Pulmonary embolism after abdominal flap breast reconstruction: prediction and prevention

Contributors to post-operative venous thromboembolism risk after breast cancer surgery: A systematic review and meta-analysis

INTRODUCTION

Venous thromboembolism (VTE) events are a preventable complication for patients undergoing surgery for breast cancer. However, there is a lack of consistency in the existing literature regarding the potential risk factors affecting these individuals.

METHODS

This study aimed to investigate the potential risk factors associated with an increased risk of VTE following surgery for breast cancer. Data on patient characteristics such as age, body mass index (BMI), existing comorbidities, smoking history, surgical interventions, duration of hospitalization, and post-operative complications were recorded and analyzed.

RESULTS

Thirty-one studies investigating the incidence of VTE following surgical interventions for breast cancer were included. This study included 22,155 female patients with a mean age of 50.8 ± 2.9 years. The weighted mean length of surgery and hospital stay were 382.1 ± 170.0 min and 4.5 ± 2.7 days, respectively. The patients were followed-up for a weighted mean duration of 13.8 ± 21.2 months. The total incidence of VTE events was 2.2% (n = 489). Meta-analysis showed that patients with post-operative VTE had a significantly higher mean age and BMI, as well as longer mean length of surgery (P < 0.05). Comparing the techniques of autologous breast reconstruction showed that the risk of post-operative VTE is significantly higher with deep inferior epigastric perforator (DIEP) flaps, compared with the transverse rectus abdominus myocutaneous and latissimus dorsi myocutaneous flaps (P < 0.05). Compared with delayed reconstruction, immediate reconstruction was associated with a significantly higher incidence of VTE (P < 0.05). Smoking history, length of hospital stay, and Caprini score did not correlate with increased incidence of post-operative VTE.

CONCLUSION

The incidence rate of VTE events in patients receiving surgical treatment for breast cancer is 2.2%. Risk factors for developing post-operative VTE in this patient population were found to be older age, increased BMI, extended length of surgical procedures, and DIEP flap reconstruction.

An Effective Protocol for Perioperative Venous Thromboembolism Prophylaxis in DIEP Flap Breast Reconstruction: A Single Institution Retrospective Review

Background

Deep inferior epigastric artery perforator (DIEP) free flap breast reconstruction is one of the most highly used procedures for autologous breast reconstruction. Many venous thromboembolism (VTE) risk assessment models have been proposed in breast reconstructive surgery, including the widely used Caprini score. However, a paucity of data suggests an effective standardized VTE protocol. The purpose of this study was to determine the rate of VTE in our DIEP flap patients who were treated with this protocol.

Methods

A retrospective single-center review of DIEP flap breast reconstruction from 2016 to 2021 was performed. Data were collected on 554 patients and 893 flaps including demographics, intraoperative and perioperative details, and postoperative course. Patients who were not treated with our standard protocol were excluded. Data were analyzed with alpha = 0.05.

Results

The average age was 50.4 ± 9.9 years, and the total follow-up time was 16.9 ± 12.6 months. The average body mass index for the cohort was 30.1 ± 5.2. During the 90 postoperative days, the mean length of hospital stay was 4.3 days. There were six cases of postoperative VTE: five patients presented with pulmonary embolism (0.9%) and one patient (0.2%) had deep venous thrombosis with an overall VTE prevalence of 1.1%. No specific single factor could be attributed to VTE occurrence.

Conclusions

Using our standardized VTE prophylaxis protocol, our institution was effective at keeping VTE rates low. Additional studies would be beneficial to determine optimal VTE prophylaxis protocols in higher-risk patients, such as those with known clotting disorders.

Intra-abdominal pressure increases peri-operatively in patients undergoing deep inferior epigastric perforator flap reconstruction: A prospective study linking high intra-abdominal pressure to non-fatal lung embolism within one patient

BACKGROUND

The deep inferior epigastric perforator (DIEP) flap is the gold standard for autologous breast reconstruction. The procedure and peri-operative period are associated with the risk of severe post-operative complications, like venous thromboembolic events (VTE) and lung embolism. Whether the intra-abdominal pressure (IAP) increases after the closure of the abdominal defect, thereby potentially affecting the venous backflow and the risk of VTE, is currently not known.

AIM

The primary aim is to test if the closure of the abdominal donor site increases the IAP in women undergoing secondary DIEP flap breast reconstruction.

