Perioperative thromboprophylaxis in liver transplant patients

Early pandemic in-hospital outcomes and mortality risk factors in COVID-19 solid organ transplant patients

Background

Solid organ transplant (SOT) recipients with COVID-19 have a higher risk of mortality than those without COVID-19. However, it is unclear how SOT patient outcomes compare to the general population without SOT who contract COVID-19.

Methods

We used the National Inpatient Sample from January to December 2020 to investigate inpatient outcomes seen in SOT recipients after contracting COVID-19 compared to nontransplant patients. We identified our study sample using ICD-10 CM and excluded those <18 years of age and those with dual organ transplants. Inpatient outcomes were compared in SOT and non-SOT COVID cohorts, and we further evaluated predictors of mortality in the SOT with COVID population.

Results

Out of the 1,416,445 COVID-19 admissions included in the study, 8315 (0.59%) were single SOT recipients. Our analysis that adjusted for multiple baseline characteristics and comorbidities demonstrated that COVID-19 in SOT patients was associated with higher rates of acute kidney injury (adjusted odds ratio [aOR] 2.34, 95% confidence interval [CI] 1.81-3.02, P < 0.01), lower rates of acute respiratory distress syndrome (aOR 0.68, 95% CI 0.54-0.85, P < 0.01), and similar rates of cardiac arrest, pulmonary embolism, circulatory shock, cerebrovascular events, and in-hospital mortality. Age >65 was associated with mortality in SOT patients.

Conclusion

In this nationally representative sample, SOT patients presenting with COVID-19 experienced similar rates of mortality compared to those without SOT. SOT patients were more likely to develop acute kidney injury. Further research is needed to understand the complex relationship between transplant patient outcomes and COVID-19.

Increased Platelet Aggregation in Adults After Orthotopic Liver Transplantation Indicates Higher Probability of Early Postoperative Survival

BACKGROUND Studies have shown that increased platelet aggregation in patients with decompensated cirrhosis indicates higher risk of further decompensation and death, but studies on the association between platelet aggregation function and early postoperative survival in orthotopic liver transplantation (OLT) patients are rare. We conducted a retrospective study to investigate whole-blood platelet aggregation during the perioperative period of OLT patients and its association with clinical outcomes. MATERIAL AND METHODS Adult patients who underwent OLT between January 1 and April 30, 2021 were retrospectively reviewed. Laboratory test results indicating primary hemostasis were analyzed. The generalized linear model was used to investigate the association between primary hemostasis parameters and survival. RESULTS A total of 256 patients were enrolled. The median platelet count (PLT) was 61.5 (39.5-106.3)×109/L before transplantation. The median MA value was 43.1 (34.5-56.2) mm. From the 1st to the 3rd day after transplantation, PLT and MA both indicated a significant decrease. Two weeks after transplantation, PLT rose to 143.0 (85.0-209.0)×10⁹/L, and the MA value rose to 56.7 (52.2-62.7) mm. On multivariate analysis, PLT at 1 week after transplantation (OR: 1.07; P=0.006) and MA value (OR: 1.12; P=0.003) were independently associated with outcome. The AUROC of the model combined with MA value, MELD score, and age was 0.945 (95% CI: 0.911-0.978). CONCLUSIONS The change in primary hemostasis during the early postoperative period of adult OLT is mainly characterized by the increase of platelet count and function 14 days after transplantation. Higher PLT was associated with higher survival at 14 days after transplantation, while a higher PLT ratio was associated with survival at 3 months after transplantation. Based on comprehensive consideration, the model combined with MA value, MELD score, and age more reliably indicated the associated with early survival after 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.

Detection and quantification of perioperative heparin-like effects by rotational thromboelastometry in living-donor liver transplant recipients: A prospective observational study

Background and Aims

Heparin-like effects (HLEs) can affect hemostasis during liver transplantation. The aim of this study was to assess the perioperative incidence and severity of HLE with rotational thromboelastometry (ROTEM) and activated partial thromboplastin time (aPTT).

Material and Methods

ROTEM and aPTT were measured intraoperatively and on postoperative days (POD) 1, 3, and 7. HLE was identified if ROTEM INTEM/HEPTEM CT-ratio was >1.25 and severe forms of HLE when ratio was ≥2. Based on aPTT, HLE was defined when aPTT ratio was >1.25 (patient aPTT/control aPTT).

Results

Thirty-eight recipients were included. Variable degrees of HLE were detected by aPTT-ratio and INTEM/HEPTEM CT ratio. No significant correlation existed between both ratios. Based on INTEM/HEPTEM CT ratio, HLE was detected in 7/38 during anhepatic phase, 19/38 post-reperfusion, 10/38 on POD1, 4/38 on POD3, and 0/38 on POD7. Four cases of severe HLE were identified by INTEM/HEPTEM CT ratio only in the anhepatic phase. Postoperative infusion of unfractionated heparin led to mild-moderate HLE on POD1 and 3 as evident by both tests. Red blood cell and plasma transfusion were higher with severe HLE (1350 ± 191 ml and 3558 ± 1407 ml). Composite adverse outcome of any complication or death within 3 months for patients without HLE, mild-moderate HLE, and severe HLE as detected by ROTEM was 27.8%, 42.9%, and 66.7%, respectively.

