) | 0 | 0.338 |
| Hypercoagulable disorder | 3 (4.5) | 0 | 0.552 |
| Group I, N = 66 (%) | Group II, N = 129 (%) | P value | |
|---|---|---|---|
| Mean age [SD], years | 47.7 [11.3] | 47.4 [10.5] | 0.857 |
| Gender | 0.328 | ||
| Male | 6 (9.1) | 18 (14.0) | |
| Female | 60 (90.9) | 111 (86.0) | |
| Mean BMI [SD], kg/m2 | 30.0 [7.4] | 29.4 [6.1] | 0.546 |
| Caprini risk assessment | |||
| Range | 2-9 | 2-10 | |
| Risk | 0.830 | ||
| Low (≤4) | 48 (72.7) | 100 (77.5) | |
| Medium (5–6) | 15 (22.7) | 27 (20.9) | |
| High (≥7) | 3 (4.5) | 2 (1.6) | |
| History of VTE event | 0 | 1 (0.8) | 0.473 |
| Oral contraception | 5 (8.4) | 11 (9.8) | 0.447 |
| Smoking | 0.021 | ||
| Never | 54 (81.8) | 81 (62.8) | |
| Former | 12 (18.2) | 48 (37.2) | |
| Active | 0 | 0 | |
| Diabetes mellitus | 10 (15.2) | 21 (16.3) | 0.839 |
| Family history of VTE | 1 (1.5) | 0 | 0.338 |
| Hypercoagulable disorder | 3 (4.5) | 0 | 0.552 |
Operative characteristics are shown in Table 2. In Group I, a higher percentage of patients underwent traditional panniculectomy (42.4%) and liposuction (28.8%) compared with Group II where abdominoplasty (31.3%) and FDL (28.1%) were the 2 most common procedures (P < 0.01). Patients in Group I were also more likely to undergo 1 or more additional procedures compared with Group II, although this value did not reach statistical significance (83.3% vs 65.6%, P = 0.07). In addition, the operative time was similar between the 2 groups (254.0 minutes vs 255.6 minutes, P = 0.932).
Operation Characteristics by Treatment Group
| Group I, N = 66 (%) | Group II, N = 129 (%) | P value | |
|---|---|---|---|
| Procedure | <0.01 | ||
| Traditional panniculectomy | 28 (42.4) | 34 (26.4) | |
| Abdominoplasty | 17 (25.8) | 40 (31.0) | |
| Fleur-de-lis panniculectomy | 2 (3.0) | 37 (28.7) | |
| Liposuction | 19 (28.8) | 18 (14.0) | |
| Combined procedures | 55 (83.3) | 84 (65.1) | 0.08 |
| Admission status | 0.059 | ||
| Inpatient | 36 (54.5) | 52 (40.3) | |
| Outpatient | 30 (45.5) | 77 (59.7) | |
| Mean procedure time [SD], minutes | 254.0 [101.8] | 255.6 [122.4] | 0.930 |
| Group I, N = 66 (%) | Group II, N = 129 (%) | P value | |
|---|---|---|---|
| Procedure | <0.01 | ||
| Traditional panniculectomy | 28 (42.4) | 34 (26.4) | |
| Abdominoplasty | 17 (25.8) | 40 (31.0) | |
| Fleur-de-lis panniculectomy | 2 (3.0) | 37 (28.7) | |
| Liposuction | 19 (28.8) | 18 (14.0) | |
| Combined procedures | 55 (83.3) | 84 (65.1) | 0.08 |
| Admission status | 0.059 | ||
| Inpatient | 36 (54.5) | 52 (40.3) | |
| Outpatient | 30 (45.5) | 77 (59.7) | |
| Mean procedure time [SD], minutes | 254.0 [101.8] | 255.6 [122.4] | 0.930 |
Operation Characteristics by Treatment Group
| Group I, N = 66 (%) | Group II, N = 129 (%) | P value | |
|---|---|---|---|
| Procedure | <0.01 | ||
| Traditional panniculectomy | 28 (42.4) | 34 (26.4) | |
| Abdominoplasty | 17 (25.8) | 40 (31.0) | |
| Fleur-de-lis panniculectomy | 2 (3.0) | 37 (28.7) | |
| Liposuction | 19 (28.8) | 18 (14.0) | |
| Combined procedures | 55 (83.3) | 84 (65.1) | 0.08 |
| Admission status | 0.059 | ||
| Inpatient | 36 (54.5) | 52 (40.3) | |
| Outpatient | 30 (45.5) | 77 (59.7) | |
| Mean procedure time [SD], minutes | 254.0 [101.8] | 255.6 [122.4] | 0.930 |
| Group I, N = 66 (%) | Group II, N = 129 (%) | P value | |
|---|---|---|---|
| Procedure | <0.01 | ||
| Traditional panniculectomy | 28 (42.4) | 34 (26.4) | |
| Abdominoplasty | 17 (25.8) | 40 (31.0) | |
| Fleur-de-lis panniculectomy | 2 (3.0) | 37 (28.7) | |
| Liposuction | 19 (28.8) | 18 (14.0) | |
| Combined procedures | 55 (83.3) | 84 (65.1) | 0.08 |
| Admission status | 0.059 | ||
| Inpatient | 36 (54.5) | 52 (40.3) | |
| Outpatient | 30 (45.5) | 77 (59.7) | |
| Mean procedure time [SD], minutes | 254.0 [101.8] | 255.6 [122.4] | 0.930 |
When analyzing the complication profiles of the 2 cohorts (Table 3), there were no statistically significant differences in our 2 primary outcomes. In terms of postoperative bleeding events, 1 patient in Group I and 4 patients in Group II suffered hematomas (1.5% and 3.1%, respectively, P = 0.507). The patient in Group I suffered the hematoma following traditional panniculectomy and required operative evacuation. Of the 4 patients in Group II with hematomas, 2 required operative intervention, the first patient with an infected hematoma on postoperative day 2 following abdominal and thigh liposuction, and the second patient with a hematoma on postoperative day 6 following an FDL. The remaining 2 Group II patients resolved their hematomas—both following abdominoplasty—without the need for intervention. One patient in each group required transfusion (1.5% and 0.8%, respectively, P = 0.627).