MATERIALS AND METHOD

By using a Unometer, we measured the intravesical pressure as a surrogate marker for the IAP, at baseline, immediately after, and 24 h after abdominal skin closure, for 13 patients.

RESULTS

The mean IAP increased from 6.1 mmHg (95% CI 4.6-7.7) at baseline to 9.0 mmHg (95% CI 8.0-10.0) immediately after skin closure [mean diff. 2.9 (95% CI 1.0-4.8) (p = 0.007)] and further up to 11.7 mmHg (95% CI 9.0-14.5) 24 h after closure [mean diff. 5.3 (95% CI 1.4-9.1) (p = 0.012)]. We found that IAP varies among the patients, regardless of the tightness of abdominal closure or rectus plication (n = 3). Immediately after closure, none of the isolated patients showed abnormal levels of IAP (>12 mmHg), while eight out of 12 isolated patients (67%) showed IAP levels above the normal range after 24 h. One patient developed a non-fatal lung embolism.

CONCLUSION

The mean IAP increases significantly over the post-operative period after DIEP flap reconstruction, although abnormal IAP values are only seen 24 h after the closure of the skin.

Incidence of Venous Thromboembolism Based on Caprini Score in Deep Inferior Epigastric Perforator Flap Breast Reconstruction

BACKGROUND

 Deep inferior epigastric perforator (DIEP) flaps are commonly used for autologous breast reconstruction, but reported rates of venous thromboembolism (VTE) are up to 6.8%. This study aimed to determine the incidence of VTE based on preoperative Caprini score following DIEP breast reconstruction.

METHODS

 This retrospective study included patients who underwent DIEP flaps for breast reconstruction between January 1, 2016 and December 31, 2020 at a tertiary-level, academic institution. Demographics, operative characteristics, and VTE events were recorded. Receiver operating characteristic analysis was performed to determine the area under the curve (AUC) of the Caprini score for VTE. Univariate and multivariate analyses assessed risk factors associated with VTE.

RESULTS

 This study included 524 patients (mean age 51.2 ± 9.6 years). There were 123 (23.5%) patients with the Caprini score of 0 to 4, 366 (69.8%) with scores 5 to 6, 27 (5.2%) with scores 7 to 8, and 8 (1.5%) patients with scores >8. Postoperative VTE occurred in 11 (2.1%) patients, at a median time of 9 days (range 1-30) after surgery. VTE incidence by the Caprini score was 1.9% for scores 3 to 4, 0.8% for scores 5 to 6, 3.3% for scores 7 to 8, and 13% for scores >8. The Caprini score achieved an AUC of 0.70. A Caprini score >8 was significantly predictive of VTE on multivariable analysis relative to scores 5 to 6 (odds ratio = 43.41, 95% confidence interval = 7.46-252.76, p < 0.001).

CONCLUSION

 In patients undergoing DIEP breast reconstruction, VTE incidence was highest (13%) in Caprini scores greater than eight despite chemoprophylaxis. Future studies are needed to assess the role of extended chemoprophylaxis in patients with high Caprini scores.

Venous thromboembolism incidence in postoperative breast cancer patients

BACKGROUND

Venous Thromboembolism (VTE) is an important cause of morbidity in cancer patients. Breast cancer patients undergoing surgical treatment are at an increased risk of VTE. The aim of this study was to determine the frequency of VTE in patients who underwent surgery for the treatment of breast cancer and to identify the related risk factors.

METHODS

A historical cohort of patients at the São Paulo State Cancer Institute (ICESP) underwent surgery for breast cancer. The inclusion criteria covered patients with invasive breast cancer or ductal carcinoma in situ who had breast surgery anytime from January 2016 to December 2018.

RESULTS

Of the 1672 patients included in the study, 15 had a confirmed diagnosis of VTE (0.9%), and 3 of these had deep vein thrombosis (0.2%), and 12, had pulmonary thromboembolism (0.7%). Clinical and tumoral characteristics did not differ between the groups. The incidence of VTE was higher in patients who had undergone skin-sparing mastectomy or nipple-sparing mastectomy (p = 0.032). Immediate reconstruction, particularly with abdominal-based flaps (4.7%), increased VTE events (p = 0.033). Median surgical time was higher in patients with VTE episodes (p = 0.027), and total hospital length of stay increased in days (6 days vs. 2 days, p = 0.001). Neoadjuvant chemotherapy and postoperative prophylaxis with Low Molecular Weight Heparin (LMWH) were associated with lower VTE rates (0.2% vs. 1.2%, p = 0.048 and 0.7% vs. 2.7%, p = 0.039; respectively) in these patients.

