Microsurgery and the Hypercoagulable State: A Hematologist's Perspective

[Perioperative Assessment and Management of Hypercoagulability and Thrombophilia in Microsurgery: Consensus Report of the German-Speaking Society for Reconstructive Microsurgery (GSRM)]

Uninterrupted blood flow through microsurgically anastomosed vessels is crucial for the postoperative success of reconstructive microsurgery. Contrary to the highly standardized anastomosis techniques, the pivotal partner discipline of evidence-based microsurgical haemostaseology and haemorrheology is still in its infancy. Prospective clinical studies yielding evidence-based recommendations are notably lacking. Currently, perioperative management in microsurgery is based solely on site-specific empirical experience. The collective aim of these diverse efforts is the preoperative identification of increased coagulation (hypercoagulability) or clotting activities (thrombophilia) and the development of relevant anticoagulation strategies. During the 43rd Annual Meeting of the German-Speaking Working Group for Microsurgery (DAM) in November 2022 in Frankfurt, experts in microsurgery, haemostaseology, and anaesthesia deliberated on the fundamentals of coagulation and physiology. Also, alongside a literature review, consensus recommendations for the perioperative management of hypercoagulopathies were established. Subsequently, methodologies were assessed within the panel, criteria for decision-making were gathered, and, ultimately, a consensus recommendation by DAM regarding a perioperative algorithm was devised, which is detailed in this position paper.

Impact of COVID-19 on Thrombotic Complications in Microsurgery: Deep Inferior Epigastric Perforator Flap Outcomes Amid Pandemic

Background

Emerging research underscores the heightened risk of vasculitis and microvascular thrombosis in COVID-19 patients, alongside concerns about prothrombotic events post-severe acute respiratory syndrome coronavirus 2 vaccination. Following the pandemic's end, we sought a comprehensive analysis to elucidate its impact on microsurgical thrombosis rates, informed by empirical and anecdotal evidence.

Methods

An institutional review board-approved retrospective review analyzed autologous breast reconstruction cases in women from January 2019 to March 2022. Data on patient history, COVID-19 infection, vaccination status, and postoperative complications were collected. Patients were categorized as prepandemic and pandemic, and based on COVID-19 influence (infection or vaccination) for statistical evaluation.

Results

Among 527 patients, 216 underwent surgery prepandemic and 311 during the pandemic, revealing thrombotic event rates of 3.2% and 5.4%, respectively. Further comparative analysis showed no significant difference in thrombotic events among patients affected by COVID-19 through infection or vaccination during the pandemic.

Conclusions

Contrary to concerns, COVID-19 infection or vaccination status does not significantly increase thrombotic event rates in deep inferior epigastric perforator flap breast reconstructions. This study offers vital insights, affirming the safety and efficacy of microsurgical procedures amid the pandemic, thereby guiding microsurgeons in optimizing patient care in the post-COVID-19 era.

An Institutional Analysis of Early Postoperative Free Tissue Transfer Takeback Procedures

BACKGROUND

 Postoperative free tissue transfer reexploration procedures are relatively infrequent but associated with increased overall failure rates. This study examines the differences between flaps requiring takeback versus no takeback, as well as trends in reexploration techniques that may increase the odds of successful salvage.

METHODS

 A retrospective review was conducted on all free tissue transfers performed at our institution from 2011 to 2022. Patients who underwent flap reexploration within 30 days of the original procedure were compared with a randomly selected control group who underwent free flap procedures without reexploration (1:2 cases to controls). Univariate and multivariate logistic regression analyses were performed.

RESULTS

 From 1,213 free tissue transfers performed in the study period, 187 patients were included in the analysis. Of the total flaps performed, 62 (0.05%) required takeback, and 125 were randomly selected as a control group. Free flap indication, flap type, reconstruction location, and number of venous anastomoses differed significantly between the two groups. Among the reexplored flaps, 8 (4.3% of the total) had a subsequent failure while 54 (87.10%) were salvaged, with significant differences in cause of initial flap failure, affected vessel type, and salvage technique.

CONCLUSION

 Free tissue transfers least prone to reexploration involved breast reconstruction in patients without predisposition to hypercoagulability or reconstruction history. When takeback operations were required, salvage was more likely in those without microvascular compromise or with an isolated venous injury who required a single exploratory operation.

