Risk of Thromboembolism Following Body-Contouring Surgery After Massive Weight Loss

METHODS

A retrospective analysis of all patients undergoing body-contouring surgery after massive weight loss between January 2004 and August 2012 was performed. The surgery was usually completed in stages. Data were collected by 2 authors independently (M.G. and N.M.), and any discrepancies were resolved by consensus. Data that were collected included patient demographics, patient care pathways, perioperative events and any postoperative complications, length of hospital stay, discharge plans, and the nature and number of further operations. VTE prophylaxis pre- and postoperatively, including chemical and mechanical prophylaxis, was also recorded.

Prior to surgery, patients were stratified according to their VTE risk into low, medium, or high risk, based on patient and surgical factors (Table 1). Different patient and surgical factors are given individual scores and then summed together to gain the overall score. Depending on their risk stratification score, they would receive an appropriate VTE prophylaxis regimen (Table 2). Patients were followed up until the time of final discharge (all being >12 months). If a patient receives a score of 3, and hence is considered to be at high risk for VTE, hematology would be consulted to assess this patient's suitability for surgery.

RESULTS

One hundred thirty-five procedures were carried out on 53 patients over the 7-year period from January 2005 to August 2012. The cohort included 43 female and 10 males, with an average age of 44 years (range, 23–59 years). Fifty-five abdominoplasties, 31 thigh lifts, 23 brachioplasties, 12 mastopexies, and 14 lower-body lifts were carried out during the study period. Table 3 shows a range of comorbidities and ASA (American Society of Anesthesiologists) scores in the patient group. Weight loss prior to body contouring was due to gastric bypass in 18 patients, gastric banding in 20 patients, and diet and exercise in 15 patients. The mean body mass index (BMI) prior to their weight loss procedure was 44.8 kg/m² (range, 30.9–60.9 kg/m²), and mean BMI prior to body contouring was 28.2 kg/m² (range, 24–44 kg/m²). This led to a mean excess weight loss of 36% prior to the body-contouring procedure (range, 20%–50%).

Each patient had a mean of 3 body-contouring procedures (range, 1–6), with an overall mean operative time of 3.68 hours (range, 2–7 hours). All patients received intravenous antibiotic prophylaxis at induction. Mean inpatient stay was 4 days (range, 2–14 days). The average total time under the care of plastic surgery was 32 months (SD = 19) and from initial bariatric surgery referral to discharge from plastic surgery was 96 months (SD = 26).

DISCUSSION

The purpose of this study was to assess the risk of DVT and PE following body-contouring surgery after massive weight loss. With the increase in the number of body-contouring procedures, it is important for surgeons to be able to predict whether patients are at a greater risk of postoperative complications, so they can select the most appropriate treatment option.

A recent survey by the American Society of Plastic Surgeons revealed that for postbariatric body-contouring surgery, DVT has occurred in more than one third of plastic surgeons’ practices, with 7% of surgeons reporting a patient death from PE, and the authors concluded that more studies are required in this field to improve patient care and safety.⁷ There is a lack of clear guidance for the prevention of VTE in plastic surgery. Grazer and Goldwyn⁴ reported an incidence of 1.2% for DVT and 0.8% for PE in a series of abdominoplasties. Other studies have shown that the incidence of VTE rises when abdominoplasties are combined with another intra-abdominal procedure, with incidence rising up to 6.6%.⁸ It seems reasonable to assume that VTE complications would be higher in patients undergoing body-contouring surgery for the following reasons: (1) the length of procedures; (2) incidence of PE, which rises to 3.5% in obese and bariatric patients even when using heparin prophylaxis; and (3) decreased venous return from the lower extremity due to intraoperative positioning.⁹