CONCLUSIONS

The incidence of VTE events in breast cancer patients who underwent surgery was 0.9%. Immediate reconstruction (especially with abdominal-based flaps), skin-sparing/nipple-sparing mastectomies, and longer surgeries were associated with increased risk. The LMWH postoperative prophylaxis reduced this risk.

Venous Thromboembolism Rates After Free Flap Reconstruction of the Head and Neck Region

BACKGROUND

Venous thromboembolism (VTE) is a major concern for the postoperative hospitalized patient, especially after long and complex procedures. Cancer itself also contributes to the hypercoagulable state, further complicating the management of patients. Despite prophylaxis, breakthrough events can occur. We aimed to assess our institutional VTE and bleeding rates after free flap reconstruction of the head and neck (H&N) region and the factors associated with VTE events.

METHODS

A retrospective review of the patients who underwent H&N free flap reconstruction at an academic center from 2012 to 2021 was performed from a prospectively maintained database. Data regarding patient demographics, medical history, surgical details, and overall outcomes were collected. Outcomes studied included postoperative 30-day VTE rates and major bleeding events. Patients who had a VTE event were compared with the rest of the cohort to identify factors associated with VTE.

RESULTS

Free flap reconstruction of the H&N region was performed in 949 patients. Reconstruction after cancer extirpation for squamous cell carcinoma was the most common etiology (79%). The most common flap was thigh based (50%), followed by the fibula (29%). The most common postoperative VTE chemoprophylaxis regimen was enoxaparin 30 mg twice daily (83%). The VTE and bleeding rates over the 10-year period were 4.6% (n = 44) and 8.7% (n = 83), respectively. Body mass index (28.7 ± 5.8 vs 26.2 ± 6.6, P = 0.013) and pulmonary comorbidities were found to be significantly higher in patients who had a VTE event (43% vs 27%, P = 0.017). Patients with a VTE event had a prolonged hospital stay of 8 more days (19.2 ± 17.4 vs 11 ± 7, P = 0.003) and a higher incidence of bleeding events (27% vs 8%, P < 0.001).

CONCLUSIONS

Postoperative VTE is a significant complication associated with increased length of hospitalization in patients undergoing free flap reconstruction of the H&N region. Institutional measures should be implemented on an individualized basis based on patient comorbidities to improve the postoperative VTE rates, while balancing the bleeding events.

Chemoprophylaxis and Management of Venous Thromboembolism in Microvascular Surgery

This review aims to highlight the common pharmacological and nonpharmacological interventions utilized for thromboprophylaxis as well as flap salvage in microsurgery. A literature review was conducted in PubMed/National Center for Biotechnology Information, Scopus, Web of Science, and MEDLINE databases. Articles with a focus on thromboprophylaxis in microsurgical procedures spanning head and neck surgery, breast and extremity microvascular reconstruction, deep venous thrombosis/pulmonary embolus in microvascular surgery, and flap thrombosis and salvage were included in this review. The majority of available evidence supports mechanical venous thromboembolism (VTE) prophylaxis in all patients undergoing microsurgery given the presence of multiple risk factors for VTE within this particular patient population. Based on the literature review, addition of VTE chemoprophylactic agents is beneficial and an algorithmic approach to thromboprophylaxis in microsurgery patients and management of patients with thrombosis based on literature review and senior authors' experience is recommended and outlined.

A UK consensus statement on thromboprophylaxis for autologous breast reconstruction ,

Microsurgical breast reconstruction accounts for 22% of breast reconstructions in the UK. Despite thromboprophylaxis, venous thromboembolism (VTE) occurs in up to 4% of cases. Using a Delphi process, this study established a UK consensus on VTE prophylaxis strategy, for patients undergoing autologous breast reconstruction using free-tissue transfer. It captured geographically divergent views, producing a guide that reflected the peer opinion and current evidence base.