Venous Thromboembolism after DIEP Flap Breast Reconstruction: Review of Outcomes after a Postoperative Prophylaxis Protocol

BACKGROUND

Deep inferior epigastric perforator (DIEP) flap breast reconstruction is among the higher-risk patient groups for venous thromboembolism (VTE) in plastic surgery. Surgeons often opt for a patient-specific approach to postoperative anticoagulation, and the field has yet to come to a consensus on VTE chemoprophylaxis regimens.

METHODS

A new chemoprophylaxis protocol was introduced starting in March of 2019 that involved 2 weeks of treatment with enoxaparin, regardless of patient risk factors. A retrospective chart review was conducted on all patients who underwent DIEP flap breast reconstruction at the authors' institution between January of 2014 and March of 2020. Patients were grouped based on whether they enrolled in the new VTE protocol in the postoperative period or not. Patient demographics, prophylaxis type, and outcomes data were recorded, retrospectively. The primary outcome measure was postoperative VTE incidence.

RESULTS

Risk of VTE was significantly higher in patients discharged without VTE prophylaxis compared with patients discharged with prophylaxis (3.7% versus 0%; P = 0.03). Notably, zero patients in the VTE prophylaxis group developed a deep venous thrombosis or pulmonary embolism. In addition, the risk of a VTE event was 25 times greater in patients with a Caprini score greater than or equal to 6 ( P = 0.0002).

CONCLUSION

The authors demonstrate the successful implementation of a 2-week VTE chemoprophylaxis protocol in DIEP flap breast reconstruction patients that significantly reduces the rate of VTE while not affecting the rate of hematoma complications.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Staphylococcus Scalded Skin Syndrome-Induced Thrombosis Leading to Free Flap Complications: A Case Report and Review

Staphylococcal scalded skin syndrome (SSSS) is a clinical term used for a spectrum of blistering skin conditions induced by the epidermolytic toxins of the Staphylococcus aureus bacteria. The complications of SSSS include thrombosis; however, the pathophysiology of this is still poorly understood. We present a case of free anterolateral thigh (ALT) flap failure in a patient as a result of widespread flap thrombosis associated with staphylococcal scalded skin syndrome (SSSS). This is the first reported case of free flap failure associated with SSSS. Free flap failure due to acquired prothrombotic conditions, such as infection, is a rare and potentially under-reported phenomenon. This article aims to further explore the role of both thrombophilias and provoked thrombotic events in free flap failure. A review of the literature will also be presented, and cases of free flap failure in patients with infection-induced vascular complications will be summarised.

Use of Flow-through Free Flaps in Head and Neck Reconstruction

Background

Reconstructive obstacles in composite head and neck defects are compounded in reoperated, traumatized, irradiated, and vessel-depleted surgical fields. In cases that require multiple free flaps, recipient vessel accessibility and inset logistics become challenging. Strategic flow-through flap configurations mitigate these issues by supplying arterial inflow and venous outflow to a second flap in a contiguous fashion. This approach (1) permits the use of a singular native recipient vessel, (2) increases the reach of the vascular pedicle, avoiding the need for arteriovenous grafting, and (3) allows for a greater three-dimensional flexibility in configuring soft tissue and bony flap inset.

Methods

To demonstrate this technique, we conducted a retrospective review of all head and neck reconstruction patients presenting to us from March 2019 to April 2021.

Results

We present seven oncological and two traumatic patients (N = 9) who received flow-through free flaps for head and neck reconstruction. The most common flap used as the flow-through flap was the anterolateral thigh flap (N = 7), followed by the fibula flap (N = 2). Mean follow-up time was 507 days. No flap failures occurred.

Conclusion

In head and neck reconstruction, the use of the flow-through principle enables uninterrupted vascular flow for two distinct free flaps in single-stage reconstruction for patients with vessel-depleted, irradiated, and/or reoperated fields. We demonstrate that flow-through flaps in the head and neck may be used successfully for a variety of cases and flaps.

Successful microvascular surgery in patients with thrombophilia in head and neck surgery: a case series

BACKGROUND

In this case series, a perioperative anticoagulation protocol for microvascular head and neck surgery in patients with thrombophilia is presented. Microvascular free-flap surgery is a standard procedure in head and neck surgery with high success rates. Nevertheless, flap loss-which is most often caused by thrombosis-can occur and has far-reaching consequences, such as functional impairment, prolonged hospitalization, and increased costs. The risk of flap loss owing to thrombosis is significantly increased in patients with thrombophilia. Therefore, perioperative anticoagulation is mandatory. To date, no perioperative anticoagulation protocol exists for these high-risk patients.

