Thromboelastographic changes in liver and pancreatic cancer surgery: hypercoagulability, hypocoagulability or normocoagulability?

Assessing hypercoagulability and VTE risk using thromboelastography and Khorana score in women with cancers receiving chemotherapy

Venous thromboembolism (VTE) is a common occurrence in cancer and chemotherapy increases thrombosis risk. Current risk assessment models such as the Khorana score (KS) and its modifications have limitations in female cancers. We assessed the coagulation profile of a group of women cancer patients under chemotherapy using thromboelastography (TEG) to determine if this can inform VTE risk assessment. Cancer patients who planned to receive chemotherapy were recruited. Baseline demographics, cancer data, BMI, Khorana Score (KS), and VTE risk factors were recorded and patients were followed for 6 months, for any thrombotic events. A total of 36 patients aged 35-85 (18 breast, 11 endometrial, 7 ovarian cancer) were evaluated. Hypercoagulability was detected in 63% of patients post-chemo cycle 1 and 75% post-cycle 2, with a significant increase in MA (maximum amplitude) and CI (clotting index), reduction in R (reaction time), K (clot kinetics), and LY30 (lysis time after 30 min of MA). KS showed only 7% of patients were high risk, 23% were low, and 70% were intermediate risk. MA and CI significantly increased in patients with intermediate and high-risk KS when compared with the low-risk patients and MA was positively correlated with KS. Five patients developed actual VTE; 100% of the tested ones were hypercoagulable either post-cycle 1 or 2 and 80% were KS intermediate risk. TEG is a hypercoagulability marker and TEG-MA and CI can potentially assess VTE risk. Larger studies are needed to assess the utility of TEG as an adjuvant to KS to better predict VTE in specific female cancers.

The link between high factor VIII to protein C ratio values and poor liver function after major hepatectomy

Our goal was to assess the coagulation profile in the immediate postoperative time after major liver surgery and its association with the liver function. Our hypothesis is that a decreased synthesis of the coagulation factor levels reflects an impaired liver synthesis following hepatic resection and will be associated with poor outcomes. This is a prospective, observational study recruiting consecutive patients scheduled for major liver resection in a tertiary hospital. Coagulation profile was assessed by conventional assays, viscoelastic assays and coagulation factor levels preoperatively and, on postoperative days 1, 2 and 6. Factor VIII to protein C (FVIII/PC) ratio has been used as a surrogate marker of hemostatic imbalance. Liver function was measured with conventional and indocyanine green (ICG) clearance tests, which were obtained preoperatively and on postoperative days 1 and 2. Sixty patients were recruited and 51 were included in the study. There is a clear increase in FVIII/PC ratio after surgery, which was significantly associated with low liver function, being more pronounced beyond postoperative day 2 and in patients with poorer liver function ( P  < 0.001). High FVIII/PC ratio values were significantly associated with higher postoperative morbidity, prolonged ICU and hospital stay and less survival ( P  < 0.05). High FVIII/PC ratio on postoperative day 2 was found to be predictor of posthepatectomy liver failure (PHLF; area under the ROC curve = 0.8129). Early postoperative high FVIII/PC ratio values are associated with low liver function, PHLF and poorer outcomes in patients undergoing major hepatic resection.

Exploring clinical evaluation indicators for predicting coagulation in the extracorporeal circulation circuit in hemodialysis patients receiving individualized regional citrate anticoagulation-A single-center, retrospective clinical study

BACKGROUND

Citrate anticoagulation is an important anticoagulation method in hemodialysis (HD) but cannot completely prevent the occurrence of coagulation in the extracorporeal circulation (ECC) circuit, and the clinical coagulation status can significantly affect the effect of citrate anticoagulation. In this study, the relationships between clinical coagulation status indicators and coagulation in the ECC circuit in HD patients receiving individualized citrate anticoagulant were studied to explore indicators that may predict coagulation in the ECC circuit.

METHODS

This study was a single-center, retrospective clinical study, and clinical data and laboratory tests related to the coagulation status of HD patients receiving individualized regional citrate anticoagulation (RCA) were collected. The relationships between indicators commonly used in clinical practice to evaluate clinical coagulation status and coagulation in the ECC circuit were statistically analyzed to find indicators that can predict the occurrence of coagulation in the ECC circuit.

RESULTS

The individualized RCA had a good anticoagulation effect, and the actual citrate infusion rate in nearly 80% of the patients was within ±10% of the theoretical infusion rate. The combined diseases or conditions that affect the coagulation status in vivo may increase the incidence of coagulation in the ECC circuit. The clinical D-dimer level is an independent risk factor that affects and can predict coagulation in the ECC circuit, with a cutoff value of 2.03 mg/L, sensitivity of 59%, and specificity of 78%.

CONCLUSION

Individualized RCA can meet the needs of most HD treatments. Abnormal coagulation status in HD patients may increase the incidence of coagulation in the ECC circuit during individualized RCA for HD, and the D-dimer level can predict the occurrence of coagulation in the ECC circuit during this treatment.

An individualized regional citrate anticoagulation protocol for hemodialysis: a real-world retrospective study

OBJECTIVE

To evaluate the safety and effectiveness of an individualized regional citrate anticoagulation (RCA) protocol for hemodialysis.

METHODS

In this single-center, retrospective study, blood coagulation in the extracorporeal circulation, adverse reactions, in vivo ionized calcium (iCa2+) concentrations, and the infusion dose of citrate during RCA in hemodialysis were observed in 98 patients from February 2021 to March 2022.

RESULTS

A total of 98 patients underwent RCA during hemodialysis 362 times, and blood coagulation occurred in the extracorporeal circulation 29 times. Among the 29 cases of coagulation, most of the patients exhibited hypercoagulability, and among approximately 80% of the treatments, the deviation between the actual infusion rate of citrate in the extracorporeal circulation and the theoretical value was ± 10%. After hemodialysis, pH values and bicarbonate ion (HCO3-) levels were clearly improved, and online conductivity monitoring (OCM) values and blood coagulation scores in the extracorporeal circulation were identical to those measured in similar studies.

CONCLUSION

An individualized RCA protocol for hemodialysis is safe, effective, simple, and inexpensive and can meet the needs of individualized treatment; therefore, its application is worthy of promotion.

Haemostasis patterns in patients with acute-on-chronic liver failure and acute decompensation of cirrhosis including thromboelastometric tests with and without the addition of Protac: a pilot study

BACKGROUND

Thromboelastometry is considered the best method to assesses hemostasis in liver disease. Diagnostic performance could be improved by adding protein C activators such as thrombomodulin or Protac®. We assessed changes in ROTEM parameters after the addition of Protac® in patients with acute-on-chronic liver failure (ACLF), acute decompensation (AD), and healthy individuals (HI) to define different hemostasis patterns, considering standard and velocity ROTEM parameters, and assess whether Protac® can improve the definition of the pattern.

METHODS

Pre-test, we investigated whether diluted EXTEM reagent improved the effect of Protac® on the clotting time (CT)-ratio with and without Protac®. Ten ACLF and 20 AD patients and 21 HI were included in the main study.

RESULTS

Standard EXTEM was used in the main study. INTEM CFT, INTEM A5 (inverse), and INTEM TPI (inverse) were the parameters that best differentiated liver disease from HI (ROC AUC, 0.921, 0.906, and 0.928, respectively; all P-values < 0.001). Combining INTEM CFT with EXTEM LI60-ratio only slightly improved the diagnostic performance (ROC AUC, 0.948; P < 0.001). EXTEM LI60 and INTEM maxV-t were the parameters that best differentiated between ACLF and AD patients (ROC AUC, 0.743, P = 0.033; and 0.723, P = 0.050; respectively). Combining EXTEM LI60 + INTEM maxV-t moderately improved the diagnostic performance (ROC AUC, 0.81, P < 0.001).