Conclusion

INTEM/HEPTEM CT ratio was able to detect and quantify HLE as aPTT ratio. The ability of the INTEM/HEPTEM CT ratio to identify severe HLE earlier in the anhepatic phase needs to be studied in a larger population. HLE is self-limiting, but when identified in a severe form, it is associated with worse outcome.

Educational Review: Error traps in anesthesia for pediatric liver transplantation

Anesthetic and surgical techniques for the liver transplantation have progressed considerably over the past sixty years; however, this procedure is still fraught with substantial morbidity. To increase the safety culture associated with the liver transplantation, we detail nine error traps associated with anesthesia for pediatric liver transplantation. These potential pitfalls are divided into the operative phases: pre-operative preparation (Failure to have a dedicated anesthesia team for pediatric liver transplantation); pre-anhepatic (Failure to prepare for massive blood loss, Failure to monitor for coagulation abnormalities); anhepatic including reperfusion (Failure to prepare for clamping of the inferior vena cava, Failure to recognize metabolic changes, Failure to maintain homeostasis for reperfusion, Failure to prepare for Post-reperfusion syndrome); and post-anhepatic (Failure to optimize liver perfusion, Failure to maintain hemostatic balance). By offering practical advice on the preparation and treatment of these error traps, we aim to better prepare anesthesiologists to take care of pediatric patients undergoing the liver transplantation.

Intraoperative intracardiac thrombus in liver transplantation: A 9-year retrospective review focusing on treatment and outcomes

This study characterizes incidence and outcomes surrounding intracardiac thrombosis (ICT) during liver transplantation over 9 years at a single center before and after the routine use of transesophageal echocardiography (TEE). Adult liver transplantation patients from 2011 to 2020 were divided into eras based on routine TEE use. ICTs were identified by querying anesthetic records for search terms. Descriptive statistics included counts and proportions for baseline recipient, donor, intraoperative, and postoperative characteristics. Outcome data were based on date of hospital discharge and date of death. The incidence of ICT increased in the TEE era (2016-2020) compared with the pre-TEE era (2011-2015; 3.7% [25/685] vs. 1.9% [9/491]; p < 0.001). Patients with ICT had significantly higher Model for End-Stage Liver Disease-sodium (MELD-Na) scores, pretransplant hospitalization, malignancy, drug-induced liver injury, hypertension, deep vein thrombosis, reperfusion syndrome, transfused platelets and cryoprecipitate, and use of hemostatic medications. A higher proportion of patients in the ICT group underwent simultaneous liver-kidney transplantation. The patients with ICT were similar, except patients in the pre-TEE era had higher MELD-Na scores and incidences of hepatitis C virus and lower incidences of encephalopathy. In the pre-TEE era, all ICTs presented as intraoperative cardiac arrest, and the 30-day mortality in the setting of ICT was 66.7% (6/9). During the TEE era, 80% of ICTs were diagnosed incidentally or attributed to hemodynamic instability (p = 0.002). The 30-day mortality rate was 36% (9/25) in the TEE era (p = 0.25). ICT incidence increased in the TEE era, yet the mortality rate was lower, suggesting that routine intraoperative TEE may lead to the early detection of ICT prior to hemodynamic collapse.

The Choice between Plasma-Based Common Coagulation Tests and Cell-Based Viscoelastic Tests in Monitoring Hemostatic Competence: Not an either-or Proposition

There has been a significant interest in the last decade in the use of viscoelastic tests (VETs) to determine the hemostatic competence of bleeding patients. Previously, common coagulation tests (CCTs) such as the prothrombin time (PT) and partial thromboplastin time (PTT) were used to assist in the guidance of blood component and hemostatic adjunctive therapy for these patients. However, the experience of decades of VET use in liver failure with transplantation, cardiac surgery, and trauma has now spread to obstetrical hemorrhage and congenital and acquired coagulopathies. Since CCTs measure only 5 to 10% of the lifespan of a clot, these assays have been found to be of limited use for acute surgical and medical conditions, whereby rapid results are required. However, there are medical indications for the PT/PTT that cannot be supplanted by VETs. Therefore, the choice of whether to use a CCT or a VET to guide blood component therapy or hemostatic adjunctive therapy may often require consideration of both methodologies. In this review, we provide examples of the relative indications for CCTs and VETs in monitoring hemostatic competence of bleeding patients.