CASE PRESENTATION

We present three exemplary male Caucasian patients aged 53-57 years with free flap loss owing to an underlying, hidden thrombophilia.

CONCLUSION

We present a modified anticoagulation protocol for microvascular surgery in these high-risk patients, enabling successful microsurgical reconstruction.

Microsurgical breast reconstruction and primary hypercoagulable disorders

BACKGROUND

Primary hypercoagulable disorders pose a significant challenge to microsurgeons and have traditionally been regarded as a relative contraindication to free tissue transfer. Since free flaps offer numerous advantages in breast reconstruction, there is an effort to expand the population to whom these operations can be safely offered. The purpose of this study is to describe our chemoprophylaxis regimen in cases of primary hypercoagulability, as well as to compare flap outcomes and complications between women with and without hypercoagulability.

PATIENTS AND METHODS

A single institution retrospective review identified 15 patients (25 flaps) with known primary hypercoagulability who underwent microsurgical breast reconstruction from 2010 through 2020. There were 785 patients (1268 flaps) without primary hypercoagulability who underwent microsurgical breast reconstruction, including 40 patients (73 flaps) with a history of venous thromboembolism (VTE), evaluated for comparison. Patient characteristics, thromboprophylaxis regimen, and surgical outcomes were collected. In carrying out this cohort study, we have adhered to Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines.

RESULTS

Fifteen patients with primary hypercoagulability were identified, including heterozygous factor V Leiden mutation (n = 12), protein S deficiency (n = 1), prothrombin mutation (n = 1), and primary antiphospholipid syndrome (n = 1). Thirteen of these (87%) were discharged with an extended LMWH course. There was no postoperative VTE or mortality in this cohort, and no significant difference in hematoma or transfusion compared with the control group (p = .31, p = .87, respectively). The flap loss rate was 4% in the hypercoagulable group compared with 0.92% in the control group (p = .15). The salvage for arterial or venous compromise in the hypercoagulable group was poor (0% vs. 52%, p = .3).

CONCLUSION

Microsurgical breast reconstruction in women with primary hypercoagulability disorders is feasible with acceptable risk of flap loss but poor salvage potential. Postoperative thromboprophylaxis with extended prophylactic LMWH in this population appears to be a safe regimen.

Circumferential Radical Debridement and Omental Free Flap in the Treatment of Severe Chronic Venous Ulcers

BACKGROUND

Chronic venous leg ulcers are a significant health care burden with a difficult and unreliable treatment. Free flaps may be needed for wound coverage in severe cases. Incomplete removal of dermatoliposclerosis (DLS) area and/or not addressing the underlying venous dysfunction may contribute to the reported modest long-term results.

METHODS

A series of 5 patients with severe chronic venous ulcers of the leg, resistant to conservative treatment and superficial venous surgery, were treated with radical, circumferential, subfascial resection of the DLS skin and coverage with omental free flaps. Delayed arteriovenous (AV) loops were used as recipients. All patients had previous superficial venous surgery and multiple skin grafts. Mean follow-up was 8 years (4-15 years).

RESULTS

One hundred percent of flaps survived completely. No major complications occurred. One patient developed ulceration of the flap at 2 years and healed with basic wound care. At a mean follow-up of 8 years, all patients were ulcer-free. One patient died 15 years after the surgery for unrelated causes.

CONCLUSIONS

Radical circumferential resection of DLS area in severe chronic venous leg ulcers and coverage with a free omental flap using staged AV loop provided durable coverage in a series of 5 patients. Complete resection of DLS area, addressing the underlying venous pathology, and draining the flap to a healthy competent vein graft (AV loop) may contribute to these favorable results.

Operative Efficiency in Deep Inferior Epigastric Perforator Flap Reconstruction: Key Concepts and Implementation

The deep inferior epigastric perforator flap has become one of the most popular approaches for autologous breast reconstruction after mastectomy. As much of health care has moved to a value-based approach, reducing complications, operative time, and length of stay in deep inferior flap reconstruction is becoming increasingly important. In this article, we discuss important preoperative, intraoperative, and postoperative considerations to maximize efficiency when performing autologous breast reconstruction and offer tips on how to handle certain challenges.

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.