CONCLUSIONS

ROTEM velocity, fibrinolysis parameters and the indices calculated improve the diagnosis in combination with standard parameters (e.g., CFT and A5). Ratios calculated with and without Protac® (e.g., EXTEM LI60-ratio) only slightly increased the diagnostic performance in discriminating hemostasis patterns.

Advantages of laparoscopic hepatic hemangioma surgery in quality of life: a prospective study

BACKGROUND

Surgical intervention is the most accurate method for the treatment of hepatic hemangioma. The advantages of laparoscopic surgery on quality of life should be clarified by prospective studies.

METHODS

The sample sizes of the laparoscopic and open surgery groups were calculated based on previous retrospective literature. Intraoperative and postoperative parameters were prospectively collected and analyzed. Quality of life in both groups was predicted by a mixed linear model.

RESULTS

Sixty patients were enrolled in the laparoscopic surgery group and open surgery group. The laparoscopic group had a longer operation time (P = 0.040) and more hospitalization expenses (P = 0.001); however, the Clavien-Dindo classification and comprehensive complication index suggested a lower incidence of surgical complications in the laparoscopic group, with P values of 0.049 and 0.002, respectively. After mixed linear model prediction, between-group analysis indicated that the laparoscopic group had little impact on role-physical functioning and role-emotional functioning; in addition, within-group analysis showed a rapid recovery time on role-physical functioning and role-emotional functioning in the laparoscopic group. Quality of life in both groups recovered to the preoperative level within 1 year after the operation.

CONCLUSION

The advantages of laparoscopic hepatectomy for hepatic hemangioma were fewer postoperative complications, lower impact on quality of life and faster recovery from affected quality of life.

Fibrinogen and albumin synthesis rates in major upper abdominal surgery

Plasma fibrinogen and albumin concentrations initially decrease after abdominal surgery. On postoperative days 3-5 fibrinogen concentration returns to the preoperative level or even higher, while albumin stays low. It is not known if these altered plasma concentrations reflect changes in synthesis rate, utilization, or both. In particular a low albumin plasma concentration has often been attributed to a low synthesis rate, which is not always the case. The objective of this study was to determine fibrinogen and albumin quantitative synthesis rates in patients undergoing major upper abdominal surgery with and without intact liver size. Patients undergoing liver or pancreatic resection (n = 9+6) were studied preoperatively, on postoperative days 1 and 3-5. De novo synthesis of fibrinogen and albumin was determined; in addition, several biomarkers indicative of fibrinogen utilization were monitored. After hemihepatectomy, fibrinogen synthesis was 2-3-fold higher on postoperative day 1 than preoperatively. On postoperative days 3-5 the synthesis level was still higher than preoperatively. Following major liver resections albumin synthesis was not altered postoperatively compared to preoperative values. After pancreatic resection, on postoperative day 1 fibrinogen synthesis was 5-6-fold higher than preoperatively and albumin synthesis 1.5-fold higher. On postoperative days 3-5, synthesis levels returned to preoperative levels. Despite decreases in plasma concentrations, de novo synthesis of fibrinogen was markedly stimulated on postoperative day 1 after both hemihepatectomies and pancreatectomies, while de novo albumin synthesis remained grossly unchanged. The less pronounced changes seen following hepatectomies were possibly related to the loss of liver tissue.

Perioperative coagulation profile in major liver resection for cancer: a prospective observational study

Hepatectomy induced coagulation disturbances have been well studied over the past decade. Cumulative evidence supports the superiority of global coagulation analysis compared to conventional coagulation tests (i.e. PT or aPTT) for clinical decision making. Cancer, however, represents an acquired prothrombotic state and liver resection for cancer deserves a more thorough investigation. This prospective observational study was conducted to assess the perioperative coagulation status of patients undergoing major hepatectomies for primary or metastatic hepatic malignancy. Patients were followed up to the 10th postoperative day by serial measurements of conventional coagulation tests, plasma levels of coagulation factors and thrombin generation assay parameters. An abnormal coagulation profile was detected at presentation and included elevated FVIII levels, decreased levels of antithrombin and lag time prolongation in thrombin generation. Serial hematological data demonstrated increased vWF, FVIII, D-dimer, fibrinogen and decreased levels of natural anticoagulant proteins in the early postoperative period predisposing to a hypercoagulable state. The ratio of the anticoagulant protein C to the procoagulant FVIII was low at baseline and further declined postoperatively, indicating a prothrombotic state. Though no bleeding complications were reported, one patient experienced pulmonary embolism while under thromboprophylaxis. Overall, patients with hepatic carcinoma presenting for elective major hepatectomy may have baseline malignancy associated coagulation disturbances, aggravating the hypercoagulable state documented in the early postoperative period.

Viscoelastic testing in benign hematologic disorders: Clinical perspectives and future implications of point-of-care testing to assess hemostatic competence

Viscoelastic tests (VETs) have been used routinely for liver transplantation, cardiac surgery, and trauma, but only recently have found clinical utility in benign hematologic disorders. Therefore, guidelines for diagnosis and treatment of these disorders based on viscoelastic variables have been adapted from the existing transplant, cardiothoracic surgery, and trauma resuscitation literature. As a result, diagnostic and therapeutic strategies for benign hematologic disorders utilizing VETs are not uniform. Accordingly, even though there has been a recent increase in the utilization of VET for the diagnosis and treatment of such disorders, the literature is still in its early stages. Analysis of point-of-care viscoelastic tracings from benign hematologic disorders has the potential to allow prompt recognition of disease and to guide patient-specific intervention. Here we present a review describing the application of VETs to benign hematologic disorders.

Risk of venous thromboembolism in patients with elevated INR undergoing hepatectomy: an analysis of the American college of surgeons national surgical quality improvement program registry

BACKGROUND

Patients undergoing hepatectomy can have elevated INR and may have venous thromboembolism (VTE) prophylaxis withheld as a result. We sought to examine the association between preoperative INR elevation and VTE following hepatectomy.

METHODS

Hepatectomies captured in the American College of Surgeons National Surgical Quality Improvement Program registry between 2007 and 2016 were analyzed. Univariable and multivariable models examined the effect of incremental increases in preoperative INR on 30-day VTE, perioperative transfusion, serious morbidity, and mortality, adjusting for potential confounders.

RESULTS

We included 25,220 elective hepatectomies (62.4% partial lobectomies, 10.1% left hepatectomies, 18.6% right hepatectomies, 9.2% trisegmentectomies). The median age of the patients was 60 years and 49% were male. INR was elevated in 3089 patients (12.2%): 1.1-1.2 in 8.1%, 1.2-1.4 in 3.3%, and 1.4-2.0 in 0.9%. Incremental elevations in INR were independently associated with increasing risk for postoperative VTE [odds ratio (OR) 1.15, 95% confidence intervals 1.01-1.31], perioperative transfusion [OR 1.35 (1.28-1.43)], serious morbidity [OR 1.35 (1.28-1.43)], and mortality [OR 1.76 (1.56-1.98)].

CONCLUSION

Elevation in preoperative INR was counter-intuitively associated with increased risk of both VTE and perioperative transfusion following hepatectomy. The role of perioperative thromboprophylaxis warrants further investigation to determine optimal care in patients with elevated preoperative INR.

Infrahepatic Inferior Vena Cava Clamping does not Increase the Risk of Pulmonary Embolism Following Hepatic Resection

BACKGROUND

Infrahepatic inferior vena cava (IVC) clamping reduces central venous pressure. However, controversies remain regarding its impact on postoperative complications, particularly, the incidence of postoperative pulmonary embolism (PE). The aim of the study was to determine the impact of IVC clamping on the incidence of PE in patients undergoing hepatectomy.

METHODS

A pooled analysis of five prospective trials on patients who underwent hepatic resection over a period of 10 years was performed. Patients with infrahepatic IVC clamping were compared to patients without infrahepatic IVC clamping. Outcomes were studied by univariate and multivariate analyses.

