Epsilon-Aminocaproic Acid Has No Association With Thromboembolic Complications, Renal Failure, or Mortality After Liver Transplantation

Intracardiac thrombosis and pulmonary thromboembolism during liver transplantation: A systematic review and meta-analysis

Intracardiac thrombosis and/or pulmonary thromboembolism (ICT/PE) is a rare but devastating complication during liver transplantation. Its pathophysiology remains poorly understood, and successful treatment remains a challenge. This systematic review summarizes the available published clinical data regarding ICT/PE during liver transplantation. Databases were searched for all publications reporting on ICT/PE during liver transplantation. Data collected included its incidence, patient characteristics, the timing of diagnosis, treatment strategies, and patient outcomes. This review included 59 full-text citations. The point prevalence of ICT/PE was 1.42%. Thrombi were most often diagnosed during the neohepatic phase, particularly at allograft reperfusion. Intravenous heparin was effective in preventing early-stage thrombus from progressing further and restoring hemodynamics in 76.32% of patients it was utilized for; however, the addition of tissue plasminogen activator or sole use of tissue plasminogen activator offered diminishing returns. Despite all resuscitation efforts, the in-hospital mortality rate of an intraoperative ICT/PE was 40.42%, with nearly half of these patients dying intraoperatively. The results of our systematic review are an initial step for providing clinicians with data that can help identify higher-risk patients. The clinical implications of our results warrant the development of identification and management strategies for the timely and effective treatment of these tragic occurrences during liver transplantation.

2021 Clinical Update in Liver Transplantation

In 2021, the United States performed 9,236 liver transplantations, an increase of 3.7% from 2020. As the specialty of transplant anesthesiologist continues to grow, so does the body of evidence-based research to improve patient care. New technology in organ preservation offers the possibility of preserving marginal organs for transplant or improving the graft for transplantation. The sequalae of end-stage liver disease have wide-ranging consequences that affect neurologic outcomes of patients both during and after transplantation that anesthesiologists should monitor. Obesity presents several challenges for anesthesiologists. As an increasing number of patients with nonalcoholic steatohepatitis are listed for transplant, managing their multiple comorbidities can be challenging. Finally, the rebalanced hemostasis of end-stage liver disease can cause both bleeding and thrombus. Often, bleeding risks predominate as a concern, but anesthesiologists should be aware of risks of intracardiac thrombus and review therapeutic options for prevention and treatment.

Intraoperative transfusion management, antifibrinolytic therapy, coagulation monitoring and the impact on short-term outcomes after liver transplantation-A systematic review of the literature and expert panel recommendations

BACKGROUND

Liver transplantation (LT) is frequently complicated by coagulopathy associated with end-stage liver disease (ESLD), that is, often multifactorial.

OBJECTIVES

The objective of this systematic review was to identify evidence based intraoperative transfusion and coagulation management strategies that improve immediate and short-term outcomes after LT.

METHODS

PRISMA-guidelines and GRADE-approach were followed. Three subquestions were formulated. (Q); Q1: transfusion management; Q2: antifibrinolytic therapy; and Q3: coagulation monitoring.

RESULTS

Sixteen studies were included for Q1, six for Q2, and 10 for Q3. Q1: PRBC and platelet transfusions were associated with higher mortality. The use of prothrombin complex concentrate (PCC) and fibrinogen concentrate (FC) were not associated with reductions in intraoperative transfusion or increased thrombotic events. The use of cell salvage was not associated with hepatocellular carcinoma (HCC) recurrence or mortality. Cell salvage and transfusion education significantly decreased blood product transfusions. Q2: Epsilon-aminocaproic acid (EACA) and tranexamic acid (TXA) were not associated with decreased blood product transfusion, improvements in patient or graft survival, or increases in thrombotic events. Q3: Viscoelastic testing (VET) was associated with decreased allogeneic blood product transfusion compared to conventional coagulation tests (CCT) and is likely to be cost-effective. Coagulation management guided by VET may be associated with increases in FC and PCC use.

CONCLUSION

Q1: A specific blood product transfusion practice is not recommended (QOE; low | Recommendation; weak). Cell salvage and educational interventions are recommended (QOE: low | Grade of Recommendation: moderate). Q2: The routine use of antifibrinolytics is not recommended (QOE; low | Recommendation; weak). Q3: The use of VET is recommended (QOE; low-moderate | Recommendation; strong).

The Efficacy and Safety of Epsilon-Aminocaproic Acid for Perioperative Blood Management in Spinal Fusion Surgery: A Systematic Review and Meta-Analysis

BACKGROUND

Perioperative blood loss is a major concern in spinal fusion surgery and often requires blood transfusion. A large amount of perioperative blood loss might increase the risks of various perioperative complications. Recent clinical studies have focused on the perioperative administration of epsilon-aminocaproic acid (EACA) in spinal fusion surgery. The aim of this review was to evaluate the efficacy and safety of EACA in spinal fusion surgery.