Microsurgical Breast Reconstruction in Patients with Disorders of Hemostasis: Perioperative Risks and Management

BACKGROUND

Surgical and technological advances have resulted in the widespread adoption of microsurgical breast reconstruction. Many comorbidities that potentially might impair vasculature and wound healing are no longer considered contraindications for these procedures. However, some uncertainty still prevails regarding the perioperative management of patients with disorders of hemostasis.

METHODS

The authors combined a literature review with a retrospective chart review of patients with disorders of hemostasis who had undergone microsurgical breast reconstruction at the senior author's (J.F.) center between 2015 to 2020. Several disorders associated with thrombotic and/or hemorrhagic complications were identified, and a standardized risk assessment and management strategy was developed in cooperation with a hematologist.

RESULTS

Overall, 10 studies were identified comprising 29 patients who had a defined disorder of hemostasis and underwent microsurgical breast reconstruction. Seventeen microsurgical breast reconstructions were performed on 11 patients at the senior author's (J.F.) center. High factor VIII levels, heterozygous factor V Leiden, and heterozygous prothrombin mutation G20210A were the most common genetic or mixed genetic/acquired thrombophilic conditions. As expected, hereditary antithrombin, protein C, or protein S deficiencies were rare. Among hemorrhagic disorders, thrombocytopenia, platelet dysfunction, and von Willebrand disease or low von Willebrand factor levels were those factors most frequently associated with increased perioperative bleeding.

CONCLUSIONS

Patients should be screened for elevated risk of thrombosis or bleeding before undergoing microsurgical breast reconstruction, and positive screening should prompt a complete hematologic evaluation. Interdisciplinary management of these disorders with a hematologist is essential to minimize risks and to obtain optimal reconstructive results.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, IV.

The prognostic role of extended preoperative hypercoagulability work-up in high-risk microsurgical free flaps: a single-center retrospective case series of patients with heterozygotic factor V Leiden thrombophilia

INTRODUCTION

Hypercoagulability is associated with an increased risk of microvascular complications and free flap failures. The authors present their experience and approach to diagnosing and treating patients with heterozygotic factor V Leiden (hFVL) thrombophilia undergoing free flap reconstruction.

METHODS

Between November 2009 and June 2018, 23 free flap surgeries were performed in 15 hypercoagulable patients with hFVL. According to the timing of perioperative hypercoagulability work-up, they were grouped into flaps with established diagnoses prior to surgery (Group A) versus flaps with unknown diagnoses prior to surgery (Group B). Baseline characteristics and perioperative complications were compared between both groups, including revision surgeries due to microvascular thromboses, acute bleedings, hematomas, flap necroses, and reconstructive failures.

RESULTS

HFVL mutations had been confirmed preoperatively in 14 free flap surgeries (61%, Group A), whereas in 9 free flap surgeries (39%, Group B), mutations were only diagnosed postoperatively after the occurrence of microvascular thromboses had warranted extended hypercoagulability work-up. The overall rate of intraoperative flap thromboses was 9% (n = 2), whereas the overall rate of postoperative flap thromboses was 43% (n = 10). The corresponding salvage rates were 100% (n = 2/2) for intraoperative and 40% (n = 4/10) for postoperative pedicle thromboses. A total of five free flaps were lost (22%). Upon comparison, flaps with an unconfirmed diagnosis prior to surgery were at ten times higher risk for developing total necroses (flaps lost in Group B = 4/9 versus Group A = 1/14; OR: 10.4; 95% CI 1.0, 134.7; p = 0.03).

CONCLUSION

Meticulous preoperative work-up of patients with any history of hypercoagulability can help reduce free flap loss rates, thus improving surgical outcomes and increasing patient safety.

Autologous Mandible Reconstruction in a Hypercoagulable Patient following Multiple Failed Free Flaps

Coagulopathies affect 3% of free flap patients and are among the leading causes of free flap failure. This report describes the case of a head and neck cancer patient that experienced two remote free flap failures before successful autologous mandibular reconstruction. Following identification of an unrecognized thrombophilic state, a focused anticoagulation strategy was executed, including an intraoperative heparin drip, stringent postoperative maintenance of Factor Xa levels between 0.3 and 0.5 IU per mL, and transition to an outpatient enoxaparin regimen of 1 mg per kg twice daily for 1.5 months following surgery. Here, we demonstrate that free tissue transfer following multiple previous failed attempts in the setting of hypercoagulability remains a viable reconstructive option with close interdisciplinary collaboration, close clinical monitoring, and patient-specific antithrombotic protocols.