Consensus Statement on Hemostatic Management, Anticoagulation, and Antiplatelet Therapy in Liver Transplantation

Anticoagulation and antiplatelet therapies are increasingly used in liver transplant (LT) candidates and recipients due to cardiovascular comorbidities, portal vein thrombosis, or to manage posttransplant complications. The implementation of the new direct-acting oral anticoagulants and the recently developed antiplatelet drugs is a great challenge for transplant teams worldwide, as their activity must be monitored and their complications managed, in the absence of robust scientific evidence. In this changing and clinically heterogeneous scenario, the Spanish Society of Liver Transplantation and the Spanish Society of Thrombosis and Haemostasis aimed to achieve consensus regarding the indications, drugs, dosing, and timing of anticoagulation and antiplatelet therapies initiated from the inclusion of the patient on the waiting list to post-LT surveillance. A multidisciplinary group of experts composed by transplant hepatologists, surgeons, hematologists, transplant-specialized anesthesiologists, and intensivists performed a comprehensive review of the literature and identified 21 clinically relevant questions using the patient-intervention-comparison-outcome format. A preliminary list of recommendations was drafted and further validated using a modified Delphi approach by a panel of 24 transplant delegates, each representing a LT institution in Spain. The present consensus statement contains the key recommendations together with the core supporting scientific evidence, which will provide guidance for improved and more homogeneous clinical decision making.

Effects of total laparoscopic hysterectomy on the clinical outcomes of patients with uterine fibroids

OBJECTIVE

To clarify the effects of total laparoscopic hysterectomy (TLH) on sex hormone levels, quality of life (QOL) and complications such as lower-extremity deep vein thrombosis (DVT) in patients with uterine fibroids (UFs).

METHODS

In this retrospective study, 136 patients with UFs treated in Hainan General Hospital from March 2018 to December 2020 were collected as research participants, of which 65 patients received total abdominal hysterectomy (TAH) were included in the control group and 71 patients who received TLH were assigned to the research group. The two groups were compared regarding the following items: response rate, surgical indexes, rehabilitation indicators, changes in sex hormone levels and QOL, and the occurrence of lower-extremity DVT.

RESULTS

The research group showed a significantly higher response rate, and better indicators of surgical treatment and rehabilitation than the control group (P<0.05). The sex hormones in the research group were more stable than that in the control group. The QOL was also significantly better and the incidence of total complications was statistically lower in the research group compared with the control group (both P<0.05).

CONCLUSIONS

TLH is a feasible and safe alternative than traditional TAH for UFs, as it can effectively improve patients' sex hormone levels and QOL, and reduce the incidence of complications, which is worthy of clinical promotion.

Perioperative cangrelor in patients with recent percutaneous coronary intervention undergoing liver transplantation: A case series

BACKGROUND

Management of dual antiplatelet therapy (DAPT) in the perioperative setting is challenging, particularly in complex patient populations, such as those with underlying coagulopathy and/or recent percutaneous coronary interventions.

METHODS

In this case series, we describe the perioperative use of cangrelor bridge therapy in two patients undergoing liver transplantation after recent coronary drug-eluting stent placement.

OUTCOMES

In both patient cases, cangrelor use as a P2Y12 bridge at a dose of 0.75 μg/kg/min was safe and effective. Both patients were successfully switched back to their oral DAPT regimen post-operatively without additive bleeding or thrombotic complications.

CONCLUSION

The use of cangrelor as bridge therapy in high-risk perioperative liver transplant patients appears to be a viable option when DAPT is warranted.

Antiplatelet drugs and liver fibrosis

Liver fibrosis results from an imbalance between extracellular matrix formation and degradation. The background of liver fibrosis is chronic inflammation and subsequent microcirculation disturbance including microthrombosis. Platelets actively participate in liver fibrosis not only as a part of the clotting system but also by releasing granules containing important mediators. In fact, platelets may play a dual role in the pathophysiology of liver fibrosis as they are able to stimulate regeneration as well as aggravate the destruction of the liver. Recent studies revealed that antiplatelet therapy correlates with inhibition of liver fibrosis. However, liver impairment is associated with extensive coagulation disorders thus the safety of antiplatelet therapy is an area for detailed exploration. In this review, the role of platelets in liver fibrosis and accompanying hemostatic disorders are discussed. Additionally, results of animal and human studies on antiplatelet drugs in liver disorders and their potential therapeutic utility are presented.

Hepatic Artery Thrombosis After Orthotopic Liver Transplant: Experience in the Last 10 Years

BACKGROUND

Hepatic artery thrombosis (HAT) is the second cause of graft failure, after primary disfunction. It has a significant morbidity, with a retransplant and mortality rate in early hepatic artery thrombosis of 50%. The incidence of this event goes from 2% to 9% in the adult population.

METHODS

The objective is to assess the incidence of HAT in a third-level hospital. The study design is an observational retrospective study, collecting data of the transplant recipient from 2010 to 2020.

RESULTS

Incidence of HAT was 5.33% (39/732). A statistical difference was found with the blood intraoperative administration (P = .002) and with the presence of anatomic abnormalities in the hepatic artery between the HAT and the non-HAT group. We did not find any statistical difference with portal thrombosis (P = .73) between the groups.