METHODS

Electronic databases (MEDLINE, EMBASE, PubMed, and Cochrane Central Register of Controlled Trials) were systematically searched up to April 2021. Data on perioperative blood loss, blood transfusion, and complications were extracted and analyzed by RevMan software.

RESULTS

Six randomized controlled studies comprising 398 patients undergoing spinal fusion surgery were included in this systematic review. Compared with the control group, the EACA group had significantly lower total perioperative blood loss, postoperative blood loss, postoperative hemoglobin, postoperative blood transfusion units, total blood transfusion units, and postoperative red blood cell transfusion units. Additionally, no significant differences were observed between the EACA and control groups in intraoperative blood loss, intraoperative blood transfusion units, intraoperative crystalloid administered, hospital stays, operative time, perioperative respiratory complications, and wound bleeding.

CONCLUSIONS

EACA in patients undergoing spinal fusion surgery is effective in perioperative hemostasis without increasing the incidence of postoperative complications. However, more large-scale trials are needed to examine the long-term adverse side effects of EACA in spinal fusion surgery.

Risk Factors and Outcomes of Intracardiac Thrombosis During Orthotopic Liver Transplantation

BACKGROUND

Intracardiac thrombosis incidence during orthotopic liver transplantation is estimated at 0.36% to 6.2% with mortality up to 68%. We aimed to evaluate risk factors and outcomes related to intracardiac thrombosis during orthotopic liver transplantation.

MATERIALS AND METHODS

A comprehensive retrospective data review of 388 patients who underwent orthotopic liver transplantation at an urban transplant center from January 2013 to October 2016 was obtained.

RESULTS

Six patients were found to have documented intracardiac thrombosis; 4 cases were recognized during the reperfusion stage and 1 during pre-anhepatic stage. All allografts were procured from decreased donors with a median donor age of 44 years (interquartile range, 35.25-49.75) and the cause of death was listed as cerebrovascular accident in 5 donors. Preoperative demographic, clinical, laboratory, and historical risk factors did not differ in patients with thrombosis. None had a prior history of trans-jugular intrahepatic portosystemic shunt or gastrointestinal bleeding. Three patients had renal injury, but no intraoperative hemodialysis was performed. Transesophageal echocardiographic findings included elevated pulmonary artery pressure (1/6), right ventricular strain (1/6), and pulmonary artery thrombus (1/6). Three patients died intraoperatively. Tissue plasminogen activator alone was given to 1 patient who did not survive, intravenous heparin only to 1 patient with resolution, and a combination of both was used in 2 patients with clot resolution achieved.

CONCLUSION

Cardiac thrombosis should be considered in patients having hemodynamic compromise during liver transplantation. Transesophageal echocardiography is a useful diagnostic tool. Intracardiac thrombosis treatment remains challenging; however, using both thrombolytics and heparin could achieve better results.

A Pharmacokinetic and Pharmacodynamic Investigation of an ε-Aminocaproic Acid Regimen Designed for Cardiac Surgery With Cardiopulmonary Bypass

OBJECTIVE

To investigate the pharmacokinetics and pharmacodynamics of an ε-aminocaproic acid (EACA) regimen designed for cardiac surgery with cardiopulmonary bypass (CPB).

DESIGN

Prospective observational study requiring blood sampling to measure EACA concentrations and fibrinolysis markers (fibrinogen, D-dimer, α₂-antiplasmin, and tissue plasminogen activator-plasminogen activator inhibitor [tPA-PAI-1] complex).

SETTING

Single-center, tertiary medical center.

PARTICIPANTS

Patients who underwent cardiac surgery with CPB between 2018 and 2019 for aortic or mitral valve replacement/repair or coronary artery bypass grafting. Previous sternotomy patients were included.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

The pharmacokinetics of EACA, during CPB, were described by a 3-compartment disposition model. EACA concentrations were greater than 130 mg/L in all patients after CPB and in most patients during CPB. The D-dimer level trended up and reached a peak median level of 1.35 mg/L of fibrinogen equivalence units (FEU) at 15 minutes after protamine administration. The median change in D-dimer (ΔD-dimer) from baseline to 15 minutes after protamine was 0.34 (-0.48 to 3.81) mg/L FEU. ΔD-dimer did not correlate with EACA concentration intraoperatively, urine output, body weight, glomerular filtration rate, cell salvage volume, and ultrafiltration volume. The median 24-hour chest tube output was 445 (180-1,011) mL.