METHODS

Consensus was ascertained using a structured Delphi process. A specialist from each of the UK's 12 regions was invited to the expert panel. Commitment to three to four rounds of questions was sought at enrollment. Surveys were distributed electronically. An initial qualitative free-text survey was distributed to identify likely lines of consensus and dissensus. Each panelist was provided with full-text versions of key papers on the topic. Initial free-text responses were analyzed to develop a set of structured quantitative statements, which were refined via a second survey as a consensus was approached.

RESULTS

The panel comprised 18 specialists: plastic surgeons and thrombosis experts from across the UK. Each specialist completed three rounds of surveys. Together, these plastic surgeons reported having performed more than 570 microsurgical breast reconstructions in the UK in 2019. A consensus was reached on 27 statements, detailing the assessment and delivery of VTE prophylaxis.

CONCLUSION

To our knowledge, this is the first study to collate current practice, expert opinion from across the UK, and a literature review. The output was a practical guide for VTE prophylaxis for microsurgical breast reconstruction in any UK microsurgical breast reconstruction unit.

An Ounce of Prediction is Worth a Pound of Cure: Risk Calculators in Breast Reconstruction

Preoperative risk calculators provide individualized risk assessment and stratification for surgical patients. Recently, several general surgery–derived models have been applied to the plastic surgery patient population, and several plastic surgery–specific calculators have been developed. In this scoping review, the authors aimed to identify and critically appraise risk calculators implemented in postmastectomy breast reconstruction.

Prolonged Venous Thromboembolism Prophylaxis May Not Be Necessary for DIEP Flap Breast Reconstruction: A Tertiary Center's 10-Year Experience

BACKGROUND

 Based on the 2005 Caprini Risk Assessment Model for venous thromboembolism, the American Society of Plastic Surgeons prevention guidelines would result in prolonged chemoprophylaxis (1 week or more) for the majority of patients undergoing deep inferior epigastric perforator flap breast reconstruction. We aim to assess the necessity of prolonged prophylaxis by describing our institutional experience in thromboembolism prevention and evaluating the incidence of symptomatic VTE in our patient cohort.

METHODS

 Women who underwent DIEP flap reconstruction from August 2011 to March 2020 at a tertiary care center were included. Charts were retrospectively reviewed for patient characteristics, VTE prophylaxis regimens, and development of deep vein thrombosis and pulmonary embolism within 60 days of surgery. Caprini scores were calculated for all patients.

RESULTS

 Out of the 249 patients included in the study, 245 patients received chemoprophylaxis only during hospitalization, while four patients additionally received anticoagulant for at least 2 weeks after discharge for prophylactic or therapeutic indications. The cohort's average Caprini score was 6.0, with 72.7% of scores between 3 and 6 and 26.5% at 7 or higher. One patient (0.4%), who scored a 7 and received prophylaxis only while hospitalized, developed deep vein thrombosis. There were no cases of pulmonary embolism. There was no significant difference in VTE rate between patients who received chemoprophylaxis consistent with ASPS guidelines and those who did not (p = 1.000).

CONCLUSION

 Despite our limited chemoprophylaxis use in DIEP flap patients, our VTE incidence is low. This current work suggests that the blanket application of prolonged prophylaxis is not warranted, and it further serves as impetus to re-evaluate the 2005 Caprini RAM in this patient population.

Safety of a Modified Lipoabdominoplasty Technique for Donor-Site Closure in Abdominal-Based Free Flap Breast Reconstruction

BACKGROUND

The aesthetic and functional outcomes of the donor site following abdominal-based free flap breast reconstruction have been suboptimal. The objective of this study is to evaluate a modified liposuction-assisted abdominoplasty technique combined with rectus plication (LPARSP) adopted from cosmetic abdominoplasty practice.

PATIENTS AND METHODS

All abdominal-based free flap breast reconstructions from 01/2017 to 03/2019 were reviewed. Patients with central fullness and sufficient tissue surplus on the abdomen, thighs and flanks who received LPARSP and rectus plication were identified (LPARSP group) and matched for age and body mass index with patients who underwent conventional abdominoplasty (CA group). Abdominal skin sensation, objective functional and aesthetic measures of the abdomen, as well as patient-reported outcomes (Breast-Q), were analyzed.