Ninety-Day Incidence of Complications
| Group I, N = 66 (%) | Group II, N = 129 (%) | P value | |
|---|---|---|---|
| VTE | 1 (1.5) | 0 | 0.473 |
| Hematoma | 1 (1.5) | 4 (3.1) | 0.507 |
| Operative evacuation | 1 (1.5) | 2 (1.6) | |
| Resolution without intervention | 0 | 2 (1.6) | |
| Transfusion | 1 (1.5) | 1 (0.8) | 0.627 |
| Infection | 8 (12.1) | 8 (6.2) | 0.154 |
| Seroma | 6 (9.1) | 6 (4.7) | 0.222 |
| Reoperations | 15 (22.7) | 13 (10.1) | 0.027 |
| Scar (and contour) revision | 8 (12.1) | 7 (5.4) | |
| Ischemic skin or soft tissue debridement (including fat necrosis) | 4 (6.1) | 4 (3.1) | |
| Hematoma evacuation | 1 (1.5) | 2 (1.6) | |
| Incision and drainage (infection) | 2 (3.0) | 0 | |
| Readmissions | 3 (4.5) | 2 (1.6) | 0.214 |
| Secondary to reoperation | 2 (3.0) | 2 (1.6) | |
| Monitor of hemodynamic status | 1 (1.5) | 0 |
| Group I, N = 66 (%) | Group II, N = 129 (%) | P value | |
|---|---|---|---|
| VTE | 1 (1.5) | 0 | 0.473 |
| Hematoma | 1 (1.5) | 4 (3.1) | 0.507 |
| Operative evacuation | 1 (1.5) | 2 (1.6) | |
| Resolution without intervention | 0 | 2 (1.6) | |
| Transfusion | 1 (1.5) | 1 (0.8) | 0.627 |
| Infection | 8 (12.1) | 8 (6.2) | 0.154 |
| Seroma | 6 (9.1) | 6 (4.7) | 0.222 |
| Reoperations | 15 (22.7) | 13 (10.1) | 0.027 |
| Scar (and contour) revision | 8 (12.1) | 7 (5.4) | |
| Ischemic skin or soft tissue debridement (including fat necrosis) | 4 (6.1) | 4 (3.1) | |
| Hematoma evacuation | 1 (1.5) | 2 (1.6) | |
| Incision and drainage (infection) | 2 (3.0) | 0 | |
| Readmissions | 3 (4.5) | 2 (1.6) | 0.214 |
| Secondary to reoperation | 2 (3.0) | 2 (1.6) | |
| Monitor of hemodynamic status | 1 (1.5) | 0 |
Ninety-Day Incidence of Complications
| Group I, N = 66 (%) | Group II, N = 129 (%) | P value | |
|---|---|---|---|
| VTE | 1 (1.5) | 0 | 0.473 |
| Hematoma | 1 (1.5) | 4 (3.1) | 0.507 |
| Operative evacuation | 1 (1.5) | 2 (1.6) | |
| Resolution without intervention | 0 | 2 (1.6) | |
| Transfusion | 1 (1.5) | 1 (0.8) | 0.627 |
| Infection | 8 (12.1) | 8 (6.2) | 0.154 |
| Seroma | 6 (9.1) | 6 (4.7) | 0.222 |
| Reoperations | 15 (22.7) | 13 (10.1) | 0.027 |
| Scar (and contour) revision | 8 (12.1) | 7 (5.4) | |
| Ischemic skin or soft tissue debridement (including fat necrosis) | 4 (6.1) | 4 (3.1) | |
| Hematoma evacuation | 1 (1.5) | 2 (1.6) | |
| Incision and drainage (infection) | 2 (3.0) | 0 | |
| Readmissions | 3 (4.5) | 2 (1.6) | 0.214 |
| Secondary to reoperation | 2 (3.0) | 2 (1.6) | |
| Monitor of hemodynamic status | 1 (1.5) | 0 |
| Group I, N = 66 (%) | Group II, N = 129 (%) | P value | |
|---|---|---|---|
| VTE | 1 (1.5) | 0 | 0.473 |
| Hematoma | 1 (1.5) | 4 (3.1) | 0.507 |
| Operative evacuation | 1 (1.5) | 2 (1.6) | |
| Resolution without intervention | 0 | 2 (1.6) | |
| Transfusion | 1 (1.5) | 1 (0.8) | 0.627 |
| Infection | 8 (12.1) | 8 (6.2) | 0.154 |
| Seroma | 6 (9.1) | 6 (4.7) | 0.222 |
| Reoperations | 15 (22.7) | 13 (10.1) | 0.027 |
| Scar (and contour) revision | 8 (12.1) | 7 (5.4) | |
| Ischemic skin or soft tissue debridement (including fat necrosis) | 4 (6.1) | 4 (3.1) | |
| Hematoma evacuation | 1 (1.5) | 2 (1.6) | |
| Incision and drainage (infection) | 2 (3.0) | 0 | |
| Readmissions | 3 (4.5) | 2 (1.6) | 0.214 |
| Secondary to reoperation | 2 (3.0) | 2 (1.6) | |
| Monitor of hemodynamic status | 1 (1.5) | 0 |