CONCLUSION

This regimen provided maximum EACA concentrations near the time of protamine administration, with a total perioperative dose of 15 g. Most patients had EACA concentrations greater than the target during CPB. ΔD-dimer did not correlate with EACA concentration. The median 24-hour chest tube output compared well to similar studies that used higher doses of EACA.

A review of hyperfibrinolysis in cats and dogs

The fibrinolytic system is activated concurrently with coagulation; it regulates haemostasis and prevents thrombosis by restricting clot formation to the area of vascular injury and dismantling the clot as healing occurs. Dysregulation of the fibrinolytic system, which results in hyperfibrinolysis, may manifest as clinically important haemorrhage. Hyperfibrinolysis occurs in cats and dogs secondary to a variety of congenital and acquired disorders. Acquired disorders associated with hyperfibrinolysis, such as trauma, cavitary effusions, liver disease and Angiostrongylus vasorum infection, are commonly encountered in primary care practice. In addition, delayed haemorrhage reported in greyhounds following trauma and routine surgical procedures has been attributed to a hyperfibrinolytic disorder, although this has yet to be characterised. The diagnosis of hyperfibrinolysis is challenging and, until recently, has relied on techniques that are not readily available outside referral hospitals. With the recent development of point-of-care viscoelastic techniques, assessment of fibrinolysis is now possible in referral practice. This will provide the opportunity to target haemorrhage due to hyperfibrinolysis with antifibrinolytic drugs and thereby reduce associated morbidity and mortality. The fibrinolytic system and the conditions associated with increased fibrinolytic activity in cats and dogs are the focus of this review article. In addition, laboratory and point-of-care techniques for assessing hyperfibrinolysis and antifibrinolytic treatment for patients with haemorrhage are reviewed.

Fibrinolytic Shutdown Is Associated With Intraoperative Thrombosis and Hemorrhage During Visceral Transplant

Background and Objective. End-stage liver disease is characterized by a precarious imbalance of hemostasis. Detrimental consequences of hypofibrinolysis, also known as fibrinolytic shutdown, have been recently demonstrated, and its significance in visceral (ie, an allograft that contains the intestine) transplant remains unknown. Design and Setting. To fill this gap, following institutional review board approval, this retrospective study included 49 adult recipients of visceral allografts (14 “visceral allograft without the liver” and 35 “multivisceral” with the liver) transplanted between 2010 and 2018 in a single university hospital, and for whom pre-incisional thromboelastography was available. Based on percent clot lysis 30 minutes after maximal amplitude, patients were stratified into 3 fibrinolysis phenotypes: fibrinolytic shutdown, physiologic fibrinolysis, and hyperfibrinolysis. Results. Fibrinolytic shutdown occurred in 57% of patients, with higher incidence in recipients of multivisceral transplant (69%) compared with visceral allograft without liver (29%) allografts ( P = .04). Fibrinolytic shutdown was associated with an increase in both intraoperative thrombosis and hemorrhage. Intraoperative thrombosis (18%) occurred only with multivisceral transplant, and accounted for 36% of in-hospital mortality. A clinically meaningful reduction in incidence of intraoperative thrombosis was noted in recipients who received intravenous heparin thromboprophylaxis. Logistic regression identified pretransplant platelet count as a risk factor for fibrinolytic shutdown (odds ratio = 0.992, 95% confidence interval = [0.984-0.998]; χ2= 7.8, P = .005). Conclusions. This study highlights fibrinolytic shutdown as a dominant and clinically important feature of the hemostatic imbalance in recipients undergoing visceral transplantation.

Perioperative management of the bleeding patient

Perioperative bleeding remains a major complication during and after surgery, resulting in increased morbidity and mortality. The principal causes of non-vascular sources of haemostatic perioperative bleeding are a preexisting undetected bleeding disorder, the nature of the operation itself, or acquired coagulation abnormalities secondary to haemorrhage, haemodilution, or haemostatic factor consumption. In the bleeding patient, standard therapeutic approaches include allogeneic blood product administration, concomitant pharmacologic agents, and increasing application of purified and recombinant haemostatic factors. Multiple haemostatic changes occur perioperatively after trauma and complex surgical procedures including cardiac surgery and liver transplantation. Novel strategies for both prophylaxis and therapy of perioperative bleeding include tranexamic acid, desmopressin, fibrinogen and prothrombin complex concentrates. Point-of-care patient testing using thromboelastography, rotational thromboelastometry, and platelet function assays has allowed for more detailed assessment of specific targeted therapy for haemostasis. Strategic multimodal management is needed to improve management, reduce allogeneic blood product administration, and minimize associated risks related to transfusion.