The Role of von Willebrand Factor in Microvascular Surgery in Severely Injured Patients

Microvascular anastomosis has become a standard surgical technique for reconstruction because of increasing possibilities, indications, and clinical success regarding the survival of the flaps. However, the main dreaded complications exist in thrombosis. Leaving surgical complications aside, systemic problems like disorder of the coagulation-fibrinolysis system are a significant cause of graft loss usually being unrecognized. Reports exist describing a hypercoagulable state with clotting activation and inhibition of fibrinolysis after trauma and delayed surgery considering the secondary homeostasis. In this clinical case, a patient had a large soft tissue defect at the temporal side of the head after severe trauma. After some days of primary stabilization, reconstruction using a free microvascular latissimus dorsi flap was performed. Multiple revisions of the arterial and venous branches had to be performed intraoperatively due to insufficient flap perfusion. After 24 hours, definitive flap loss occurred due to multiple thrombosis in the arterial and venous branches. Postoperative comprehensive coagulation analysis revealed a distinct activation of primary hemostasis with massively increased von Willebrand factor parameters and factor VIII activity as well as acetylsalicylic acid resistance contributing to thrombotic occlusion. In severely injured patients, comprehensive preoperative determination of the coagulation status (especially those of the primary hemostasis) is indispensable before performing free flap reconstruction surgeries to reduce the risk of microvascular flap loss.

Utility of Viscoelastic Tests to Predict Flap Thrombosis: A Systematic Review

Background:

Flap thrombosis is a rare but devastating complication in microsurgery. Preoperative identification of patients at increased risk for microvascular thrombosis remains challenging. Viscoelastic testing (VET) provides a comprehensive evaluation of the clotting process and can effectively identify hypercoagulability. However, the utility of VET in microvascular reconstruction remains unclear.

Methods:

A systematic review of the association between VET and pedicle thrombosis and free flap loss was performed in accordance with Preferred Reporting Items for Systematic Reviews (PRISMA) guidelines. Identified studies were reviewed independently by two authors for pertinent data.

Results:

Six studies met inclusion criteria. Heterogenous study design and outcome reporting complicated direct comparisons and precluded a formal meta-analysis. Four studies found a statistically significant relationship between VET results and flap thrombosis or flap loss. The maximum clot strength and the fibrinogen-to-platelet ratio (FPR) were key viscoelastic parameters in these studies, both representing a measure of maximal clot strength. Specifically, an elevated FPR (>42%) generated a sensitivity and specificity for flap loss ranging from 57% to 75% and 60% to 82%, respectively. Notably, the negative predictive value for flap failure with a normal preoperative FPR was greater than 90% in all studies reporting a correlation. The remaining two studies reported no predictive value for VET with respect to flap failure or pedicle thrombosis.

Conclusion:

The results of this review suggest that VET, particularly parameters relating to clot strength, may help clinicians identify patients at risk for flap thrombosis. However, uncontrolled and heterogenous reporting limit definitive conclusions, and high-quality diagnostic studies are needed to better determine the clinical utility of viscoelastic testing for free flap patients.

Multidisciplinary Practice Variations of Anti-Thrombotic Strategies for Free Tissue Transfers

Background: Venous thrombosis, the leading cause of free flap failure, may have devastating consequences. Many anti-thrombotic agents and protocols have been described for prophylaxis and treatment of venous thrombosis in free flaps. Methods: National surveys were distributed to microsurgeons (of both Plastics and ENT training) and hematology and thrombosis specialists. Data were collected on routine screening practices, perceived risk factors for flap failure, and pre-, intra-, and post-operative anti-thrombotic strategies. Results: There were 722 surveys distributed with 132 (18%) respondents, consisting of 102 surgeons and 30 hematologists. Sixty-five surgeons and 9 hematologists routinely performed or managed patients with free flaps. The top 3 perceived risk factors for flap failure according to surgeons were medical co-morbidities, past arterial thrombosis, and thrombophilia. Hematologists, however, reported diabetes, smoking, and medical co-morbidities as the most important risk factors. Fifty-four percent of physicians routinely used unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH) as a preoperative agent. Surgeons routinely flushed the flap with heparin (37%), used UFH IV (6%), or both (8%) intra-operatively. Surgeons used a range of post-operative agents such as UFH, LMWH, aspirin, and dextran while hematologists preferred LMWH. There was variation of management strategies if flap thrombosis occurred. Different strategies consisted of changing recipient vessels, UFH IV, flushing the flap, adding post-operative agents, or a combination of strategies. Conclusions: There are diverse practice variations in anti-thrombotic strategies for free tissue transfers and a difference in perceived risk factors for flap failure that may affect patient management.