RESULTS

Of 505 included patients, 141 patients had IVC clamping and 364 patients served as control group. The rate of postoperative PE was comparable between groups (3% vs. 3%; P = 0.762), as were postoperative morbidity (P = 0.932), bile leakage (P = 0.272), posthepatectomy hemorrhage (P = 0.095), and posthepatectomy liver failure (P = 0.605), respectively. No clinicopathological and intraoperative risk factors were found to predict the onset of PE. Subgroup analyses of patients with major hepatectomy and vascular resections confirmed no adverse perioperative outcomes to be associated with IVC clamping.

CONCLUSIONS

Infrahepatic IVC clamping does not increase the incidence of postoperative PE.

Evaluation of hemostatic abnormalities in patients who underwent major hepatobiliary pancreatic surgery using activated partial thromboplastin time-clot waveform analysis

INTRODUCTION

Bleeding after major hepatobiliary pancreatic (HBP) surgery may be serious. Although postoperative abnormality of the hemostatic system are important elements that affect bleeding, routine activated partial thromboplastin time (APTT) assessment is considered inadequate to predict massive bleeding (MB). Recently, APTT-clot waveform analysis (CWA) was reported to be useful for detecting coagulation disorders.

METHODS

APTT-CWA was performed using the ACL-TOP analyzer in 188 patients who underwent four major HBP surgeries (distal pancreatectomy, hepatectomy, subtotal stomach-preserving pancreatoduodenectomy (SSPPD), and SSPPD with combined resection and reconstruction of the portal vein) to analyze its usefulness in predicting the risk of bleeding.

RESULTS

Seventy (37.2%) patients developed MB and the incidence of MB was highest among patients who underwent hepatectomy. There were no significant differences in routine APTT, the first derivative peak (DP) time and 1/2 fibrin formation peak time between patients with MB and those without MB, throughout the postoperative course. On the other hand, the first and second DP heights were significantly lower in patients with MB than in those without MB and lowest in patients who underwent hepatectomy.

CONCLUSION

APTT-CWA was able to detect the detailed changes in the hemostatic system after major HBP surgery. The patterns of APTT-CWA after major HBP surgery differed among various surgical procedures according to invasiveness. The lower first and the second DP height, which were frequently observed in hepatectomy patients, may be useful for predicting the risk of MB.

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.

Utility of Thromboelastography to Identify Hypercoagulability in Lung Cancer Related Ischemic Stroke Patients

Lung cancer related hypercoagulability could increase the risk of ischemic stroke. Routine coagulation tests may have limited capacity in evaluating hypercoagulability. The aim of this study was to investigate the ability of thromboelastography (TEG) in the identification of hypercoagulability in patients with lung cancer and cryptogenic ischemic stroke (LCIS). Between January 2016 and December 2018, whole citrated blood from LCIS patients (n = 35) and age- and gender-matched lung cancer patients and healthy volunteers were used for TEG and routine coagulation tests. The coagulation indicator and clinical data were compared among the 3 groups. There were 27/35 (77.14%) on TEG and 18/35 (51.43%) on routine coagulation tests of LCIS patients who had evidence of hypercoagulability. The detection rate of hypercoagulability by TEG in LCIS patients was higher than routine coagulation tests (P = 0.018). Comparing with lung cancer patients and healthy controls, LCIS patients have a significantly higher maximum amplitude (MA), fibrinogen, and D-dimer. Multivariate analysis showed that D-dimer and MA were significantly associated with ischemic stroke in lung cancer patients. ROC curve showed that the area under the curve of TEG (0.790 ± 0.048, 95% CI: 0.697-0.864) was significantly higher than routine coagulation tests (0.673 ± 0.059, 95% CI: 0.572-0.763) (P = 0.04) in identifying hypercoagulability in LCIS patients. Therefore, TEG could identify hypercoagulability in LCIS patients and healthy controls. Identification of hypercoagulability in lung cancer patients by TEG may be helpful to prevent the occurrence of LCIS.

Efficacy of pro- and anticoagulant strategies in plasma of patients undergoing hepatobiliary surgery

BACKGROUND

In vitro efficacy of pro- and antihemostatic drugs is profoundly different in patients with compensated cirrhosis and in those who have cirrhosis and are critically ill.

OBJECTIVES

Here we assessed the efficacy of pro- and anticoagulant drugs in plasma of patients undergoing hepato-pancreato-biliary (HPB) surgery, which is associated with unique hemostatic changes.

METHODS

We performed in vitro analyses on blood samples of 60 patients undergoing HPB surgery and liver transplantation: 20 orthotopic liver transplantations, 20 partial hepatectomies, and 20 pylorus-preserving pancreaticoduodenectomies. We performed thrombin generation experiments before and after in vitro addition of fresh frozen plasma (FFP), prothrombin complex concentrate (PCC), recombinant factor VIIa (rFVIIa), low molecular weight heparin (LMWH), unfractionated heparin, dabigatran, and rivaroxaban.

RESULTS

We showed that patients undergoing HPB surgery are in a hypercoagulable state by thrombin generation testing. FFP and rFVIIa had minimal effects on thrombin generation, whereas PCC had a more pronounced procoagulant effect in patients compared with controls. Dabigatran showed a more pronounced anticoagulant effect in patients compared with controls, whereas rivaroxaban and LMWH had a decreased anticoagulant effect in patients.

CONCLUSION

We demonstrate profoundly altered in vitro efficacy of commonly used anticoagulants, in patients undergoing HPB surgery compared with healthy controls, which may have implications for anticoagulant dosing in the early postoperative period. In the correction of perioperative bleeding complications, PCCs appear much more potent than FFP or rFVIIa, and PCCs may require conservative dosing and caution in use in patients undergoing HPB surgery.

High D dimers and low global fibrinolysis coexist in COVID19 patients: what is going on in there?

BACKGROUD

COVID-19 coagulopathy linked to increased D-dimer levels has been associated with high mortality (Fei Z et al. in Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study. Lancet (London, England) 395(10229):1054-62, 2020). While D-dimer is accepted as a disseminated intravascular coagulation marker, rotational thromboelastometry (ROTEM) also detects fibrinolysis (Wright FL et al. in Fibrinolysis shutdown correlates to thromboembolic events in severe COVID-19 infection. J Am Coll Surg (2020). Available from https://pubmed.ncbi.nlm.nih.gov/32422349/ [cited 14 Jun 2020]; Schmitt FCF et al. in Acute fibrinolysis shutdown occurs early in septic shock and is associated with increased morbidity and mortality: results of an observational pilot study. Ann Intensive Care 9(1):19, 2019). We describe the ROTEM profile in severely ill COVID-19 patients and compare it with the standard laboratory coagulation test.

METHODS

Adult patients diagnosed with COVID-19 admitted to the ICU were prospectively enrolled after Ethics Committee approval (HCB/2020/0371). All patients received venous thromboembolism prophylaxis; those on therapeutic anticoagulation were excluded. The standard laboratory coagulation test and ROTEM were performed simultaneously at 24-48 h after ICU admission. Sequential organ failure assessment (SOFA), disseminated intravascular coagulation (DIC) and sepsis-induced coagulopathy (SIC) scores were calculated at sample collection.

RESULTS

Nineteen patients were included with median SOFA-score of 4 (2-6), DIC-score of 1 (0-3) and SIC-score of 1.8 (0.9). Median fibrinogen, D-dimer levels and platelet count were 6.2 (4.8-7.6 g/L), 1000 (600-4200 ng/ml) and 236 (136-364 10⁹/L), respectively. Clot firmness was above the normal range in the EXTEM and FIBTEM tests while clot lysis was decreased. There was no significant correlation between ROTEM or D-dimer parameters and the SOFA score.

CONCLUSION

In COVID-19 patients, the ROTEM pattern was characterized by a hypercoagulable state with decreased fibrinolytic capacity despite a paradoxical increase in D-dimer levels. We suggest that, in COVID-19 patients, the lungs could be the main source of D-dimer, while a systemic hypofibrinolytic state coexists. This hypothesis should be confirmed by future studies.

