The Effects of Dextran on Postoperative Thrombosis and Hemodilution in Microvascular Head and Neck Reconstruction

The use of dextran may not have positive effects on microvascular free flap reconstruction: A matched cohort study

BACKGROUND

Dextran had been used in free flap reconstruction surgery to increase the patency of anastomotic vessels. This study aimed to evaluate the outcome of perioperative and postoperative dextran in free flap surgery.

METHODS

This was a single-center, retrospective study that enrolled 622 patients who received free flap surgery from 2016 to 2020. Propensity score matching was done to minimize the effect of covariance. The outcome included flap-related complications, hospital stay, and mortality. Differences in outcomes were compared between patients treated with dextran and those treated without dextran.

RESULTS

After propensity score matching, a total of 378 cases of free flap surgery were included. No difference in total flap failure rate, partial flap failure rate, take-back rate, or major and minor complications were found between the 2 groups. Dextran did not increase the overall complication rate of free flap surgery. Vascular thrombosis remains the most common cause of take-back re-exploration reasons in both the dextran and non-dextran groups.

CONCLUSIONS

We found that the use of dextran perioperatively combined with postoperative treatment in microvascular free flap reconstruction showed no statistical difference in flap survival rate and complication rate.

Dextran-40 Reduces Partial Flap Failure: A Systematic Review and Meta-analysis for Antithrombotics after Free Flaps

Background

Antithrombotic agents are used after free-flap surgery to prevent thrombus formation and improve flap outcomes. However, the reports vary. Therefore, this meta-analysis aimed to elucidate the need for antithrombotic agents in this context.

Methods

We searched for studies that compared the outcomes of patients undergoing free-flap surgery with or without postoperative antithrombotic agents in the PubMed, Cochrane, and ClinicalTrials.gov databases. The primary outcome was total flap failure, with secondary outcomes including partial flap failure, pedicle thrombosis, and bleeding/hematoma. The relative risks (RRs) of outcomes with or without antithrombotic use were evaluated.

Results

Fifteen studies (n = 6755 cases) were included. Antithrombotic agents did not reduce flap failure or pedicle thrombosis risks but increased bleeding and hematoma risks (RR, 1.535). Subgroup analyses by antiplatelet and anticoagulant use demonstrated results similar to those of antithrombotic use. The RR of bleeding/hematoma was 1.761 and 2.740 in the antiplatelet and anticoagulant groups, respectively. Postoperative dextran-40 administration reduced the risk of partial flap failure, with an RR of 0.535.

Conclusions

Postoperative antithrombotic, antiplatelet, or anticoagulant use did not change the risk of total/partial flap failure or pedicle thrombosis but increased the risk of hematoma/bleeding. Postoperative use of dextran-40 reduced the risk of partial flap failure. Increased intraflap blood flow may decrease the risk of partial flap failure. However, dextran-40 may cause severe pulmonary distress. Further prospective studies are required to evaluate the effects of these agents on thrombus formation, intraflap blood flow, and partial flap failure risk.

Evidence-Based Approaches to Anticoagulation in Reconstructive Microsurgery-A Systematic Literature Review

This systematic review addresses the crucial role of anticoagulation in microsurgical procedures, focusing on free flap reconstruction and replantation surgeries. The objective was to balance the prevention of thrombotic complications commonly leading to flap failure, with the risk of increased bleeding complications associated with anticoagulant use. A meticulous PubMed literature search following Evidence-Based-Practice principles yielded 79 relevant articles, including both clinical and animal studies. The full-texts were carefully reviewed and evaluated by the modified Coleman methodology score. Clinical studies revealed diverse perioperative regimens, primarily based on aspirin, heparin, and dextran. Meta-analyses demonstrated similar flap loss rates with heparin or aspirin. High doses of dalteparin or heparin, however, correlated with higher flap loss rates than low dose administration. Use of dextran is not recommended due to severe systemic complications. In animal studies, systemic heparin administration showed predominantly favorable results, while topical application and intraluminal irrigation consistently exhibited significant benefits in flap survival. The insights from this conducted systematic review serve as a foundational pillar towards the establishment of evidence-based guidelines for anticoagulation in microsurgery. An average Coleman score of 55 (maximum 103), indicating low overall study quality, however, emphasizes the need for large multi-institutional, randomized-clinical trials as the next vital step.

Intraoperative Infusion of Dextran Confers No Additional Benefit after Carotid Endarterectomy but Is Associated with Increased Perioperative Major Adverse Cardiac Events

BACKGROUND

Intraoperative dextran infusion has been associated with reduction of an embolic risk in patients undergoing carotid endarterectomy (CEA). Nonetheless, dextran has been associated with adverse reactions, including anaphylaxis, hemorrhage, cardiac, and renal complications. Herein, we aimed to compare the perioperative outcomes of CEA stratified by the use of intraoperative dextran infusion using a large multiinstitutional dataset.

METHODS

Patients undergoing CEA between 2008 and 2022 from the Vascular Quality Initiative database were reviewed. Patients were categorized by use of intraoperative dextran infusion, and demographics, procedural data, and in-hospital outcomes were compared. Logistic regression analysis was utilized to adjust for differences in patients while assessing the association between postoperative outcomes and intraoperative infusion of dextran.