Understanding the effect of obesity on the risk of postoperative surgical complications is of great importance to the surgical field. Harth et al¹⁰ observed obese patients who underwent hernia repair and found an increased wound complication rate after concurrent ventral hernia repair and panniculectomy, with an odds ratio of 5.4 (P = .04). Fischer et al¹¹ similarly found that obesity was a risk factor for major operative morbidity after abdominal wall reconstruction in 1081 patients. Similarly, Fisher et al¹² observed that ventral hernia repair and panniculectomy in states of extreme obesity (BMI ≥45.0 kg/m²) is associated with a higher incidence of complications and as such staged procedures should be given consideration. Systemic surgical complications including DVT/PE have also been reviewed in obese patients. Nelson et al¹³ reviewed the 2005–2010 American College of Surgeons National Surgical Quality Improvement Program database and identified the cases of abdominal wall reconstruction and examined early complications in the context of obesity. Pulmonary embolism incidence was nearly 10 times higher in obese patients (2.1% vs 0.2%; P = .001) and as such VTE overall was additionally significantly higher (2.8% vs 0.8%; P = .006).¹³

The risk of surgical complications after body-contouring surgery for the bariatric versus nonbariatric patients has been reported to be higher. Greco et al performed a large retrospective study in 222 patients and observed a greater risk of wound surgical complications after abdominoplasty and panniculectomy in bariatric patients (n = 139) than in nonbariatric patients (n = 83) (41% vs 22%; P < 0.01).¹⁴ Similarly, early complications were significantly higher in postbariatric patients (48%) than in patients who had not had weight loss surgery (29%) in 161 patients undergoing abdominoplasty.¹⁵ However, a prospective study illustrated no evidence for an association between the weight loss method and risk in patients undergoing body-contouring surgery in 34 procedure-matched case controls.¹⁶ Further studies that examined the risk of DVT/VTE, specifically after body contouring, have also been carried out. Reish et al¹⁷ found no clinically detected DVT in 105 patients of whom 62% had massive weight loss. In this study, high-risk patients received 5000 units of low-dose unfractionated heparin (LDUH) preoperatively and 5000 units of LDUH 8 to 24 hours postoperatively with the addition of pneumatic compression devices.¹⁷ In a cohort of 3334 patients, of whom 229 patients had massive weight loss, Pannucci et al¹⁸ illustrated a risk reduction in high-risk patients on using enoxaparin 6 to 8 hours postoperatively. Including this study, the literature to date illustrates a low detection rate of VTE in patients undergoing body-contouring surgery after massive weight loss. Current studies have also documented that the rate of VTE after bariatric surgery is less than 1%, which is similar to the low VTE risk after body contouring.¹⁹ In our series, we have shown a prevalence of VTE of 1.89% after body-contouring procedures. A recent meta-analysis by Hasanbegovic and Sørensen²⁰ reviewed the postoperative complications after body-contouring surgery after weight loss. Seven studies were found to be eligible to be included in the study. The meta-analysis revealed that 60% to 87% patients had increased risk of having a postoperative complication, having previously undergone weight loss surgery compared with weight loss after dietary changes or exercise.²⁰ The authors concluded that local complications, such as hematoma, infection, seroma, and dehiscence, were high, whereas systemic complications, such as DVT or PE, were rare, with only 1 study showing evidence of DVT in postbariatric patients (2/23).²⁰