CONCLUSIONS

HAT is a fatal complication after an orthotopic liver transplant, which can lead to graft loss and even recipient death. For these reasons, we should early identify risk factors associated with this event early and try to minimize them to avoid the devastating consequences.

Case Report of a Patient Treated With Acenocumarol Awaiting Orthotopic Liver Transplant: Perioperative Coagulation Management and Risk for Hepatic Artery Thrombosis

BACKGROUND

End-stage liver disease is associated with a concomitant reduction of pro- and anticoagulant factors that typically leads to rebalanced hemostasis. This rebalanced hemostasis can be easily disturbed, encountering both hemostasis-related bleeding episodes and thrombotic events.

METHODS

This article reports a case of a 52-year-old man diagnosed with portal vein thrombosis and treated with Acenocumarol. The patient received ortothopic liver transplant. The preprocedure international normalized ratio was 3.5. A transfusion of 2000 units of prothrombin complex concentrate was indicated by Hematology.

RESULTS

Repeated intra- and postoperative hepatic artery thrombosis resulted in graft loss and patient retransplantation in first 24 hours.

CONCLUSIONS

The new concept of rebalanced hemostasis in these patients forces us to change our clinical decisions in preoperative coagulation management, avoiding old practices based on the traditional model such as transfusion guided by international normalized ratio and platelet count, among others that will be analyzed in present work.

Vascular surgery in liver resection

Vascular surgery in liver resection is a standard part of liver transplantation, but is also used in oncological liver surgery. Malignant liver tumors with vascular involvement have a poor prognosis without resection. Surgery is currently the only treatment to provide long-term survival in advanced hepatic malignancy. Even though extended liver resections are increasingly performed, vascular involvement with need of vascular reconstruction is still considered a contraindication for surgery in many institutions. However, vascular resection and reconstruction in liver surgery-despite being complex procedures-are safely performed in specialized centers. The improvements of the postoperative results with reduced postoperative morbidity and mortality are a result of rising surgical and anesthesiological experience and advancements in multimodal treatment concepts with preconditioning measures regarding liver function and systemic treatment options. This review focuses on vascular surgery in oncological liver resections. Even though many surgical techniques were developed and are also used during liver transplantation, this special procedure is not particularly covered within this review article. We provide a summary of vascular reconstruction techniques in oncological liver surgery according to the literature and present also our own experience. We aim to outline the current advances and standards in extended surgical procedures for liver tumors with vascular involvement established in specialized centers, since curative resection improves long-term survival and shifts palliative concepts to curative therapy.

Thromboelastography profiles for controlled circulatory death donors: Validating the role of heparin

Controlled donation after circulatory death (cDCD) liver transplants are associated with increased ischemic-type biliary complications. Microvascular thrombosis secondary to decreased donor fibrinolysis may contribute to bile duct injury. We hypothesized that cDCD donors are hypercoagulable with impaired fibrinolysis and aim to use thromboelastography to characterize cDCD coagulation profiles.

Perioperative blood transfusion decreases long-term survival in pediatric living donor liver transplantation

BACKGROUND

The impact of perioperative blood transfusion on short- and long-term outcomes in pediatric living donor liver transplantation (PLDLT) must still be ascertained, mainly among young children. Clinical and surgical postoperative complications related to perioperative blood transfusion are well described up to three months after adult liver transplantation.

AIM

To determine whether transfusion is associated with early and late postoperative complications and mortality in small patients undergoing PLDLT.

METHODS

We evaluated the effects of perioperative transfusion on postoperative complications in recipients up to 20 kg of body weight, submitted to PLDLT. A total of 240 patients were retrospectively allocated into two groups according to postoperative complications: Minor complications (n = 109) and major complications (n = 131). Multiple logistic regression analysis identified the volume of perioperative packed red blood cells (RBC) transfusion as the only independent risk factor for major postoperative complications. The receiver operating characteristic curve was drawn to identify the optimal volume of the perioperative RBC transfusion related to the presence of major postoperative complications, defining a cutoff point of 27.5 mL/kg. Subsequently, patients were reallocated to a low-volume transfusion group (LTr; n = 103, RBC ≤ 27.5 mL/kg) and a high-volume transfusion group (HTr; n = 137, RBC > 27.5 mL/kg) so that the outcome could be analyzed.

RESULTS

High-volume transfusion was associated with an increased number of major complications and mortality during hospitalization up to a 10-year follow-up period. During a short-term period, the HTr showed an increase in major infectious, cardiovascular, respiratory, and bleeding complications, with a decrease in rejection complications compared to the LTr. Over a long-term period, the HTr showed an increase in major infectious, cardiovascular, respiratory, and minor neoplastic complications, with a decrease in rejection complications. Additionally, Cox hazard regression found that high-volume RBC transfusion increased the mortality risk by 3.031-fold compared to low-volume transfusion. The Kaplan-Meier survival curves of the studied groups were compared using log-rank tests and the analysis showed significantly decreased graft survival, but with no impact in patient survival related to major complications. On the other hand, there was a significant decrease in both graft and patient survival, with high-volume RBC transfusion.