RESULTS

Of 140,893 patients undergoing CEA, 9,935 (7.1%) patients had intraoperative dextran infusion. Patients with intraoperative dextran infusion were older with lower rates of symptomatic stenosis (24.7% vs. 29.3%; P < 0.001) and preoperative use of antiplatelets, anticoagulants and statins. Additionally, they were more likely to have severe carotid stenosis (>80%; 49% vs. 45%; P < 0.001) and undergo CEA under general anesthesia (96.4% vs. 92.3%; P < 0.001), with a more frequent use of shunt (64.4% vs. 49.5%; P < 0.001). After adjustment, multivariable analysis showed that intraoperative dextran infusion was associated with higher odds of in-hospital major adverse cardiac events (MACE), including myocardial infarction [MI] (odds ratio [OR], 1.76, 95% confidence interval [CI]: 1.34-2.3, P < 0.001), congestive heart failure [CHF] (OR, 2.15, 95% CI: 1.67-2.77, P = 0.001), and hemodynamic instability requiring vasoactive agents (OR, 1.08, 95% CI: 1.03-1.13, P = 0.001). However, it was not associated with decreased odds of stroke (OR, 0.92, 95% CI: 0.74-1.16, P = 0.489) or death (OR, 0.88, 95% CI: 0.58-1.35, P = 0.554). These trends persisted even when stratified by symptomatic status and degree of stenosis.

CONCLUSIONS

Intraoperative infusion of dextran was associated with increased odds of MACE, including MI, CHF, and persistent hemodynamic instability, without decreasing the risk of stroke perioperatively. Given these results, judicious use of dextran in patients undergoing CEA is recommended. Furthermore, careful perioperative cardiac management is warranted in select patients receiving intraoperative dextran during CEA.

Does anticoagulation improve outcomes of microvascular free flap reconstruction following head and neck surgery: a systematic review and meta-analysis

The commonest cause of microvascular free flap failure is thrombosis at the anastomosis. Pharmacological antithrombotic therapies have been used to mitigate this risk, but they carry the risk of bleeding and haematoma formation. To justify any intervention, it is necessary to evaluate the benefits and balance of risks. This meta-analysis aims to quantify the value of systemic anticoagulation during head and neck free tissue reconstruction. We performed a systematic review on the impact of additional prophylactic antithrombotic therapy on head and neck (H&N) free tissue transfer (on top and above the use of low molecular weight heparin to prevent deep vein thrombosis). We carried a PRISMA-guided literature review, following registration with PROSPERO. All studies analysing the possible impact of prophylactic anticoagulants on free flap surgery in the head and neck were eligible. The primary outcome was perioperative free flap complications (perioperative thrombosis, partial or total free flap failure, thrombo-embolic events, or re-exploration of anastomosis). Secondary outcomes included haematoma formation or bleeding complications requiring further intervention. We identified eight eligible studies out of 454. These included 3531 free flaps for H&N reconstruction. None of the assessed interventions demonstrated a statistically significant improvement in free flap outcomes. Accumulative analysis of all anti-coagulated groups demonstrated an increased relative risk of free flap complications [RR 1.54 (0.73-3.23)] compared to control albeit not statistically significant (p = 0.25). Pooled analysis from the included studies showed that the prophylactic use of therapeutic doses of anticoagulants significantly (p = 0.003) increased the risk of haematoma and bleeding requiring intervention [RR 2.98 (1.47-6.07)], without reducing the risk of free flap failure. Additional anticoagulation does not reduce the incidence of free flap thrombosis and failure. Unfractionated heparin (UFH) consistently increased the risk of free flap complications. The use of additional anticoagulation as 'prophylaxis' in the perioperative setting, increases the risk of haematoma and bleeding.

Free Flap Surgery Outcome Related to Antithrombotic Treatment Regime: An Analysis of 1000 Cases

Background:

Autologous free tissue transfer is today an integral part of reconstructive plastic surgery, but still lacks generally accepted guidelines regarding antithrombotic agents. We hypothesized that the overuse of antithrombotic agents could be a risk factor for free flap complications and therefore studied a treatment protocol adjustment.

Methods:

Consecutive free flaps between 2005 and 2020 at a single center were analyzed for complications in relation to the use of pre- and intraoperative treatment with three different antithrombotic agents. The use of preoperative low molecular weight heparin (LMWH), intraoperative heparin, and dextran were analyzed in relation to outcome variables, thromboembolic events, or reexploration for hematoma.

Results:

Nine hundred thirty-one patients underwent 1000 microvascular free flaps for breast (n = 487), head and neck (n = 365), and extremity (n = 148) reconstruction. Within the first postoperative week, 44 cases had a thromboembolic event and 58 cases underwent hematoma-related reexploration. In the multivariate analysis, thromboembolic events were associated with extremity reconstruction (P = 0.02) and smoking (P = 0.02). Hematoma-related reexploration was more common with triple antithrombotic therapy compared with all other treatment regimes (P < 0.05). The number of antithrombotic agents used perioperatively was linearly decreased, from three to none, over the elapsed time period (P < 0.001).

Conclusions:

Hematoma was the most common reason for reexploration and was further associated with the use of multiple antithrombotic agents. Cessation of triple treatment was associated with less hematomas and further reduction of antithrombotic agents did not result in any increase of thromboembolic events. Evidence-based guidelines are warranted for antithrombotic regimes in standard free flap surgery.