Ability of Thromboelastography to Detect Hypercoagulability: A Systematic Review and Meta-Analysis

OBJECTIVE

To review the current literature on the use of viscoelastic hemolytic assays, such as thromboelastography (TEG) and rotational thromboelastometry (ROTEM), during the perioperative period of patients and determine the ability of TEG and ROTEM to detect hypercoagulability and identify increased risk of the development of venous thromboembolism (VTE).

DATA SOURCES

PubMed, EMBASE, and Cochrane online databases were queried through February 11, 2018, by pairing the terms "thromboelastography," "viscoelastic hemostatic assays," and "rotational thromboelastometry" with "venous thromboembolism," "deep vein thrombosis," "pulmonary embolism," and "hypercoagulability."

STUDY SELECTION

Inclusion and exclusion criteria were established to determine relevance and quality of data, of which 2.54% of initially identified studies met.

DATA EXTRACTION AND SYNTHESIS

Articles and citations were reviewed for relevance by 2 independent individuals following PRISMA guidelines as well as a quality assessment of data as established by Zaza et al. In studies that separated patients postoperatively by VTE development or no VTE development, data were pooled utilizing a modified DerSimmion and Laird random effects model.

RESULTS

One thousand eight hundred ninety-three articles were assessed for eligibility, yielding 370 abstracts. Of the 370 abstracts, 35 studies were included, and of these, only 5 were included in the meta-analysis. Studies included postsurgical patients in a variety of surgical fields, encompassing a total of 8939 patients, with 717 thrombotic events reported. Elevated maximum amplitude (MA) was a statistically significant indicator of hypercoagulability across at least 1 perioperative time point in 17 (50%) of the articles reviewed, consisting of 6348 (72%) patients. The pooled mean MA value for defining hypercoagulability was greater than 66.70 mm. Using a prepublished value for hypercoagulability of 65 mm, the combined effect of MA on the development of VTE in postsurgical patients was determined to be 1.31 (95% confidence, 0.74-2.34, P = 0.175) and was 46% sensitive and 62% specific in predicting a postoperative VTE.

CONCLUSIONS

Only 1 parameter, MA, was consistently used to both define hypercoagulability and be predictive of VTE after traumatic injury and surgical intervention; however, there remains a broad variability in the definition of hypercoagulability as determined by MA and thus limits its predictive ability. In addition, when hypercoagulability was measured throughout the perioperative period, TEG consistently demonstrated hypercoagulability starting on post-op day 1 (POD1).

LEVEL OF EVIDENCE

Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

A preliminary study using rotational thromboelastometry to investigate perioperative coagulation changes and to identify hypercoagulability in obese patients undergoing total hip or knee replacement

Surgery and obesity are known risk factors for thromboembolic events due to the presence of a hypercoagulable state. Rotational thromboelastometry is a viscoelastic assay that can provide a measure of hypercoagulability via a comprehensive assessment of the coagulation process. This prospective study investigates haemostatic changes over time, presence of hypercoagulability and the association between body mass index and thromboelastometry results in patients undergoing major orthopaedic surgery. Fifty adult patients undergoing total hip or knee replacement surgery had serial thromboelastometry measures performed prior to and following surgery, and on postoperative days 1 and 3. A hypercoagulable state, defined by an ExTEM maximum clot firmness G score ≥11 dyne/cm2, was present in 28% of the patients at baseline. The mean ExTEM maximum clot firmness G score increased by an average of three units from 10 (95% confidence interval (CI) 9–11) dyne/cm2 at baseline to 13 (95% CI 13–14) dyne/cm2 on postoperative day 3, with 85% of patients having a G score ≥11 dyne/cm2. A decrease in ExTEM and InTEM clot formation time and an increase in ExTEM, InTEM and FibTEM clot amplitude at 10 minutes, alpha angle and maximum clot firmness were observed by postoperative day 3 ( P <  0.001). There was no significant difference in the mean thromboelastometry values between patients with a body mass index <35 kg/m2or ≥35 kg/m2. Although a modest association between body mass index and the ExTEM maximum clot firmness G score was observed with exploratory data analysis, further study is required in a large cohort to test the effects of confounders, validate these findings, and determine their clinical importance.

Use of Viscoelastography in Malignancy-Associated Coagulopathy and Thrombosis: A Review

The relationship between malignancy and coagulopathy is one that is well documented yet incompletely understood. Clinicians have attempted to quantify the hypercoagulable state produced in various malignancies using common coagulation tests such as prothrombin time, activated partial thromboplastin time, and platelet count; however, due to these tests' focus on individual aspects of coagulation during one specific time point, they have failed to provide clinicians the complete picture of malignancy-associated coagulopathy (MAC). Viscoelastic tests (VETs), such as thromboelastography (TEG) and rotational thromboelastometry (ROTEM), are whole blood analyses that have the advantage of providing information related to the cumulative effects of plasma clotting factors, platelets, leukocytes, and red cells during all stages of the coagulation and fibrinolytic processes. VETs have gained popularity in the care of trauma patients to objectively measure trauma-induced coagulopathy (TIC), but the utility of VETs remains yet unrealized in many other medical specialties. The authors discuss the similarities and differences between TIC and MAC, and propose a mechanism for the hypercoagulable state of MAC that revolves around the thrombomodulin-thrombin complex as it switches between activating the protein C anticoagulation pathway or the thrombin activatable fibrinolysis inhibitor coagulation pathway. Additionally, they review the current literature on the use of TEG and ROTEM in patients with various malignancies. Although limited research is currently available, early results demonstrate the utility of both TEG and ROTEM in the prediction of hypercoagulable states and thromboembolic complications in oncologic patients.

Perioperative Thromboelastometry for Adult Living Donor Liver Transplant Recipients with a Tendency to Hypercoagulability: A Prospective Observational Cohort Study

Background

Hypercoagulability can lead to serious thromboembolic events. The aim of this study was to assess the perioperative coagulation status in liver transplant recipients with a tendency to hypercoagulability.

Methods

In a prospective observational study (South African Cochrane Registry 201405000814129), 151 potential liver transplant recipients were screened for thrombophilic factors from October 2014 to June 2017, and 57 potential recipients fulfilled the inclusion criterion of presenting two or more of the following thrombophilic factors: low protein C, low protein S, low anti-thrombin, increased homocystein, increased antiphospholipid IgG/IgM antibodies, increased lupus anticoagulant, and positive Factor V Leiden mutation. Seven patients were excluded from the study because they fulfilled the exclusion criteria of cancelling the liver transplantation, oral anticoagulation, or intraoperative treatment with rFVIIa. Accordingly, 50 patients were included in the final analysis. Thromboelastometry (ROTEM) (EXTEM, INTEM and FIBTEM) and conventional coagulation tests (CCT) were performed preoperatively, during the anhepatic phase, post reperfusion, and on postoperative days (POD) 1, 3 and 7. ROTEM was used to guide blood product transfusion. Heparin was infused (60-180 U/kg/day) postoperatively for 3 days and then was replaced by low-molecular-weight heparin (20 mg/12 h).