CONCLUSION

Transfusion of RBC volume higher than 27.5 mL/kg during the perioperative period is associated with a significant increase in short- and long-term postoperative morbidity and mortality after PLDLT.

Utility of viscoelastic coagulation testing in liver surgery: a systematic review

BACKGROUND

The objective of the current study was to summarize and evaluate all published evidence regarding viscoelastic testing in the field of liver surgery.

METHODS

A systematic search of the literature was performed using Medline/PubMed, Scopus, Cochrane Library Central, Google Scholar, and clinicaltrials.gov databases. The following keywords were used:"Thromboelastography", "Thromboelastometry", "Viscoelastic tests OR testing", "Sonoclot Devices", "Point-of-care tests OR testing", "Coagulation OR Haemostasis OR Hemostasis", "Liver OR Hepatic Surgery", "Cirrhosis."

RESULTS

A total of 12 studies analyzing 348 patients who underwent viscoelastic testing of coagulation during liver surgery for benign or malignant diseases were included; 7 (58.3%) studies reported on the use of thromboelastography (TEG), and 5 (41.7%) reported on rotational thromboelastometry (ROTEM). Viscoelastic testing (TEG and ROTEM) identified normo-, hyper- and hypo-coagulable status in 77% (n = 268/348), 18.4% (n = 64/348), and 4.6% (n = 16/348) of patients, respectively. In contrast, conventional coagulation tests indicated normo-coagulability in 111 patients (34.2% out of 325) and hypo-coagulability in 214 (65.8% out of 325) patients following liver resection. No patient (0% out of 291) experienced postoperative hemorrhage, whereas 5.8% (n = 17/291) experienced postoperative thromboembolic events.

CONCLUSIONS

Global viscoelastic testing may be a reasonable adjunct to conventional coagulation testing to provide a more robust assessment of the coagulation status of patients undergoing liver surgery.

Pediatric liver transplantation in Australia and New Zealand: The case for a collaborative anesthetic database

BACKGROUND

Liver transplantation is conducted with strict oversight of organizational structure and clinical practice. However, specific regulations pertaining to the delivery of anesthetic services are lacking and consideration of departmental structure and mechanisms for quality control must occur at a local level. Busy centers collect and process sufficient data to guide this process but those with low case loads may not generate enough data for useful analysis. In Australia and New Zealand, pediatric liver transplants are performed at only four locations. As these operations are not equally distributed geographically or temporally there are periods of low activity at some centers. As anesthesia affects patient outcome, quality assurance activities are important in this setting.

AIMS

Provide a global overview of the structure and function of liver transplantation networks. Identify issues related to provision of pediatric anesthetic services with specific reference to Australasia. Examine anesthetic data from a single pediatric center to illustrate benefits and limitations of such activity.

METHODS

Pediatric liver transplant centers from Australia and New Zealand were surveyed to determine the organizational and logistical issues related to a liver transplant service. An audit of 15 years of liver transplants from a single center was conducted for benchmarking purposes and to identify changes in anesthetic practice over time.

RESULTS

Pediatric liver transplants performed in Queensland from January 2005 to December 2019 were reviewed. Changes in transfusion practice reflected international trends. Morbidity and mortality were comparable to international data. Important complications such as hepatic artery and portal vein thrombosis were uncommon and did not generate enough data for further analysis.

CONCLUSIONS

Combining the anesthetic liver transplant data from all sites in a single registry would expand data collection and generate broadly applicable findings. We propose the establishment of an Australasian pediatric anesthetic liver transplant database.

Venous thromboembolism in solid-organ transplant recipients: Findings from the RIETE registry

BACKGROUND

Venous thromboembolism (VTE) represents a relevant cause of morbidity in patients with solid-organ transplant (SOT), but there are scarce data on the management and outcomes in these patients.

METHODS

RIETE is a worldwide, ongoing observational registry of patients with objectively confirmed, acute VTE. We used the RIETE database to compare the clinical characteristics, treatment and outcomes in SOT recipients vs. non-recipients.

RESULTS

From January 2001 to December 2019, 83,210 patients were enrolled in RIETE. Of these, 329 (0.4%) were SOT recipients: in the kidney 221, liver 41, lung 28 and heart 25. Median duration of anticoagulation was similar in SOT recipients and non-recipients (174 vs. 182 days). During anticoagulation, 1180 patients developed deep vein thrombosis (DVT) recurrences, 1028 pulmonary embolism (PE) recurrences, 2392 had major bleeding, 3119 non-major bleeding and 8157 died. SOT recipients had a higher rate of major bleeding (hazard ratio [HR]: 2.55; 95% CI: 1.62-3.84) and clinically relevant non-major bleeding (HR: 1.94; 95% CI: 1.23-2.93) than non-recipients, with no differences in the rates of DVT recurrences (HR: 0.96; 95% CI: 0.30-2.32), PE recurrences (HR: 1.11; 95% CI: 0.35-2.67) or death (HR: 0.98; 95% CI: 0.67-1.40). On multivariable analysis, only liver transplant recipients were at an increased risk for major bleeding compared to non-recipients (adjusted HR: 3.17; 95% CI: 1.02-9.87).