One patient in our entire cohort suffered a VTE event. This patient, who was administered 1 dose of 5000 U of subcutaneous heparin preoperatively but did not receive postoperative chemical prophylaxis (Group I), was diagnosed with a PE on postoperative day 2 following a traditional panniculectomy and concurrent hysterectomy. Subsequently, the patient was therapeutically anticoagulated and discharged on apixaban. There were no sequelae and she made a full recovery. None of the Group II patients suffered a VTE event (1.5% vs 0%, P = 0.473).
Although there were statistically more reoperations in Group I patients (22.7% vs 10.9%, P = 0.029), the vast majority were attributed to revision procedures such as skin debridement, fat necrosis excision, and scar revision (Table 3).
DISCUSSION
Abdominal body contouring surgery is associated with significant risk factors predisposing to VTE events, including elevated BMI (over 35 kg/m2), general anesthesia, prolonged operative time, and decreased postoperative ambulation.12,21,26,27 On the other hand, a significant number of plastic surgeons avoid the administration of VTE chemoprophylaxis, in part due to concerns over bleeding.27,28 This underscores the complexity of the issue and the need to investigate further the safety profile of chemoprophylaxis.
The senior surgeon’s change in practice was multifactorial. The PE event in one of his patients, the high number of combination procedures performed, and the increasing number of patients following massive weight loss in his practice led to the implementation of a 7-day postoperative course of once-daily enoxaparin for all patients undergoing abdominal body contouring surgery since May 2012.
Although procedures were combined more often in our study than typically reported in the literature, combined procedures in aesthetic surgery are common. A recent analysis of a database of aesthetic procedures of face, breast, and body in 129,007 patients by Winocour et al11 found the portion of combined procedures to be 32.5%. In addition, they found that body procedures as well as combined surgeries were associated with a significantly higher incidence of VTE than occurred with nonbody and single procedures, respectively.11 Interestingly, in their large study focusing exclusively on outpatient surgery data from the Internet Based Quality Assurance Program (IBQAP), Keyes et al29 failed to find an increased incidence of VTE in abdominoplasty with combined procedures, which is significant as abdominoplasty is associated with the highest rates of VTE among all aesthetic surgery procedures. Here, the only identified predictors of VTE in outpatient abdominoplasty were age greater than 40 years and BMI greater than 25 kg/m2.29
In our study, combined procedures were performed in 55 (83.3%) patients in Group I and 84 (65.1%) patients in Group II. They were combined with laparoscopic or open gynelocologic, urologic, and gastrointestinal surgery in 7 and 4 patients in Groups I and II, respectively. This included the patient (Group I) who suffered a PE following panniculectomy and concurrent hysterectomy.
Expert analyses strongly support the use of the 2005 Caprini score for preoperative VTE risk stratification. Both the American Society of Plastic Surgeons (ASPS) guidelines14 and the American Association of Plastic Surgeons (AAPS) guidelines28 explicitly advocate for individualized VTE risk stratification according to the 2005 Caprini score.