The Perioperative Efficacy and Safety of Antifibrinolytics in Adult Spinal Fusion Surgery: A Systematic Review and Meta-analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

Compare outcomes of adult patients undergoing spinal fusion surgery who receive and do not receive perioperative antifibrinolytics to reduce operative blood loss.

SUMMARY OF BACKGROUND DATA

The clinical potential for antifibrinolytics such as tranexamic acid and epsilon aminocaproic acid to significantly reduce blood loss during adult spinal fusion surgery remains underexplored. Outcomes for assessment included operative blood loss, and other surgical, clinical, and haematological outcomes.

METHODS

We followed the recommended Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines for systematic reviews. Electronic database searches identified 2041 for screening. Data were extracted and analyzed using meta-analysis of proportions.

RESULTS

A total of 11 randomized controlled trials with a total of 937 adult spinal fusion surgery patients were included for analysis. There were 472 (50%) patients who were treated with antifibrinolytics, with 345 of 472 (73%) and 127 of 472 (27%) receiving tranexamic acid and epsilon aminocaproic acid respectively. The use of antifibrinolytics was associated with significantly lower intraoperative (MD -127.08 mL; P = 0.002) and total blood loss (MD -229.76 mL; P < 0.00001), as well as incidence of blood transfusion (OR 0.58; P = 0.04). There was no significant difference with antifibrinolytic use in terms of many surgical parameters, including surgery duration (P = 0.50), overall complications (P = 0.21), and length of stay (P = 0.88). Finally, postoperative haemoglobin was significantly greater (MD 0.30 g/dL; P = 0.02) following antifibrinolytic use, with other haematological parameters mostly unaffected.

CONCLUSION

Based on the highest level comparative evidence available, the possibility for blood loss reduction in adult spinal fusion surgery with the use of perioperative antifibrinolytics is not unreasonable, as it appears both efficacious and safe. In addition to further, larger investigations to validate the associations found in this study, practical aspects such as cost-benefit analysis, and long-term follow-up will further enhance our understanding.

LEVEL OF EVIDENCE

1.

Coagulation Management During Liver Transplantation: Use of Fibrinogen Concentrate, Recombinant Activated Factor VII, Prothrombin Complex Concentrate, and Antifibrinolytics

Coagulation management, and transfusion practice in liver transplantation (LT) have been evolving in the recent years due to better understanding of coagulation abnormalities in end-stage liver disease, and clinical management of LT patients. Avoidance of allogeneic blood components is feasible in some patients, but multi-modal coagulation therapies may be necessary in others who develop complex coagulopathy due to hemorrhage, hemodilution, hypothermia, and acid-base disturbances. Transfusions of plasma and cryoprecipitate remain to be the mainstay therapy for procoagulant factor replacement during LT. Clinical efficacy and safety of these products are limited by logistic issues (eg, thawing), and mostly noninfectious complications. Considering potential alternatives to conventional transfusion is thus important to improve hemostatic resuscitation in complex LT cases. The present review is mainly focused on procoagulant properties of plasma and platelet transfusion, and currently available plasma-derived and recombinant factor concentrates, and antifibrinolytic agents in LT patients. The role of viscoelastic coagulation tests to guide specific component therapies will be also discussed.

Use of low-dose thrombolytics for treatment of intracardiac thrombus and massive pulmonary embolus after aborted liver transplant leads to recovery of right ventricular function and redo liver transplantation

This is a 61-year-old man with end-stage liver disease who experienced cardiac arrest secondary to a massive pulmonary embolus and intracardiac thrombus during cannulation for veno-venous extracorporeal membrane oxygenation (ECMO) in preparation for orthotopic liver transplantation (OLT). Surgery was aborted and the patient was taken back to the intensive care unit in cardiogenic shock on multiple vasopressors. The patient was unresponsive to heparin bolus and too high risk for systemic thrombolytics or embolectomy. He was ultimately treated with 12 mg total of alteplase through his pulmonary artery catheter over 3 hours. He had subsequent resolution of his cardiogenic shock and proceeded with successful liver transplantation 5 days after his initial event without any bleeding complications. Low-dose thrombolytic therapy in the setting of absolute contraindications to thrombolysis allowed for recovery of cardiac function and, ultimately redo OLT in a patient with otherwise little hope of survival.

Noteworthy Literature Published in 2016 for Abdominal Organ Transplantation Anesthesiologists

More than 3000 peer-reviewed publications on the topic of liver transplantation were published in 2016. The goal of this article is to provide a concise review of pertinent literature for anesthesiologists who participate in liver transplantation. The authors selected and presented 33 articles published in 2016 on the topics of MELD policy; cardiovascular, pulmonary, and renal issues; coagulation and transfusion; anesthetic agents; hemodynamic monitors; acute liver failure; and donor issues.