CONCLUSIONS

Treatment of VTE in SOT recipients is associated with an increased risk of bleeding compared to non-recipients. This is mainly due to the influence of liver transplant recipients. In non-liver SOT recipients, the risk for bleeding was similar to that in non-recipients.

2020 Clinical Update in Liver Transplantation

The gold standard treatment of end-stage liver disease continues to be liver transplantation (LT). The challenges of LT require skilled anesthesiologists to anticipate physiologic changes associated with end-stage liver disease and surgical considerations that affect multiple organ systems. While on the waiting list, patients may be placed on new anticoagulation medications that can confound already complex coagulopathy in LT patients. Pain management often is an afterthought for such a complex procedure, but appropriate medications can help control pain while limiting opioid medications. Surgical stress and medications for immunosuppression can affect perioperative glucose management in ways that have implications for patient and graft survival. The coronavirus disease 2019 pandemic in 2020 provided a new challenge for anesthesiologists. The uncertainty of the novel respiratory virus challenged providers beyond just LT patients.

Perioperative thrombelastography serves as an important assessment tool of transfusion requirements during liver transplantation

Background

Thrombelastography has become increasingly used in liver transplantation. The implications of thrombelastography at various stages of liver transplantation, however, remain poorly understood. Our goal was to examine thrombelastography-based coagulopathy profiles in liver transplantation and determine whether preoperative thrombelastography is predictive of transfusion requirements perioperatively.

Methods

A retrospective review of 364 liver transplantations from January 2013 to May 2017 at a single institution was performed. Patients were categorized as hypocoagulable or nonhypocoagulable based on their preoperative thrombelastography profile. The primary outcome was intraoperative transfusion requirements.

Results

Of patients undergoing liver transplantation, 47% (n = 170) were hypocoagulable and 53% (n = 194) were nonhypocoagulable preoperatively. Hypocoagulable patients had higher transfusion requirements compared to nonhypocoagulable patients, requiring more units of packed red blood cells (7 vs 4, P < .01), fresh frozen plasma (14 vs 8, P < .01), cryoprecipitate (2 vs 1, P < .01), platelets (3 vs 2, P < .01), and cell saver (3 vs 2 L, P < .01). Additionally, these patients were more likely to receive platelets and cryoprecipitate in the first 24 hours following liver transplantation (both P < .05). No differences were found between rates of intensive care unit length of stay, 30-day readmission, or mortality.

Conclusion

Coagulation abnormalities are common among liver transplantation patients and can be identified using thrombelastography. Identification of a patient's coagulation state preoperatively aids in guiding transfusion during liver transplantation. This work serves to better direct clinicians during major surgery to improve perioperative resource utilization. Future prospective work should aim to identify specific thrombelastography values that may predict transfusion requirements.

Massive Pulmonary Artery Thromboembolism in a Liver Transplant Recipient: Case Study and Literature Review

The hypercoagulable state in liver transplant recipients that may manifest as abnormal thrombus formation in large vessel structures, such as cardiac chambers and the pulmonary arteries, poses a substantial threat for the patient and graft survival. Massive pulmonary embolism is a rare, albeit potentially lethal, complication that may occur at any stage of liver transplant surgery. In this study, we present the case of a major perioperative thromboembolic event in a liver transplant recipient that had taken place in the early post-transplant period during the second-look surgery that was then successfully treated by catheter-directed clot removal. We will attempt to identify potential factors that may have been associated with abnormal thrombus formation.

Imaging post liver transplantation part I: vascular complications

Liver transplantation continues to rise in frequency, with over 1,000 procedures performed in the UK in 2018. Complications are increasingly uncommon but when they occur, early recognition and intervention is vital to save grafts. Imaging after the perioperative period is often performed at patients' local hospitals meaning that all radiologists and sonographers need to have an understanding of how to assess a transplant liver. Part I of this series will focus on vascular complications, including the normal postoperative vascular anatomy following liver transplantation, normal post-transplantation vascular imaging findings and abnormal findings that may prompt further investigation. Vascular complications following liver transplantation will be illustrated using a collection of cases.

Hepatic Artery Thrombosis and Takotsubo Syndrome After Liver Transplantation - Which Came First?