Results

FIBTEM MCF significantly increased postoperatively above reference range on POD 7 despite normal fibrinogen plasma concentrations (p < 0.05). Both EXTEM and INTEM demonstrated significant changes with the phases of transplantation (p < 0.05), but with no intra- or postoperative hypercoagulability observed. INTEM CT (reference range, 100-240 s) normalized on POD 3 and 7 (196.1 ± 69.0 and 182.7 ± 63.8 s, respectively), despite prolonged aPTT (59.7 ± 18.7 and 46.4 ± 15.7 s, respectively; reference range, 20-40 s). Hepatic artery thrombosis (HAT) and portal vein thrombosis (PVT) were reported in 12.0% and 2.0%, respectively, mainly after critical care discharge and with high FIBTEM MCF values in 57% on POD 3 and 86% on POD 7. Receiver operating characteristics curve analyses of FIBTEM MCF were significant predictors for thromboembolic events with optimum cut-off, area under the curve and standard error on POD 3 (>23 mm, 0.779 and 0.097; p = 0.004) and POD 7 (>28 mm, 0.706 and 0.089; p = 0.020). Red blood cells (mean ± SD, 8.68 ± 5.81 units) were transfused in 76%, fresh frozen plasma (8.26 ± 4.14 units) in 62%, and cryoprecipitate (12.0 ± 3.68 units) in 28% of recipients. None of the recipients received intraoperative platelet transfusion or any postoperative transfusion. Main transplant indication was hepatitis C infection in 82%. 76% of recipients included in this highly selected patient population showed increased lupus anticoagulant, 2% increased antiphospholipid IgG/IgM antibodies, 20% increased homocysteine, 74% decreased anti-thrombin, 78% decreased protein C, 34% decreased protein S, and 24% a positive Factor V Leiden mutation. Overall 1-year survival was 62%.

Conclusion

A significant postoperative step-wise increase in FIBTEM MCF beyond the reference range was observed despite normal fibrinogen plasma concentrations, and FIBTEM MCF was a predictor for thromboembolic events in this study population, particularly after POD 3 and 7 on surgical wards when CCTs failed to detect this condition. However, the predictive value of FIBTEM MCF for postoperative HAT and PVT needs to be confirmed in a larger patient population. A ROTEM-guided anticoagulation regime needs to be developed and investigated in future studies.

Coagulation Failure in Patients With Acute-on-Chronic Liver Failure and Decompensated Cirrhosis: Beyond the International Normalized Ratio

Balanced hemostasis with hypocoagulable and hypercoagulable features may occur in acute-on-chronic liver failure (ACLF). The characteristics and prognostic impact of the coagulation profile in ACLF are unknown. Consecutive patients with ACLF (n = 36) and acute decompensation (AD; n = 24) were included. Blood samples for thromboelastometry (TE) were obtained at admission and 72 hours thereafter. The coagulation profile was evaluated in patients with and without ACLF and in those with and without systemic inflammatory response syndrome. The impact of the coagulation profile on transfusion requirements, bleeding events, and short-term survival was assessed. At admission, patients with ACLF showed more hypocoagulable characteristics compared to AD subjects, with prolonged time to initial fibrin formation and clot formation time and decreased maximum clot firmness and alpha-angle values. TE parameters worsened at 72 hours in ACLF but improved in patients with AD. Prevalence of a hypocoagulable profile (three or more TE parameters outside range) was significantly higher in patients with ACLF either at admission (61% versus 29% in AD; P = 0.03) or during follow-up. Hypocoagulability correlated with systemic inflammation and was associated with higher 28-day (45% versus 16%; P = 0.02) and 90-day (52% versus 19%; P = 0.01) mortality rates but not with transfusion requirements or bleeding. Prolonged time to initial fibrin formation (extrinsic TE assay >80 seconds) and Model for End-Stage Liver Disease score at baseline were independent predictors of 28-day mortality. Conclusion: Patients with ACLF frequently show hypocoagulable features with prolonged time to initial fibrin formation and clot formation time and reduced clot firmness; these alterations worsen after admission, correlate with systemic inflammation, and translate into higher short-term mortality; hypofibrinolysis could contribute to organ failure in ACLF.

Perioperative Thromboelastometry for Adult Living Donor Liver Transplant Recipients with a Tendency to Hypercoagulability: A Prospective Observational Cohort Study

Background

Hypercoagulability can lead to serious thromboembolic events. The aim of this study was to assess the perioperative coagulation status in liver transplant recipients with a tendency to hypercoagulability.

Methods

In a prospective observational study (South African Cochrane Registry 201405000814129), 151 potential liver transplant recipients were screened for thrombophilic factors from October 2014 to June 2017, and 57 potential recipients fulfilled the inclusion criterion of presenting two or more of the following thrombophilic factors: low protein C, low protein S, low anti-thrombin, increased homocystein, increased antiphospholipid IgG/IgM antibodies, increased lupus anticoagulant, and positive Factor V Leiden mutation. Seven patients were excluded from the study because they fulfilled the exclusion criteria of cancelling the liver transplantation, oral anticoagulation, or intraoperative treatment with rFVIIa. Accordingly, 50 patients were included in the final analysis. Thromboelastometry (ROTEM) (EXTEM, INTEM and FIBTEM) and conventional coagulation tests (CCT) were performed preoperatively, during the anhepatic phase, post reperfusion, and on postoperative days (POD) 1, 3 and 7. ROTEM was used to guide blood product transfusion. Heparin was infused (60-180 U/kg/day) postoperatively for 3 days and then was replaced by low-molecular-weight heparin (20 mg/12 h).

Results

FIBTEM MCF significantly increased postoperatively above reference range on POD 7 despite normal fibrinogen plasma concentrations (p < 0.05). Both EXTEM and INTEM demonstrated significant changes with the phases of transplantation (p < 0.05), but with no intra- or postoperative hypercoagulability observed. INTEM CT (reference range, 100-240 s) normalized on POD 3 and 7 (196.1 ± 69.0 and 182.7 ± 63.8 s, respectively), despite prolonged aPTT (59.7 ± 18.7 and 46.4 ± 15.7 s, respectively; reference range, 20-40 s). Hepatic artery thrombosis (HAT) and portal vein thrombosis (PVT) were reported in 12.0% and 2.0%, respectively, mainly after critical care discharge and with high FIBTEM MCF values in 57% on POD 3 and 86% on POD 7. Receiver operating characteristics curve analyses of FIBTEM MCF were significant predictors for thromboembolic events with optimum cut-off, area under the curve and standard error on POD 3 (>23 mm, 0.779 and 0.097; p = 0.004) and POD 7 (>28 mm, 0.706 and 0.089; p = 0.020). Red blood cells (mean ± SD, 8.68 ± 5.81 units) were transfused in 76%, fresh frozen plasma (8.26 ± 4.14 units) in 62%, and cryoprecipitate (12.0 ± 3.68 units) in 28% of recipients. None of the recipients received intraoperative platelet transfusion or any postoperative transfusion. Main transplant indication was hepatitis C infection in 82%. 76% of recipients included in this highly selected patient population showed increased lupus anticoagulant, 2% increased antiphospholipid IgG/IgM antibodies, 20% increased homocysteine, 74% decreased anti-thrombin, 78% decreased protein C, 34% decreased protein S, and 24% a positive Factor V Leiden mutation. Overall 1-year survival was 62%.

Conclusion

A significant postoperative step-wise increase in FIBTEM MCF beyond the reference range was observed despite normal fibrinogen plasma concentrations, and FIBTEM MCF was a predictor for thromboembolic events in this study population, particularly after POD 3 and 7 on surgical wards when CCTs failed to detect this condition. However, the predictive value of FIBTEM MCF for postoperative HAT and PVT needs to be confirmed in a larger patient population. A ROTEM-guided anticoagulation regime needs to be developed and investigated in future studies.

Clinical effect of enoxaparin on international normalized ratio following hepato-pancreatico-biliary and gastroesophageal resection

BACKGROUND AND OBJECTIVES

Enoxaparin inactivates factor Xa via a complex formed after binding to circulating anti-thrombin III. This mechanism is reported not to alter hemostatic measures such as clotting time, PT, or PTT. To date, no clinical trials have shown a causal relationship between the clinical/pharmacological effects of enoxaparin on international normalized ratio (INR). The aim of our study is to show the clinical effect of enoxaparin on INR.

METHODS

Patients (N = 350) were reviewed from our prospective IRB approved databases undergoing gastroesophageal or hepatobiliary surgeries. INR levels were recorded for 6 days: pre-operative to 5 days after surgery.

RESULTS

Patients (N = 289) received enoxaparin daily starting post-operative day 1, while 61 patients who did not receive enoxaparin were used as controls. The mean post-operative INR in both the 30 and 40 mg groups were both significantly higher than the mean post-operative INR of the control group (P = 0.015 and P = 0.00075, respectively); however postoperative hemoglobin levels were not significantly lower in the enoxaparin versus control.