RESULTS

A total of 28 patients were included. Groups were similar in demographics. The mean amount of lipoaspirate in the LPARSP group was 1054±613.5 ml. The postoperative course was similar in both groups. The LPARSP technique resulted in a lower positioned horizontal scar (p = 0.03). The aesthetic outcome was superior in the LPARSP group (p < 0.0001). Furthermore, the LPARSP group presented with a decreased bulging rate (p = 0.05), and secondary refinement procedures were less frequently demanded (p = 0.02). In addition, the abdominal wall sensation of the flanks was improved in the LPARSP group (p = 0.05), whereby patient-reported outcome measures did not differ between groups.

CONCLUSIONS

Lipoabdominoplasty with rectus plication represents a safe approach for donor-site closure in selected patients undergoing abdominal-based free flap breast reconstruction. Superior functional and aesthetic results paired with improved abdominal wall sensation are achieved compared to CA.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Clinical course of venous thromboembolism following abdominally based microsurgical breast reconstruction: A case series

BACKGROUND

Venous thromboembolism (VTE) is a potentially devastating complication following abdominally based microsurgical breast reconstruction, with a reported incidence of 0.08-4%. The authors aim to describe disease presentation and clinical course following VTE diagnosis in patients within their practice.

METHODS

A retrospective chart review identified patients who underwent microsurgical breast reconstruction from January 2007 through December 2018. Patients with VTE diagnosed within 90 days of surgery were included. Demographics, co-morbidities, signs and symptoms, and characteristics of oncologic, surgical, and post-operative care were analyzed.

RESULTS

Seven hundred one patients underwent microsurgical breast reconstruction. Eleven patients with pulmonary embolism (PE) and four with deep vein thrombosis (DVT) were identified, resulting in VTE incidence of 2.1% (0.57% DVT, 1.6% PE). Patients were on average 51 years old and had an average body mass index (BMI) of 31.7 kg/m2. Two had a history of VTE, and none had a known hypercoagulable disorder. Using the 2005 Caprini model, all were high risk and seven were highest risk. Among those with PE, the most common symptom was shortness of breath, and the most common signs were desaturation or supplemental oxygen requirements. VTE was diagnosed on average 14.2 days post-operatively (range 2-52 days).

CONCLUSION

VTE is an infrequent complication following abdominally based microsurgical breast reconstruction. We recommend a high index of suspicion in women reporting shortness of breath or having desaturation, especially in those with high BMI, high Caprini scores, post-operative complications, or early return to the operating room.

A Systematic Review and Meta-Analysis of Microvascular Stacked and Conjoined-Flap Breast Reconstruction

BACKGROUND

 Stacked and conjoined (SC) flaps are a useful means of increasing flap volume in autologous breast reconstruction. The majority of studies, however, have been limited to smaller, single-center series.

METHODS

 A systematic literature review was performed to identify outcomes-based studies on microvascular SC-flap breast reconstruction. Pooled rates of flap and operative characteristics were analyzed. Meta-analytic effect size estimates were calculated for reconstructive complication rates and outcomes of studies comparing SC flaps to non-SC flaps. Meta-regression analysis identified risk factors for flap complications.

RESULTS

 Twenty-six studies were included for analysis (21 case series, five retrospective cohort studies) for a total of 869 patients, 1,003 breasts, and 2006 flaps. The majority of flaps were harvested from the bilateral abdomen (78%, 782 breasts) followed by combined abdomen-thigh stacked flaps (22.2%, 128 breasts). About 51.1% of flaps were anastomosed to anterograde/retrograde internal mammary vessels (230 breasts) and 41.8% used internal mammary/intraflap anastomoses (188 breasts). Meta-analysis revealed a rate of any flap complication of 2.3% (95% confidence interval: 1.4-3.3%), Q-statistic value p = 0.012 (I ² = 43.3%). SC flaps had a decreased risk of fat necrosis compared with non-SC flaps (odds ratio = 0.126, p < 0.0001, I ² = 0.00%), though rates of any flap and donor-site complication were similar. Age, body mass index, flap weight, and flap donor site and recipient vessels were not associated with increased risk of any flap complication.

CONCLUSION

 A global appraisal of the current evidence demonstrated the safety of SC-flap breast reconstruction with low complication rates, regardless of donor site, and lower rates of fat necrosis compared with non-SC flaps.

Venous Thromboembolism following Microsurgical Breast Reconstruction: A Longitudinal Analysis of 12,778 Patients

BACKGROUND

Venous thromboembolism is a dreaded complication following microsurgical breast reconstruction. Although the high-risk nature of the procedure is well known, a thorough analysis of modifiable risk factors has not been performed. The purpose of this study was to analyze the association of such factors with the postoperative occurrence of venous thromboembolism longitudinally.