The correct type, dosage, and timing of chemoprophylaxis for the surgical patient population remain a controversial topic in both the literature and ordinary daily practice. LMWH has been found to be an effective chemoprophylaxis in general surgery and orthopedic surgery patients and recently for plastic surgery.²¹ Seruya et al²² found that pneumatic compression plus subcutaneous heparin conferred a statistically significant reduction in the rate of VTE without a significant increase in bleeding versus mechanical prophylaxis alone after 173 operations, which involved 120 patients at high risk for VTE. Furthermore, Pannucci et al¹⁸ found that in high-risk plastic surgery patients, postoperative enoxaparin prophylaxis is protective against 60-day VTE when controlling for baseline risk and length of stay. Hatef et al¹ illustrated that enoxaparin confers a significant advantage in preventing VTE in high-risk patients. Compared with LDUH, LMWH is easier to titrate because of its selective binding to factors XA and IIA, without binding other plasma proteins. Other advantages of LMWH include that it requires only once-daily dosing and has better bioavailability as a subcutaneous injection. Furthermore, LMWH has a long half-life and therefore has less chance of developing heparin-induced thrombocytopenia.⁹ There have been reports that LMWH has a dose-related effect on bleeding complications.²³ However, reports have shown that as long as dosing is below 3400 units, LMWH is as effective as LDUH in preventing VTE and has low bleeding complications.² With no common standard on reporting postoperative complications and VTE, it is difficult to compare different treatment regimens. Selection of an optimal VTE prophylaxis pathway may be discovered if there were common standards.

Appropriate timing of administration of the first dose of chemoprophylaxis is not clear. Studies have shown that administration of the first dose of chemoprophylaxis within 6 hours can significantly increase the risk of bleeding.²⁴ We found a significant difference in hematoma formation in patients receiving preoperative dalteparin, which led to a change of our practice of giving dalteparin only postoperatively. The average timing of the first dose after surgery varied because of daily ward practicalities, but still we achieved a low VTE prophylaxis prevalence overall.

Our hospital policy states that IVC filters should be used in patients with significant risk factors for DVT in preference to the use of intravenous preoperative heparin administration due to the significant risk of bleeding associated with this practice, which we observed in our early cohort. The single case of DVT in our cohort may have been prevented by the use of a preoperative IVC filter. However, there are risks with the insertion of these devices, which should be considered.^25,26 Several studies have reviewed the use of IVC filters in high-risk patients. Unfortunately, further prospective studies are required to examine individuals at high risk of DVT to fully understand which exact patients would benefit from IVC filters.

All of our patients wore GCS, as it is well documented in the literature that these decrease the incidence of DVT by passively applying constant pressure, which reduces the volume of blood that remains in the leg, decreasing vein distension and stasis.²⁷ Some reports have shown that they reduce plasminogen activator 1 levels and the release of tissue plasminogen activator.²⁸ Graduated compression stockings are highly effective, with reports showing a 60% reduction in DVT risk.²⁷ We apply GCS prior to surgery, which has shown to be beneficial because patients are most susceptible to venodilatation and venous stasis at induction and during surgery.²⁰ We also encourage patient mobilization from day 1 after surgery.

We propose that using risk stratification algorithms is a useful and effective method to prevent VTE. A particularly difficult scenario is the treatment of very high-risk patients taking warfarin because of previous DVTs or PEs. For these patients, our hospital policy states that warfarin be stopped and an IVC filter be fitted 1 week before surgery. Our standard postoperative regimen of 5000 units of subcutaneous dalteparin is then prescribed with removal of the filter a week later when the patient is mobile. When VTE prophylaxis is being considered prior to surgery, clinicians should follow the local hospital guidelines in conjunction and agreement with the surgical team's experience and evidence-based medicine.²⁹ The American College of Chest Physicians² published guidelines on the prevention of VTE for various surgical specialties, but it was not specifically applicable for plastic surgery patients. Therefore, Davison et al³⁰ in 2004 modified the Caprini model to make the VTE prophylaxis more suitable to plastic surgery patients.

This study was retrospective and therefore the rate of silent or nonclinical DVT remains unknown. A prospective study using ultrasonography at multiple postoperative time intervals to find the true incidence of VTE following body-contouring procedures after massive weight loss is needed.

CONCLUSION

It is clear that VTE remains controversial in surgery, with various governing bodies publishing recommendations for this preventable postoperative complication. With numerous studies highlighting that patients with massive weight loss are at greater risk of postoperative complications, documenting VTE risk following body-contouring surgery after massive weight loss is important. There is a need for larger prospective studies with appropriate controls to fully understand the risk of VTE following body-contouring surgery after massive weight loss.