CONCLUSION

This is the first clinical evidence of the effect of enoxaparin on INR in patients undergoing abdominal surgeries for malignancies. We demonstrate an increase in the INR for patients who received enoxaparin for post-operative VTE prophylaxis.

Utility of Viscoelastic Assays Beyond Coagulation: Can Preoperative Thrombelastography Indices Predict Tumor Histology, Nodal Disease, and Resectability in Patients Undergoing Pancreatectomy?

BACKGROUND

Hypercoagulability and malignancy have been linked since the 1860s. However, the impact of different neoplasms on multiple components of the coagulation system remains poorly understood. Thrombelastography (TEG) enables measurement of coagulation incorporating clotting through fibrinolysis. We hypothesize that specific TEG indices that are associated with hypercoagulability can be appreciated in patients with adenocarcinoma undergoing pancreatic resection.

STUDY DESIGN

Blood samples were obtained from patients undergoing pancreatic resection before surgical incision and assayed with TEG. The 4 indices of coagulation measured by TEG included in the analysis were R time, angle, maximum amplitude, and lysis at 30 minutes. Patient tumor type, nodal disease, and mass resectability were contrasted with TEG indices.

RESULTS

One hundred patients were enrolled over 18 months. The majority (63%) of patients had adenocarcinoma. Patients with adenocarcinoma had increased angle compared with other lesions (49 degrees [interquartile range {IQR} 37 to 59 degrees] vs 43 degrees [IQR 32 to 49 degrees]; p = 0.011). When excluding patients that underwent neoadjuvant therapy, patients with adenocarcinoma had shorter R times (13 minutes [IQR 9 to 16 minutes] vs 14 minutes [IQR 12 to 18 minutes]; p = 0.051), steeper angles (49 degrees [IQR 40 to 59 degrees] vs 43 degrees [IQR 32 to 49 degrees]; p = 0.010), and higher maximum amplitude (67 mm [IQR 61 to 69 mm] vs 62 mm [IQR 57 to 67 mm]; p = 0.017). Nodal disease was associated with a significantly increased angle (49 degrees [IQR 42 to 59 degrees] vs 40 degrees [IQR 32 to 50 degrees]; p = 0.002) and maximum amplitude (64 mm [IQR 61 to 69 mm] vs 62 mm [IQR 56 to 67 mm]; p = 0.017). Patients who underwent successful mass resection had longer R times (14 minutes [IQR 11 to 17 minutes] vs 10 minutes [IQR 9 to 15]; p = 0.033) and shorter angles (44 degrees [IQR 35 to 55 degrees] vs 58 degrees [IQR 45 to 66 degrees]; p = 0.025).

CONCLUSIONS

Patients with adenocarcinoma undergoing pancreatic resection have multiple TEG abnormalities consistent with hypercoagulability. These TEG outputs are associated with tumor type, nodal disease, and probability of a successful resection. The use of preoperative TEG has the potential to aid surgeon and patient discussions on anticipated disease burden and prognosis before resection.

Thromboelastometry: Relation to the severity of liver cirrhosis in patients considered for liver transplantation

The severity of liver disease is assessed by scoring systems, which include the conventional coagulation test prothrombin time-the international normalized ratio (PT-INR). However, PT-INR is not predictive of bleeding in liver disease and thromboelastometry (ROTEM) has been suggested to give a better overview of the coagulation system in these patients. It has now been suggested that coagulation as reflected by tromboelastomety may also be used for prognostic purposes. The objective of our study was to investigate whether thrombelastometry may discriminate the degree of liver insufficiency according to the scoring systems Child Pugh and Model for End-stage Liver Disease (MELD).Forty patients with chronic liver disease of different etiologies and stages were included in this observational cross-sectional study. The severity of liver disease was evaluated using the Child-Pugh score and the MELD score, and blood samples for biochemistry, conventional coagulation tests, and ROTEM were collected at the time of the final assessment for liver transplantation. Statistical comparisons for the studied parameters with scores of severity were made using Spearman correlation test and receiver-operating characteristic (ROC) curves.Spearman correlation coefficients indicated that the thromboelastometric parameters did not correlate with Child-Pugh or MELD scores. The ROC curves of the thromboelastometric parameters could not differentiate advanced stages from early stages of liver cirrhosis.Standard ROTEM cannot discriminate the stage of chronic liver disease in patients with severe chronic liver disease.

Thromboelastography demonstrates perioperative hypercoagulability in hepato-pancreato-biliary patients and supports routine administration of preoperative and early postoperative venous thromboembolism chemoprophylaxis

BACKGROUND

We hypothesized hepato-pancreato-biliary (HPB) surgery patients are more likely to be hypercoagulable than hypocoagulable, and that bleeding risks from VTE chemoprophylaxis are low. This study sought to use thromboelastography (TEG) to compare coagulation profiles with bleeding/thrombotic events in HPB patients receiving standardized perioperative chemoprophylaxis.

METHODS

Consecutive patients undergoing HPB resections by three surgeons at one institution (January 2014-December 2015) received preoperative and early postoperative VTE chemoprophylaxis and were evaluated with TEGs. Coagulation profiles were compared to bleeding/thrombotic events.

RESULTS

Of 87 total patients, 83 (95.4%) received preoperative chemoprophylaxis and 100% received it postoperatively. Median estimated blood loss was 190 ml. Only 2 (2.3%) patients received intraoperative transfusions. None required transfusions at 72-hours. Only 2 were transfused within 30 days. There was 1 (1.1%) 30-day VTE event. Of 83 preoperative TEGs, 29 (34.9%) were hypercoagulable and only 8 (9.6%) were hypocoagulable/fibrinolytic. Of 73 postoperative TEGs, 34 (46.6%) were hypercoagulable and just 8 (11.0%) were hypocoagulable/fibrinolytic. .

CONCLUSION

With routine perioperative chemoprophylaxis, both VTE and bleeding events were negligible. Perioperative TEG revealed a considerable proportion (46.6%) of HPB patients were hypercoagulable. HPB patients can receive standardized preoperative/early postoperative VTE chemoprophylaxis with effective results and minimal concern for perioperative hemorrhage.

Postoperative Liver Failure

Technical innovations in surgical techniques, anaesthesia, critical care and a spatial understanding of the intra-hepatic anatomy of the liver, have led to an increasing number of liver resections being performed all over the world. However, the number of complications directly attributed to the procedure and leading to inadequate or poor hepatic functional status in the postoperative period remains a matter of concern. There has always been a problem of arriving at a consensus in the definition of the term: postoperative liver failure (PLF). The burgeoning rate of living donor liver transplants, with lives of perfectly healthy donors involved, has mandated a consensual definition, uniform diagnosis and protocol for management of PLF. The absence of a uniform definition has led to poor comparison among various trials. PLF remains a dreaded complication in resection of the liver, with a reported incidence of up to 8 % [1], and mortality rates of up to 30–70 % have been quoted [2]. Several studies have quoted a lower incidence of PLF in eastern countries, but when it occurs the mortality is as high as in the West [3].

Effect of N-acetylcysteine on liver recovery after resection: A randomized clinical trial

BACKGROUND AND OBJECTIVES

Liver failure following hepatic resection is a multifactorial complication. In experimental studies, infusion of N-acetylcysteine (NAC) can minimize hepatic parenchymal injury.

METHODS

Patients undergoing liver resection were randomized to postoperative care with or without NAC. No blinding was performed. Overall complication rate was the primary outcome; liver failure, length of stay, and mortality were secondary outcomes. Due to safety concerns, a premature multivariate analysis was performed and included within the model randomization to NAC, preoperative ASA, extent of resection, and intraoperative vascular occlusion as factors.