METHODS

Using the Truven MarketScan Database, a retrospective cohort study of women who underwent microsurgical breast reconstruction from 2007 to 2015 and who developed postoperative venous thromboembolism within 90 days of reconstruction was performed. Predictor variables included age, timing of reconstruction, body mass index, history of radiation therapy, history of venous thromboembolism, Elixhauser Comorbidity Index, and length of stay. Univariate analyses were performed, in addition to logistic and zero-inflated Poisson regressions, to evaluate predictors of venous thromboembolism and changes in venous thromboembolism over the study period, respectively.

RESULTS

Twelve thousand seven hundred seventy-eight women were identified, of which 167 (1.3 percent) developed venous thromboembolism. The majority of venous thromboembolisms (67.1 percent) occurred following discharge, with no significant change from 2007 to 2015. Significant predictors of venous thromboembolism included Elixhauser score (p < 0.01), history of venous thromboembolism (p < 0.03), and length of stay (p < 0.001). Compared to patients who developed a venous thromboembolism during the inpatient stay, patients who developed a postdischarge venous thromboembolism had a lower mean Elixhauser score (p < 0.001).

CONCLUSIONS

Postoperative venous thromboembolism continues to be an inadequately addressed problem, as evidenced by a stable incidence over the study period. Identification of modifiable risk factors, such as length of stay, provides potential avenues for intervention. As the majority of venous thromboembolisms occur following discharge, future studies are warranted to investigate the role for an intervention in this period.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, III.

Breast Reconstruction with Free Abdominal Flaps Is Associated with Persistent Lower Extremity Venous Stasis

BACKGROUND

Previous work has demonstrated the occurrence of lower extremity venous stasis in the early postoperative period after breast reconstruction with free abdominal flaps. The authors investigated whether venous stasis persisted through the day of discharge, thus potentially exposing patients to an elevated risk of venous thromboembolism following discharge.

METHODS

Patients who underwent breast reconstruction with free abdominal flaps were enrolled prospectively and underwent duplex ultrasound of the common femoral vein at the following time points: preoperatively, postoperative day 1, and day of discharge. Parameters of interest included common femoral vein diameter, area, and maximum flow velocity.

RESULTS

Thirty patients with a mean age of 50.3 years (range, 29 to 70 years) underwent breast reconstruction with 52 free abdominal flaps. A significant increase in common femoral vein diameter (19.1 percent; p < 0.01) and area (46.8 percent; p < 0.01) correlated with a significant reduction in maximum flow velocity (-10.9 percent; p = 0.03) between baseline and postoperative day 1. These changes persisted through the day of discharge [common femoral vein diameter, 17.8 percent (p < 0.01); area, 46 percent (p < 0.01); and maximum flow velocity, -11.3 percent (p = 0.01)]. Venous parameters were not influenced by unilateral versus bilateral flap harvest (p = 0.48).

CONCLUSIONS

Postoperative lower extremity venous stasis following autologous breast reconstruction with free abdominal flaps seems to persist through the day of discharge. This finding may explain why patients remain at risk for venous thromboembolism after discharge. Although the authors' findings are at odds with current venous thromboembolism prophylaxis recommendations, additional studies are indicated to examine whether these findings translate into venous thromboembolism events.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Free Tissue Breast Reconstruction

Free tissue transfer serves as a modern workhorse for breast reconstruction. Advancements in microsurgical technique have allowed for the development of free flap procedures that produce an aesthetic breast while minimizing donor site morbidity. Here, the authors review the use of different free flap procedures for breast reconstruction with a focus on the preferred and most commonly used flap, the deep inferior epigastric perforator flap. Each flap has its advantages and drawbacks, and certain patient risk factors increase postoperative complications. Other techniques of breast reconstruction including pedicled flaps and adjunctive fat grafting are also briefly discussed.

Untapped potential of multicenter studies: a review of cardiovascular risk prediction models revealed inappropriate analyses and wide variation in reporting

BACKGROUND

Clinical prediction models are often constructed using multicenter databases. Such a data structure poses additional challenges for statistical analysis (clustered data) but offers opportunities for model generalizability to a broad range of centers. The purpose of this study was to describe properties, analysis, and reporting of multicenter studies in the Tufts PACE Clinical Prediction Model Registry and to illustrate consequences of common design and analyses choices.