BACKGROUND Takotsubo syndrome is a transient, reversible, stress-induced cardiomyopathy that affects only 1.4% of liver transplant patients and can cause complications, including cardiogenic shock, arrhythmia, and thromboembolism. Hepatic artery thrombosis is also rare, affecting just 2-4% of these patients, but can have disastrous consequences. Here, we describe a case of concurrent takotsubo syndrome and hepatic artery thrombosis in a postoperative liver transplant recipient. CASE REPORT The patient was a 66-year-old man who underwent living donor liver transplantation for non-alcoholic steatohepatitis. On postoperative day 3, he became lethargic and tachycardic to the 120 s. Work-up, including EKG, troponin I, BNP, and transthoracic echocardiogram, was characteristic for takotsubo syndrome. His LVEF of 15-20% was markedly reduced compared to his baseline of 50-55% from 6 months prior. Hepatic ultrasonography showed no hepatic arterial flow, prompting emergent return to the OR, where intraoperative evaluation revealed hepatic artery thrombosis. The graft was salvaged after hepatic artery thrombectomy and arterial anastomosis revision. We are unable to determine which event caused the other in this case, as both takotsubo syndrome and hepatic artery thrombosis manifested within the same time frame. CONCLUSIONS It is important to recognize takotsubo syndrome as a potential cause of cardiac dysfunction and hepatic artery thrombosis in liver transplant patients, and also be aware that hepatic artery thrombosis can precipitate takotsubo syndrome.

Liver function after transplantation in the assessment of the coagulation system and the concept of antithrombotic therapy

Introduction

Thrombotic complications after liver transplantation limit the long-term success of the procedure. Therefore, an early and accurate diagnosis with the appropriate treatment is crucial to sustain the proper functioning of the graft.

Aim

To evaluate the return of newly transplanted liver function within the first days of ICU stay after liver transplantation surgery (Ltx) observed in laboratory examination. It is important to understand the physiology of the newly transplanted liver, particularly in terms of its metabolic function and the assessment of easy-to-monitor coagulation parameters and enzyme markers.

Material and methods

We present our observations carried out in 27 patients, transplanted in the period 2015-2017, during their stay in the Department of Anaesthesiology and Intensive Therapy of the University Hospital in Wroclaw. We demonstrated changes in laboratory parameters within 72 h after liver transplantation and the concept of anticoagulant therapy at our institution.

Results

The presented results show the characteristics of aspartate transaminase, alanine transaminase, bilirubin, and standard tests evaluating the coagulation system within the first 4 days after surgery. The concept of anticoagulant therapy used in our intensive care unit is also presented. The aim of the work is an observation of physiology of the graft function in the aspect of coagulation disorders.

Conclusions

The early postoperative period is considered prognostic. The characteristics of basic biochemical tests are determined by the function of the transplanted organ. Implementation of anticoagulant therapy in this period is a therapeutic challenge that requires experience.

Projected 20- and 30-Year Outcomes for Pediatric Liver Transplant Recipients in the United States

BACKGROUND

Observed long-term outcomes no longer reflect the survival trajectory facing pediatric liver transplant (LT) recipients today. We aimed to use national registry data and parametric models to project 20- and 30-year post-transplant outcomes for recently transplanted pediatric LT recipients.

METHODS

We conducted a retrospective cohort study of 13,442 first-time pediatric (age <18) LT recipients using 1987 to 2018 Scientific Registry of Transplant Recipients data. We validated the proposed method (ie, to project long-term patient and graft survival using parametric survival models and short-term data) in 2 historic cohorts (1987-1996 and 1997-2006) and estimated long-term projections among patients transplanted between 2007 and 2018. Projections were stratified by raft type, recipient age, and indication for transplant.

RESULTS

Parsimonious parametric models with Weibull distribution can be applied to post-transplant data and used to project long-term outcomes for pediatric LT recipients beyond observed data. Projected 20-year patient survival for pediatric LT recipients transplanted in 2007 to 2018 was 84.0% (95% confidence interval 81.5-85.8), compared to observed 20-year survival of 72.8% and 63.6% among those transplanted in 1997 to 2006 and 1987 to 1996, respectively. Projected 30-year survival for pediatric LT recipients in 2007 to 2018 was 80.1% (75.2-82.7), compared to projected 30-year survival of 68.6% (66.1-70.9) in the 1997 to 2006 cohort and observed 30-year survival of 57.5% in the 1987 to 1996 cohort. Twenty- and 30-year patient and graft survival varied slightly by recipient age, graft type, and indication for transplant.

CONCLUSIONS

Projected long-term outcomes for recently transplanted pediatric LT recipients are excellent, reflective of substantial improvements in medical care, and informative for physician-patient education and decision making in the current era.

Clinical study of argatroban for preventing vascular thrombosis in the early period after pediatric living-related donor liver transplantation

OBJECTIVE

To evaluate the effect of heparin and argatroban on coagulation function and vascular thrombosis in the early period after pediatric LRDLT.

METHOD

Eighty-four congenital biliary atresia pediatric patients who had undergone LRDLT were studied. Patients were divided into two groups according to the method of anticoagulation (heparin or argatroban). AT-Ⅲ activity, APTT, and INR of the two groups were measured in the first 5 days after LRDLT. Vascular thrombosis was investigated by Doppler ultrasound daily.