Outcomes in Head and Neck Free Flap Reconstruction Among Patients With a History of Venous Thromboembolism

OBJECTIVE

To investigate if a history of venous thromboembolism (VTE) is a risk factor for complications in head and neck free flap surgery by assessing outcomes among patients with a history of deep vein thrombosis (DVT) and/or pulmonary embolism (PE).

STUDY DESIGN

Retrospective cohort study.

SETTING

Single tertiary care center.

METHODS

All patients undergoing head and neck free flap reconstruction at our institution between September 1, 2006, and April 2, 2020, were assessed for inclusion. Patients with and without a history of DVT or PE preoperatively were identified and grouped for comparison. Groups were compared for demographics, comorbidities, and 30-day complications. Significance was assessed with chi-square and binary logistic regression analyses.

RESULTS

Of the 1061 patients meeting inclusion criteria, 40 (3.8%) had a history of VTE. These patients were significantly older (mean [SD], years: 67.8 [11.7] vs 63.0 [14.1], P = .038) and significantly more likely to have history of chemotherapy (35.0% vs 18.7%, P = .010) and stroke (27.5% vs 4.5%, P < .001). After accounting for patient characteristics via binary logistic regression, VTE was independently associated with an increased risk for postoperative thrombosis of the free flap pedicle (odds ratio [95% CI] = 3.65 [1.12-11.90], P = .032) and reoperation (2.45 [1.25-4.80], P = .009). Patients with history of PE had a significantly increased risk for flap failure (7.70 [1.77-33.52], P = .007). Prior VTE was not independently associated with an increased risk for medical complications or readmission.

CONCLUSION

Patients with a history of VTE may be at an increased risk for free flap compromise secondary to postoperative pedicle thrombosis. This risk should be considered in preoperative workup and postoperative monitoring.

The Impact of Coagulopathy on Clinical Outcomes following Microsurgical Breast Reconstruction

SUMMARY

Autologous breast reconstruction has evolved considerably from pedicled muscle-based approaches to microsurgical perforator-based techniques. Patients with documented coagulopathy, however, remain a particularly challenging population. The authors present their experience in microsurgical breast reconstruction in patients with coagulopathy and discuss their treatment protocol. A prospectively maintained database was queried for patients with coagulopathy who underwent microsurgical breast reconstruction between 2016 and 2019. Information regarding patient demographics, type of coagulopathy, and anticoagulation regimen were retrieved, and clinical outcomes were investigated. Nineteen patients who underwent 34 microsurgical breast reconstructions with free abdominal flaps were included in the study. The most common coagulopathy was factor V Leiden [n = 7 (38.6 percent)]. Nine patients (47.4 percent) developed thrombotic complications (the majority occurring intraoperatively); notably, arterial and venous thrombosis in four (21.1 percent) and two patients (10.5 percent), respectively. Postoperative thrombotic complications included pulmonary embolism [n = 2 (10.5 percent)] and flap congestion secondary to venous thrombosis [two flaps (5.9 percent)]. Only one flap loss was observed secondary to delayed venous thrombosis on postoperative day 6 (2.9 percent). The anticoagulation regimen in the majority of patients consisted of intraoperative intravenous administration of heparin (2000 U [bolus]) followed by a 5-day heparin infusion at 500 U/hour [n = 10 (52.6 percent)]. The high rate of thrombotic complications in patients with coagulopathy who underwent microsurgical breast reconstruction is contrasted by a low flap loss rate. Although coagulopathy is a risk factor for thrombotic complications, successful microsurgical breast reconstruction is still possible in the majority of patients.