METHODS

Fifty randomly selected studies that are included in the Tufts registry as multicenter and published after 2000 underwent full-text screening. Simulated examples illustrate some key concepts relevant to multicenter prediction research.

RESULTS

Multicenter studies differed widely in the number of participating centers (range 2 to 5473). Thirty-nine of 50 studies ignored the multicenter nature of data in the statistical analysis. In the others, clustering was resolved by developing the model on only one center, using mixed effects or stratified regression, or by using center-level characteristics as predictors. Twenty-three of 50 studies did not describe the clinical settings or type of centers from which data was obtained. Four of 50 studies discussed neither generalizability nor external validity of the developed model.

CONCLUSIONS

Regression methods and validation strategies tailored to multicenter studies are underutilized. Reporting on generalizability and potential external validity of the model lacks transparency. Hence, multicenter prediction research has untapped potential.

REGISTRATION

This review was not registered.

The Timing of Chemoprophylaxis in Autologous Microsurgical Breast Reconstruction

BACKGROUND

Patients undergoing autologous breast reconstruction are at high risk of perioperative venous thromboembolic events. The efficacy of chemoprophylaxis in decreasing venous thromboembolic events is well established, but the timing of chemoprophylaxis remains controversial. The authors compare the incidence of bleeding following preoperative versus postoperative initiation of chemoprophylaxis in microvascular breast reconstruction.

METHODS

A retrospective chart review was performed from August of 2010 to July of 2016. Initiation of chemoprophylaxis changed from postoperative to preoperative in 2013, dividing subjects into two groups. Patient demographics, comorbidities, and complications were reviewed.

RESULTS

A total of 196 patients (311 flaps) were included in the study. A total of 105 patients (166 flaps) received preoperative enoxaparin (40 mg) and 91 patients (145 flaps) received postoperative chemoprophylaxis. A total of five patients required hematoma evacuation (2.6 percent). Of these, one hematoma (1 percent) occurred in the preoperative chemoprophylaxis group. Seven patients received blood transfusions: three in the preoperative group and four in the postoperative group (2.9 percent versus 4.4 percent; p = 0.419). There was a total of one flap failure, and there were no documented venous thromboembolic events in any of the groups.

CONCLUSIONS

This study demonstrates that preoperative chemoprophylaxis can be used safely in patients undergoing microvascular breast reconstruction. The higher rate of bleeding in the postoperative group may be related to the onset of action of enoxaparin of 4 to 6 hours, which allows for intraoperative hemostasis in the preoperative group and possibly potentiating postoperative oozing when administered postoperatively.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Implementation of a Venous Thromboembolism Prophylaxis Protocol Using the Caprini Risk Assessment Model in Patients Undergoing Mastectomy

BACKGROUND

Guidelines for venous thromboembolism (VTE) prophylaxis are not well-established for breast surgery patients. An individualized VTE prophylaxis protocol using the Caprini score was adopted at our institution for patients undergoing mastectomy ± implant-based reconstruction. In this study, we report our experience during the first year of implementation.

METHODS

In August 2016, we adopted a VTE prophylaxis protocol for patients undergoing mastectomy ± implant-based reconstruction. We used the Caprini score, a validated risk assessment tool for VTE, to determine each patient's perioperative prophylaxis regimen. Detailed chart review was performed to record patient and treatment details, the Caprini score, pharmacologic VTE prophylaxis administration, and 30-day incidence of VTE and bleeding complications. We performed univariate analysis to identify factors associated with protocol compliance.

RESULTS

Overall, 522 patients met the inclusion criteria. Median age was 51 years, 486 (93.1%) patients had malignancy, 234 (44.8%) underwent bilateral mastectomy, and 350 (67.0%) underwent reconstruction. Caprini scores ranged from 2 to 11, with 431 (82.6%) patients having a score from 5 to 7. Overall protocol compliance was 60.5%, and was associated with bilateral mastectomy (p = 0.02), reconstruction (p = 0.03), and longer procedures (p < 0.001). The rate of VTE was 0.2% (95% confidence interval [CI] 0.03-1.1%), rate of reoperation for hematoma was 2.7% (95% CI 1.6-4.5%), and rate of blood transfusion was 0.4% (95% CI 0.1-1.4%).