One of the first major studies to find a lower incidence of VTE following the administration of enoxaparin was the Venous Thromboembolism Prevention Study (VTEPS, 2011), which investigated patients in their postoperative inpatient course following plastic and reconstructive surgery under general anesthesia.20,30 However, risk reduction with enoxaparin was only found in the high-risk patients (Caprini score greater than or equal to 7).20,31 Accordingly, the 2012 ASPS Task Force Report recommended postoperative chemoprophylaxis in high-risk patients.14,28,31 Furthermore, this was supported by data from a recent meta-analysis that showed significant VTE risk reduction after surgery with chemoprophylaxis in patients with Caprini scores of 7 to 8 and greater than 8.32
Numerous authors have advocated for the aforementioned recommendation for postoperative chemical prophylaxis in high-risk patients.6,22,28,33,34 Therefore, the risk of bleeding with postoperative chemoprophylaxis warrants discussion. Analysis of the VTEPS data indicates, having controlled for confounding factors, that breast and postbariatric surgeries were risk factors for postoperative bleeding, whereas administration of postoperative enoxaparin was not.20,31 On the other hand, the AAPS meta-analysis revealed an increased risk of postoperative bleeding with low-molecular-weight heparin in the non–risk-stratified plastic surgery population.28 Similarly, the recent all-surgery meta-analysis by Pannucci et al32 showed a significant increase in postoperative bleeding associated with perioperative chemoprophylaxis in non–risk-stratified patients, but failed to identify an association between Caprini score and bleeding risk.
Chemoprophylaxis should be considered on a case-by-case basis in patients who are at a higher risk for bleeding complications, weighing the risks against the benefits by taking into account all comorbid factors.16,28,31,35 Our work has shown that outpatient administration of enoxaparin for a period of 7 days does not lead to a significant increase in postoperative bleeding events, overall and reoperative, when compared with a single preoperative dose of heparin. In addition, all postoperative hematomas in our study were successfully managed, with no sequelae.
Both the optimal duration and dosage of the postdischarge enoxaparin regimen require investigation. We considered the 7-day postoperative administration regimen as a fine equilibrium between clinical benefit, cost, and patient compliance. However, randomized controlled data from research on urologic oncology and major orthopedic surgery have shown benefit without increased bleeding risks with prolonged postoperative enoxaparin administration, for instance up to 35 days.17,18 This is important because the VTE risk extends beyond the perioperative risk, possibly up to 12 weeks.30,33,36 More studies are needed to determine the need for longer postoperative administration in the high-risk plastic surgery patient population.
Furthermore, studies by Pannucci et al19 on plastic and reconstructive surgery patients have shown that the extent of surgical injury and gross body weight independently influence the antifactor Xa (aFXa) levels, thus opening the discussion for a future role of aFXa level monitoring for appropriate enoxaparin dosing and regimen adjustment. Moreover, the ongoing FIxed or Variable Enoxaparin (FIVE) Trial,37 a randomized double-blind clinical trial in plastic surgery inpatients aiming to provide Level I evidence to support the most appropriate enoxaparin dose, has concluded its patient enrollment and data will soon be available.
Because enoxaparin is administered subcutaneously, poor outpatient compliance is a concern among clinicians. Although some investigators have studied oral anticoagulant (aFXa) medications and shown promising results with regards to safety and efficacy,9,38 it is important to note that these medications have not been extensively studied in plastic surgery and do not have Food and Drug Administration (FDA) approval for VTE prevention outside of hip and knee replacement.39,40
The major limitations of this study are the retrospective design and lack of randomization. In addition, this study is underpowered to detect statistical significance for bleeding or VTE. Post-hoc power calculation for bleeding in this study, with event rates of 1.5% in Group I and 3.1% in Group II (made in Stata15 with sampsi 0.015, 0.031; power 0.9), reveals the need for 1966 patients in each group to yield 90% power, which is essentially unfeasible. Given the very low incidence of VTE events, it is very difficult to carry out sample size calculations. Subclinical VTE events were not investigated. Screening ultrasound in the aesthetic population is not standard of care, and according to the 2012 CHEST guidelines, no patient should receive screening duplex ultrasound in the absence of symptoms.36 Future directions would include performing a meta-analysis to pool and analyze data from multiple studies in order to provide definitive conclusions regarding these rare events.
CONCLUSIONS
This study demonstrates that a 7-day postoperative course of once-daily enoxaparin for VTE risk reduction in abdominal body contouring surgery does not significantly increase the risk of bleeding. No significant increase in the hemorrhage or hematoma rates was observed in this study. Implementation of this regimen for postdischarge chemoprophylaxis when indicated following individualized VTE risk stratification is appropriate.
Disclosures
The authors declared no potential conflicts of interest with respect to the research, authorship, and publication of this article.
Funding
The authors received no financial support for the research, authorship, and publication of this article.
REFERENCES