Multiple Thrombi during Microvascular Anastomosis Caused by Decreased Antithrombin Activity: A Case Report

With recent advances in microsurgical instruments and technique, microvascular anastomosis has become a universal surgical technique; however, thrombosis still presents in a number of cases. Tension, twisting, and compression to the anastomotic site are the main causes of thrombus; however, disorder of the coagulation-fibrinolysis system also need to be considered. To date, only few reports exist regarding thrombosis caused by disorder of coagulant system in microvascular anastomosis. Here we report our 3 cases in which multiple thrombus formation occurred intraoperatively caused by decrease of antithrombin (AT) activity. AT activity was measured twice a day after vascular anastomosis: after surgery and up to 3 days after surgery. Thrombosis was not observed in any of the 3 patients intraoperatively after the transfusion, or thrombosis was not observed in any of 3 patients intraoperatively after the transfusion or postoperatively, and no other complications were observed. In these 3 cases, the thrombus was not caused by technical error or other previously described factors. The observed intraoperative decrease in AT activity was thought to be caused by thrombus formation. It is important that microsurgeons are reminded that disorders of the coagulation-fibrinolysis system could cause thrombosis.

Thromboelastometry for Assessing Risks of Free Flap Thrombosis in Patients Undergoing Microvascular Surgery

Introduction: Coagulation assessment is often missing in microvascular surgery. We aimed at evaluating the predictive value of thromboelastometry for free flap thrombosis in microvascular surgery patients. Materials and Methods: We enrolled 103 adult patients with traumatic injuries scheduled for microvascular free flap surgery into a prospective observational study. Thirty-six patients with recent trauma underwent surgery within 30 days (ES group), and were compared with 67 trauma patients who underwent surgery later than 30 days (late surgery, LS group) after the injury. Rotational thromboelastometry (RTE) was performed before surgery. Functional fibrinogen to platelet ratio (FPR) ≥ 42 was selected as the main hypercoagulability index. Free flap thrombosis was set as primary outcome. Thrombotic risk factors and duration of surgery related to free flap thrombosis were secondary outcomes. Statistical significance p < 0.05; not significant NS. Results: Six patients (16.7%) in the ES group and 10 (14.9%) in the LS group had free flap thrombosis (NS). In the entire cohort, free flap thrombosis rate increased in the presence of thrombogenic comorbidities (OR 4.059, CI 1.33-12.37; p = 0.014) and prolonged surgery times (OR 1.007, CI 1 - 1.012; p = 0.05). Although hypercoagulability occurred more frequently in the ES group (44.4%) than in the LS group (11.9%; p < 0.001), it was not associated with higher free flap thrombosis rate. In ES group patients with surgery times > 240 min, the risk of free flap thrombosis increased (OR 3.5, CI 1.16-10.6; p = 0.026) with 93.3% sensitivity and 86.7% specificity (AUC 0.85; p = 0.007). In contrast, in LS patients hypercoagulability increased the odds of free flap thrombosis (OR 8.83, CI 1.74-44.76; p = 0.009). Moreover, a positive correlation was found between FPR ≥ 42 and free flap thrombosis rate (r = 0.362; p = 0.003). In the LS group, the presence of thrombogenic comorbidities correlated with free flap thrombosis rate (OR 7, CI 1.591-30.8; p = 0.01). Conclusions: In LS patients with thrombogenic comorbidities, thromboelastometry supports the detection of hypercoagulability and predicts free flap thrombosis risk. In ES patients, postoperative hypercoagulability did not predict free flap thrombosis. Prolonged surgery time should be considered as a risk factor.

Free flap thrombosis in patients with hypercoagulability: A systematic review

Background

Even with satisfactory anastomosis technique and adequate experience of the surgeon, flap loss due to thrombosis can still occur due to the patient’s underlying condition. Patients with hypercoagulability due to etiologies such as malignancy, hereditary conditions, and acquired thrombophilia are among those who could benefit from free flap procedures. This review aimed to evaluate the risk of free flap thrombosis in patients with hypercoagulability and to identify the most effective thromboprophylaxis regimen.

Methods

This review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline. The PubMed, Embase, and Cochrane Library databases were explored. Types of free flaps, types of hypercoagulable states, thrombosis prevention protocols, thrombosis complication rates, and flap vitality outcomes were reviewed. Samples from the included studies were pooled to calculate the relative risk of free flap thrombosis complications in patients with hypercoagulability compared to those without hypercoagulability.

Results

In total, 885 articles underwent title, abstract, and full-text screening. Six articles met the inclusion criteria. The etiologies of hypercoagulability varied. The overall incidence of thrombosis and flap loss in hypercoagulable patients was 13% and 10.3%, respectively. The thrombosis risk was two times higher in hypercoagulable patients (P=0.074) than in controls. Thromboprophylaxis regimens were variable. Heparin was the most commonly used regimen.