RESULTS

Two hundred and six patients were randomized (110 to conventional therapy; 96 to NAC). No significant differences were noted in overall complications (32.7% and 45.7%, P = 0.06) or hepatic failure (3.6% and 5.4%, P = 0.537) between treatment groups. There was significantly more delirium within the NAC group (2.7% and 9.8%, P < 0.05) that caused early trial termination. In multivariate analysis, only randomization to NAC (OR = 2.21, 95%CI = 1.16-4.19) and extensive resections (OR = 2.28, 95%CI = 1.22-4.29) were predictive of postoperative complications.

CONCLUSIONS

Patients randomized to postoperative NAC received no benefit. There was a trend toward a higher rate of overall complications and a significantly higher rate of delirium in the NAC group. J. Surg. Oncol. 2016;114:446-450. © 2016 Wiley Periodicals, Inc.

Alterations in coagulation following major liver resection

The international normalised ratio is frequently raised in patients who have undergone major liver resection, and is assumed to represent a potential bleeding risk. However, these patients have an increased risk of venous thromboembolic events, despite conventional coagulation tests indicating hypocoagulability. This prospective, observational study of patients undergoing major hepatic resection analysed the serial changes in coagulation in the early postoperative period. Thrombin generation parameters and viscoelastic tests of coagulation (thromboelastometry) remained within normal ranges throughout the study period. Levels of the procoagulant factors II, V, VII and X initially fell, but V and X returned to or exceeded normal range by postoperative day five. Levels of factor VIII and Von Willebrand factor were significantly elevated from postoperative day one (p < 0.01). Levels of the anticoagulants, protein C and antithrombin remained significantly depressed on postoperative day five (p = 0.01). Overall, the imbalance between pro- and anticoagulant factors suggested a prothrombotic environment in the early postoperative period.

Balance between von Willebrand factor and ADAMTS13 following major partial hepatectomy

BACKGROUND

Conventional coagulation tests are frequently prolonged after liver surgery, suggesting a postoperative bleeding tendency. At the same time, thrombotic complications following partial hepatectomy (PH) are not uncommon. Little is known about changes in the platelet adhesive protein von Willebrand factor (VWF) and its cleaving protease a disintegrin and metalloprotease with a thrombospondin type 1 motif, member 13 (ADAMTS13) following a PH.

METHODS

Plasma samples were collected before and after PH and pylorus-preserving pancreaticoduodenectomy (PPPD), and from 24 healthy individuals. Plasma levels of VWF and ADAMTS13, VWF activity and VWF-dependent platelet adhesion were measured, and compared between the groups.

RESULTS

Median (i.q.r.) VWF levels increased more after PH (17 patients) than following PPPD (10), reaching the highest level on postoperative day (POD) 3 (570 (473-656) versus 354 (305-476) per cent respectively; P = 0·009). VWF levels remained raised on POD 30. A decrease in median (i.q.r.) ADAMTS13 activity was observed for both patient groups, reaching the lowest level on POD 7 (24 (16-32) versus 38 (23-66) per cent for PH and PPPD respectively; P = 0·049), and levels remained significantly reduced at POD 30. VWF activity was significantly higher on day 7 following PH compared with PPPD (median (i.q.r.) 517 (440-742) versus 385 (322-484) per cent respectively; P = 0·009), and remained increased at POD 30. VWF-dependent platelet adhesion under conditions of flow was increased until POD 30 in patients after PH and PPPD, but was more pronounced in the PH group.

CONCLUSION

There are changes in the balance between VWF and ADAMTS13 levels and activity in patients after both PH and PPPD. Changes in the VWF-ADAMTS13 axis were more pronounced and of longer duration after PH than following PPPD.

Impact of Postoperative Venous Thromboembolism on Postoperative Morbidity, Mortality, and Resource Utilization after Hepatectomy

The impact of venous thromboembolism (VTE) after hepatectomy on patient morbidity, mortality, and resource usage remains poorly defined. Better understanding of thromboembolic complications is needed to improve perioperative management and overall outcomes. About 3973 patients underwent hepatectomy within NSQIP between 2005 and 2008. Patient characteristics, operative features, and postoperative correlates of VTE were compared with identify risk factors for VTE and to assess its overall impact on postoperative outcomes.

Overall incidence of postoperative VTE was 2.4 per cent. Risk factors for postoperative VTE included older age, male gender, compromised functional status, degree of intraoperative blood transfusion, preoperative albumin level (all P < 0.05), and extent of hepatectomy ( P = 0.004). Importantly, major postoperative complications, including acute renal failure, pneumonia, sepsis, septic shock, reintubation, prolonged ventilation, cardiac arrest, and reoperation were all associated with higher rates of VTE (all P < 0.05). Operative mortality was increased among patients with VTE (6.5% vs 2.4%, P = 0.03), and patients with VTE had a 2-fold increase in hospital length of stay (12.0 vs 6.0 days, P < 0.001). Postoperative VTE remains a significant source of morbidity, mortality, and increased resource usage after hepatectomy in the United States. Routine aggressive VTE prophylaxis measures are imperative to avoid development of VTE among patients requiring hepatectomy.

Systematic review of peri-operative nutritional support for patients undergoing hepatobiliary surgery

BACKGROUND

Malnutrition is prevalent among peri-operative patients undergoing hepatobiliary surgery and is an important prognostic factor. Both hepatobiliary disease and surgical trauma significantly affects body's metabolism and environment. Therefore, it is very important for patients with liver diseases undergoing hepatobiliary surgery to receive essential nutritional support during peri-operative period.

METHODS

We summarized our clinical experience and reviewed of related literature to find the way for implementing the appropriate nutritional strategy.

RESULTS

We found after comprehensively evaluating nutrition status, function of liver and gastrointestinal tract, nutritional strategy would be selected correctly. In severe malnutrition, initiation of enteral nutrition (EN) and/or parenteral nutrition (PN) with essential or special formulae is often recommended. Especially nasojejunal feeding is indicated that early application can improve nutritional status and liver function, reduce complications and prolong survival.

CONCLUSIONS

The reasonable peri-operative nutritional support therapy can improve the effect of surgical treatment and promote the patients' recovery.

Hypercoagulability following major partial liver resection - detected by thrombomodulin-modified thrombin generation testing

BACKGROUND

Conventional coagulation tests are frequently prolonged after liver surgery, suggesting a post-operative hypocoagulability. However, these tests are unreliable for assessment of the haemostatic status in these patients. In contrast, thrombin generation testing measures the true balance between pro- and anti-coagulant factors.

AIM

To study the perioperative coagulation status in patients undergoing hemi-hepatectomy using thrombin generation assays.

METHODS

We examined thrombin generation profiles in serial plasma samples taken from seventeen patients undergoing right hemi-hepatectomy. Results were compared to ten patients undergoing pancreatic resection and twenty-four healthy volunteers. In addition, we measured conventional coagulation tests and plasma levels of several haemostatic proteins.

RESULTS

Following liver resection, the endogenous thrombin potential (ETP) slightly decreased until post-operative day 7. However, in the presence of thrombomodulin, the ETP increased [from 542 nM*min (417-694) at baseline to 845 nM*min (789-1050) on post-operative day 3] to values higher than that in healthy subjects (558 nM*min (390-680); P < 0.001), which contrasts with substantially prolonged PT levels. Normal to decreased thrombin generation was observed following pancreatic resection. Thrombin generation was only slightly affected by thrombomodulin after hemi-hepatectomy, while thrombin generation in healthy subjects decreased profoundly upon addition of thrombomodulin. This hypercoagulability following liver resection may be explained by decreased levels of protein C, S, and antithrombin and by elevated levels of factor VIII.

CONCLUSIONS

Thrombin generation in the presence of thrombomodulin revealed hypercoagulability in patients following liver resection. These results support the recently advocated restrictive use of plasma during liver resection and the exploration of more extensive use of post-operative thrombosis prophylaxis.