RESULTS

There were no significant differences in gender, age, weight, graft-recipient weight ratio, and Kasai procedure between the two groups. The AT-Ⅲ activity of the two groups was low and increased gradually after surgery, with no significant difference between the two groups. There was no significant difference of APTT between the two groups immediately after and in the first day after surgery. After anticoagulation treatment, a significant difference in APTT between the two groups was observed. The incidences of vascular thrombosis were 4.76% (3/63) and 0% (0/21) in the heparin and argatroban groups, respectively, with no significant difference between the two groups. During the treatment, no serious complications such as active hemorrhage or drug allergy were observed in the two groups.

CONCLUSION

Argatroban is a direct anticoagulant, which is independent of AT-Ⅲ activity. Argatroban might be an alternative to heparin in uncomplicated LRDLT with recovered hepatic and coagulation function.

Impact of Hepatic Artery Variations and Reconstructions on the Outcome of Orthotopic Liver Transplantation

BACKGROUND

Donor variational arteries often require complex reconstruction.

METHODS

We analysed the incidence of different variations, types of arterial reconstructions and their impact on post-operative results from 409 patients undergoing liver transplantation at Karolinska Institute between 2007 and 2015.

RESULTS

A total of 292 (71.4%) liver grafts had a standard hepatic artery (SHA), and 117 (28.6%) showed hepatic artery variants (HAV). 58% of HAV needed reconstruction. The main variations were variant left hepatic artery (45.3%) from the gastric artery; variant right hepatic artery (38.5%); and a triple combination of variant right and left hepatic artery and the proper hepatic artery from the common hepatic artery (12.8%); other 3.4%. Patients/graft survival and arterial complications were not different between SHA and HAV. Incidence of biliary stricture was numerically higher in left hepatic artery variants (p = 0.058) and in variants where no arterial reconstruction was performed (p = 0.001). Operation and arterial warm ischaemia time were longer in the HAV group. The need for intraoperative re-reconstruction was higher in the HAV group (p = 0.04). Intraoperative bleeding was larger after back-table reconstruction than with intraoperative reconstruction (p = 0.04).

CONCLUSION

No overall differences were found between the HAV and the SHA groups. Occurrence of a variant left hepatic artery and HAV with no reconstruction seems to increase the risk of biliary strictures.

Antithrombotic management and thrombosis rates in children post-liver transplantation: A case series and literature review

Thrombosis is a major postoperative complication in pediatric liver transplantation. There is marked heterogeneity in prophylactic antithrombotic therapies used, without established guidelines. This review summarizes current worldwide incidence of thrombotic events and compares antithrombotic therapies in children post-liver transplant, with comparison to our institution's experience. Of the twenty-three articles with sufficient detail to compare antithrombotic regimens, the overall incidence of thrombosis ranged from 2.4% to 17.3%. Incidence of HAT ranged from 0% to 28.1%, of HVT from 0% to 4.7%, of PVT from 1.5% to 11.2%, and of IVC thrombosis from 0% to 2.8%. Re-transplantation due to thrombosis ranged from 0% to 4.8%. Prophylactic antithrombotic therapies varied between studies, and bleeding complications were infrequently reported. Since 2010, 96 children underwent 100 liver transplants at our institution with thrombosis incidence comparable to international literature (HAT 6%, PVT 5%, IVC 1%, and HVT 0%). Re-transplantation due to thrombosis occurred in 2% and major bleeding occurred in 10%. The prophylactic antithrombotic therapies used post-liver transplantation in children remain varied. Low rates of thrombosis have been reported with antiplatelet use both with and without anticoagulation. Standard definitions and consistent reporting of bleeding complications are required, in addition to thrombosis rates, so that true risk-benefit assessment of reported regimes can be understood.

Cancer-Associated Thrombosis in Cirrhotic Patients with Hepatocellular Carcinoma

It is common knowledge that cancer patients are more prone to develop venous thromboembolic complications (VTE). It is therefore not surprising that patients with hepatocellular carcinoma (HCC) present with a significant risk of VTE, with the portal vein being the most frequent site (PVT). However, patients with HCC are peculiar as both cancer and liver cirrhosis are conditions that can perturb the hemostatic balance towards a prothrombotic state. Because HCC-related hypercoagulability is not clarified at all, the aim of the present review is to summarize the currently available knowledge on epidemiology and pathogenesis of non-malignant thrombotic complications in patients with liver cirrhosis and HCC. They are at increased risk to develop both PVT and non-splanchnic VTE, indicating that both local and systemic factors can foster the development of site-specific thrombosis. Recent studies have suggested multiple and often interrelated mechanisms through which HCC can tip the hemostatic balance of liver cirrhosis towards hypercoagulability. Described mechanisms include increased fibrinogen concentration/polymerization, thrombocytosis, and release of tissue factor-expressing extracellular vesicles. Currently, there are no specific guidelines on the use of thromboprophylaxis in this unique population. There is the urgent need of prospective studies assessing which patients have the highest prothrombotic profile and would therefore benefit from early thromboprophylaxis.