Conclusions

Hypercoagulability did not significantly increase the risk of free flap thrombosis. The most effective thromboprophylaxis regimen could not be determined due to variation in the regimens. Further well-designed studies should be conducted to confirm this finding.

Polymorphism rs2066865 in the Fibrinogen Gamma Chain (FGG) Gene Increases Plasma Fibrinogen Concentration and Is Associated with an Increased Microvascular Thrombosis Rate

Background and Objective: Thrombosis due to inherited hypercoagulability is an issue that has been raised in microvascular flap surgery previously. We analyzed the association of a single nucleotide polymorphism (SNP) in rs2066865 in the fibrinogen gamma chain (FGG) gene, alteration in plasma fibrinogen concentration, and presence of microvascular flap thrombosis. Materials and Methods: A total of 104 adult patients with microvascular flap surgery were subjected to an analysis of the presence of SNP rs2066865 in the FGG gene. Alterations in plasma fibrinogen concentration according to genotype were determined as a primary outcome, and flap thrombosis was defined as a secondary outcome. Results: Flap thrombosis was detected in 11.5% of patients (n = 12). Successful revision of anastomosis was performed in four patients, resulting in a microvascular flap survival rate of 92.3%. We observed an increase in plasma fibrinogen concentration in genotype G/A and A/A carriers (G/G, 3.9 (IQR 4.76-3.04); G/A, 4.28 (IQR 5.38-3.18); A/A, 6.87 (IQR 8.25-5.49) (A/A vs. G/A, p = 0.003 and A/A vs. G/G, p = 0.001). Within group differences in microvascular flap thrombosis incidence rates were observed—G/G 6/79 (7.59%); G/A 5/22 (22.7%); A/A 1/3 (33.3%) (OR 0.30 95%; CI 0.044 to 0.57), p = 0.016; RR 3.2—when G/G versus G/A and A/A were analyzed respectively. Conclusions: A/A and G/A genotype carriers of a single nucleotide polymorphism in rs2066865 in the fibrinogen gamma chain gene had a higher plasma fibrinogen concentration, and this might be associated with an increased microvascular flap thrombosis incidence rate. Determined polymorphism could be considered as a genetic marker associated with microvascular flap thrombosis development. To confirm the results of this study, the data should be replicated in a greater sample size.

Venous Thromboembolism in Aesthetic Surgery: Risk Optimization in the Preoperative, Intraoperative, and Postoperative Settings

The purpose of this Continuing Medical Education (CME) article is to provide a framework for practicing surgeons to conceptualize and quantify venous thromboembolism risk among the aesthetic and ambulatory surgery population. The article provides a practical approach to identify and minimize venous thromboembolism risk in the preoperative, intraoperative, and postoperative settings.

Functional Outcomes After Heel Pad Reconstruction: A Review of 7 Cases

Sensate, durable heel pad reconstruction is challenging. The present study assessed the functional outcomes after heel pad reconstruction using various flap techniques at our institution. From June 2011 to June 2016 (5-year period), 7 consecutive patients underwent heel pad reconstruction for various etiologies, with 3 microvascular free flaps (42.9%; 2 musculocutaneous flaps [66.7%] and 1 contralateral medial plantar flap [33.3%]) and 4 local pedicle flaps (57.1%; 3 instep medial plantar artery flaps [75.0%] and 1 distally based reverse sural flap [25.0%]). The patient records and demographic data were reviewed, and surgically related information was obtained and analyzed. The subjective components of the American Orthopaedic Foot and Ankle Society hindfoot clinical ratings scale were used to evaluate the pain and functional outcomes. Sensation was assessed using Semmes-Weinstein monofilaments, and ulcer recurrence was recorded. The mean age of the patients was 41.7 (range 11 to 70) years, the mean defect size was 59 (range 12 to 270) cm², and the mean follow-up duration was 22 (range 15 to 43) months. Complete flap survival was achieved without significant complications in all 7 patients. Patients treated with the sensate medial plantar artery flap recorded the highest mean American Orthopaedic Foot and Ankle Society score of 57.3 (maximum score of 60) and experienced a return of deep sensation at 6 (range 6 to 24) months and protective sensation at 1 year. This was followed by the reverse sural flap and the musculocutaneous flap. No recurrent heel ulceration was observed in our series of patients. In conclusion, the sensate medial plantar flap is a satisfactory method for coverage of small- to moderate-size heel defects.