Efficacy of postoperative anticoagulation therapy with enoxaparin for portal vein thrombosis after hepatic resection in patients with liver cancer

BACKGROUNDS

Enoxaparin, low-molecular-weight heparin, has become a routine thromboprophylaxis in general surgery.

STUDY DESIGN

A retrospective cohort study was performed in 281 patients who underwent hepatic resections for liver cancers from 2011 to 2013. These patients were divided into two groups; an enoxaparin (-) group (n=228) and an enoxaparin (+) group (n=53). Short-term surgical results including venous thromboembolism (VTE) and portal vein thrombosis (PVT) were compared.

RESULTS

In the enoxaparin (+) group, the patients' age (65 vs. 69 years; p=0.01) and BMI (22.9 vs. 24.4; p<0.01) were significantly higher. According to the symptomatic VTE, symptomatic pulmonary embolism occurred in one patient (0.4%) in the enoxaparin (-) group, but the complication rate was not significantly different (p=0.63). The complication rate of PVT was significantly lower in the enoxaparin (+) group (10 vs. 2%; p=0.04). The independent risk factors for PVT were an operation time ≥ 300 minutes (Odds ratio 6.66) and non-treatment with enoxaparin (Odds ratio 2.49).

CONCLUSIONS

Postoperative anticoagulant therapy with enoxaparin could prevent PVT in patients who underwent hepatic resection for liver cancers.

Pharmacologic prophylaxis, postoperative INR, and risk of venous thromboembolism after hepatectomy

INTRODUCTION

Pharmacologic prophylaxis (PP) is recommended for patients undergoing general surgical procedures with at least moderate risk of venous thromboembolism (VTE). The role of PP in patients undergoing hepatectomy is controversial, however, due to concerns regarding postoperative liver dysfunction and bleeding.

METHODS

We conducted a retrospective analysis of a prospectively maintained institutional database in order to clarify the relationship between PP, postoperative INR, and risk of VTE.

RESULTS

Postoperative VTE occurred in 55 of 2,147 patients (2.6 %) and was independently associated with advanced age, higher BMI, longer procedure time, and development of a major complication, as well as higher postoperative INR (≥1.5 versus <1.5: OR 2.50, P = 0.006). Patients undergoing more extensive liver resection with higher postoperative INR were less likely to receive PP, but receipt of PP demonstrated no relationship with either VTE incidence or hemorrhagic complications.

CONCLUSIONS

In this large single-institution study, incidence of VTE was not associated with PP but was associated with higher postoperative INR, contrary to the notion that postoperative liver dysfunction is protective against VTE. The interplay between prothrombotic and antithrombotic mechanisms in posthepatectomy patients must be more completely characterized before broad recommendations can be made regarding PP use in these patients.

Long-term coagulation changes after resection of thoracoabdominal malignancies

BACKGROUND

The purpose of this study was to evaluate the long-term coagulation status of patients undergoing malignancy resection.

STUDY DESIGN

A prospective observational trial was conducted with informed consent in 52 patients (age 66 ± 10 years and 60% male) with thoracoabdominal tumors (pancreas [n = 18, 35%], esophagus [n = 13, 25%], liver [n = 7, 14%], stomach [n = 6, 12%], bile duct [n = 3, 6%], retroperitoneal [n = 3, 6%], and duodenum [n = 2, 4%]) with 6- to 12-month follow-up. Coagulation was evaluated with rotational thromboelastography (ROTEM) on whole blood and with a panel of hemostatic markers on stored plasma.

RESULTS

Maximum clot firmness (MCF) in the intrinsic, extrinsic, and fibrinogen pathways increased immediately postoperatively and then decreased by 9.2 ± 4.1 months (p < 0.05). Markers of thrombin generation (prothrombin fragment 1 + 2, fibrinolysis [D-dimer], and endothelial activation [coagulation factor VIII]) were elevated at all time points. The ROTEM pattern depended on histologic type and cancer location. All esophageal tumors were adenocarcinoma and demonstrated similar patterns to the overall population, with MCF differences over time in all 3 pathways (all p < 0.05). Regarding tumors of the pancreas or liver, there were no statistically significant differences when comparing all 3 time periods, but there were time-related differences when evaluating only primary adenocarcinomas of the liver (all p < 0.05). Three patients (6%) developed venous thromboembolism (VTE) and had decreased clot formation time, increased angle, and increased MCF (all p < 0.05).

CONCLUSIONS

Cancer patients at risk for VTE can be identified with a point-of-care ROTEM test and may benefit from additional anticoagulation. Biomarkers reflecting different functional hemostasis activity groups (fibrinolysis, thrombin generation, and endothelial activation) confirm the ongoing prothrombotic state. The ROTEM demonstrated increased hypercoagulability postoperatively, which returned to baseline in long-term follow-up. Reversal of cancer-induced hypercoagulability occurred in some patients and varied with tumor histology and location.

Pre-existing hypercoagulability in patients undergoing potentially curative cancer resection

BACKGROUND

Rotational thromboelastometry (ROTEM) is a new point-of-care test that allows a rapid and comprehensive evaluation of coagulation. We were among the first to show that ROTEM identifies baseline hypercoagulability in 40% of patients with intra-abdominal malignancies and that hypercoagulability persists for ≥1 month after resection. The purpose of this follow-up study was to confirm and extend these observations to a larger population in outpatient preoperative clinics. The hypothesis is that pre-existing hypercoagulability is present in patients undergoing surgery for malignant disease and that coagulation status varies by tumor type.

METHODS

After informed consent, preoperative blood samples were drawn from patients undergoing exploratory laparotomies for intra-abdominal malignancies and analyzed with ROTEM.

RESULTS

Eighty-two patients were enrolled, including 72 with a confirmed pathologic diagnosis and 10 age-matched controls with benign disease. The most common cancers involved the pancreas (n = 23; 32%), esophagus (n = 19; 26%), liver (n = 12; 17%), stomach (n = 7; 10%), and bile ducts (n = 5; 7%). Preoperative hypercoagulability was detected in 31% (n = 22); these patients were more likely to have lymphovascular invasion (88% vs 50%; P = .011), perineural invasion (77% vs 36%; P = .007), and stage III/IV disease (80% vs 62%; P = .039). More patients with pancreatic tumors (9/23, 39%) were hypercoagulable than with esophageal (3/19, 16%) or liver (2/13, 15%, P = .034) tumors. When only resectable malignancies were considered, clot formation was more rapid (low clot formation time, high alpha) with enhanced maximum clot strength (high maximum clot firmness) in pancreatic versus esophageal or liver cancers and in all cancers versus those with benign disease.

CONCLUSION

Preoperative hypercoagulability can be identified with ROTEM and is associated with lymphovascular/perineural invasion and advanced-staged disease in cancer. Compared with other tumor types, pancreatic adenocarcinomas have the greatest risk for hypercoagulability.

Operative terminology and post-operative management approaches applied to hepatic surgery: Trainee perspectives

Outcomes in hepatic resectional surgery (HRS) have improved as a result of advances in the understanding of hepatic anatomy, improved surgical techniques, and enhanced peri-operative management. Patients are generally cared for in specialist higher-level ward settings with multidisciplinary input during the initial post-operative period, however, greater acceptance and understanding of HRS has meant that care is transferred, usually after 24-48 h, to a standard ward environment. Surgical trainees will be presented with such patients either electively as part of a hepatobiliary firm or whilst covering the service on-call, and it is therefore important to acknowledge the key points in managing HRS patients. Understanding the applied anatomy of the liver is the key to determining the extent of resection to be undertaken. Increasingly, enhanced patient pathways exist in the post-operative setting requiring focus on the delivery of high quality analgesia, careful fluid balance, nutrition and thromboprophlaxis. Complications can occur including liver, renal and respiratory failure, hemorrhage, and sepsis, all of which require prompt recognition and management. We provide an overview of the relevant terminology applied to hepatic surgery, an approach to the post-operative management, and an aid to developing an awareness of complications so as to facilitate better confidence in this complex subgroup of general surgical patients.