CONCLUSIONS

The implementation of an individualized VTE prophylaxis protocol for patients undergoing mastectomy ± implant-based reconstruction is safe and feasible. Despite a high-risk cohort, the incidence of VTE was very low and bleeding complications were consistent with reported rates for breast surgery. Continued evaluation of this strategy is warranted.

Justification of routine venous thromboembolism prophylaxis in head and neck cancer reconstructive surgery

BACKGROUND

Venous thromboembolism (VTE) is a preventable complication in which early ambulation is expected after head and neck surgery. Thus, the role of VTE prophylaxis is questionable and needs further assessment. The purpose of this study was to specify the relative contributing risk factors for patients who underwent head and neck cancer ablation with immediate reconstruction.

METHODS

A retrospective analysis was conducted of consecutive head and neck cancer ablations with immediate reconstructions between 2008 and 2013. Dextran and prostaglandin E2 (PGE2) were routinely given as flap thromboprophylaxis. Logistic regression was applied to analyze the potentially significant risk factors.

RESULTS

Of 1953 subjects, the incidence of symptomatic VTE was 2.2% with 0.1% mortality rate. Prolonged surgery (>592.5 minutes; P = .048), immobilization (>4 days; P = .019), and subjects without postoperative flap thromboprophylaxis (P = .002) are significant risk factors for VTE development.

CONCLUSION

Our flap thromboprophylaxis regime might have played a crucial role in keeping the incidence of VTE low. Despite prolonged immobilization in fibula flap reconstruction, the incidence of VTE remained low when flap thromboprophylaxis was given.

[Benefit of simultaneous contralateral breast symmetry procedure with unilateral breast reconstruction using DIEP flaps. About 33 cases]

BACKGROUND

After unilateral breast reconstruction, a procedure on the contralateral breast is often needed to achieve symmetry. Here, we present a single surgeon's experience with performing contralateral symmetry procedures simultaneously with DIEP flap.

METHODS

We evaluated 33 consecutive patients (mean age, 52.1 years) who underwent DIEP flap unilateral breast reconstruction and a simultaneous contralateral breast procedure performed and 2 patients with delayed controlateral symmetry procedures. A single-stage breast cancer reconstruction is successful if after the original reconstruction no correction for revision of breast mound, or contralateral breast procedures are performed, under general anesthetic, to complete the reconstruction.

RESULTS

In 24 patients (73%), breast reconstruction was completed after a single stage with one general anesthetic, and in 8 patients (24%), revisions were performed with two general anesthetic (7 patients) and three general anesthetic in one case. Reconstructions requiring more than one general anesthetic were due to 4 of 39 (10%) postoperative complications. Mean operating time was 485 minutes.

CONCLUSIONS

For patients who need contralateral reduction mammoplasty or mastopexy for symmetry, performing these procedures and breast reconstruction simultaneously facilitates single-stage breast reconstruction in most patients.

Method of Breast Reconstruction Determines Venous Thromboembolism Risk Better Than Current Prediction Models

Background:

Venous thromboembolism (VTE) risk models including the Davison risk score and the 2005 Caprini risk assessment model have been validated in plastic surgery patients. However, their utility and predictive value in breast reconstruction has not been well described. We sought to determine the utility of current VTE risk models in this population and the VTE rate observed in various methods of breast reconstruction.

Methods:

A retrospective review of breast reconstructions by a single surgeon was performed. One hundred consecutive transverse rectus abdominis myocutaneous (TRAM) patients, 100 consecutive implant patients, and 100 consecutive latissimus dorsi patients were identified over a 10-year period. Patient demographics and presence of symptomatic VTE were collected. 2005 Caprini risk scores and Davison risk scores were calculated for each patient.

Results:

The TRAM reconstruction group was found to have a higher VTE rate (6%) than the implant (0%) and latissimus (0%) reconstruction groups (P < 0.01). Mean Davison risk scores and 2005 Caprini scores were similar across all reconstruction groups (P > 0.1). The vast majority of patients were stratified as high risk (87.3%) by the VTE risk models. However, only TRAM reconstruction patients demonstrated significant VTE risk.

Conclusions:

TRAM reconstruction appears to have a significantly higher risk of VTE than both implant and latissimus reconstruction. Current risk models do not effectively stratify breast reconstruction patients at risk for VTE. The method of breast reconstruction appears to have a significant role in patients’ VTE risk.