Modulation of plasma fibrinogen levels in acute-phase response after hepatectomy

Hemostasis and Liver Regeneration

The liver is unique in its remarkable regenerative capacity, which enables the use of liver resection as a treatment for specific liver diseases, including removal of neoplastic liver disease. After resection, the remaining liver tissue (i.e, liver remnant) regenerates to maintain normal hepatic function. In experimental settings as well as patients, removal of up to two-thirds of the liver mass stimulates a rapid and highly coordinated process resulting in the regeneration of the remaining liver. Mechanisms controlling the initiation and termination of regeneration continue to be discovered, and many of the fundamental signaling pathways controlling the proliferation of liver parenchymal cells (i.e., hepatocytes) have been uncovered. Interestingly, while hemostatic complications (i.e., bleeding and thrombosis) are primarily thought of as a complication of surgery itself, strong evidence suggests that components of the hemostatic system are, in fact, powerful drivers of liver regeneration. This review focuses on the clinical and translational evidence supporting a link between the hemostatic system and liver regeneration, and the mechanisms whereby the hemostatic system directs liver regeneration discovered using experimental settings.

Early Morbidity and Mortality after Minimally Invasive Liver Resection for Hepatocellular Carcinoma: a Propensity-Score Matched Comparison with Open Resection

BACKGROUND

The impact of minimally invasive surgery on the short-term outcomes of patients with hepatocellular carcinoma (HCC) undergoing liver resection remains poorly defined.

METHODS

The ACS-NSQIP-targeted hepatectomy database was used to identify patients who underwent liver resection for HCC during 2014-2016. A 1:1 propensity score matching was created between patients who underwent open (OLR) vs. minimally invasive liver resection (MILR) based on age, ASA score, liver resection type, liver texture, and stage of disease. The short-term outcomes of patients undergoing OLR vs. MILR were compared.

RESULTS

Among a total cohort of 1816 patients, propensity score matching resulted in 728 liver resections: 364 (50%) OLR and 364 (50%) MILR. Overall morbidity (29% vs. 23%, P = 0.04) was greater among patients undergoing OLR compared with MILR, whereas mortality did not differ between the two approaches (2% vs 1%, P = 0.57). MILR was associated with significant reductions in hospital LOS (6 vs. 4 days, P < 0.0001) but no difference in operative time (188 vs. 171 min, P = 0.13). On multivariate logistic regression analysis, age ≥ 65 (OR:1.6, 95%CI: 1.1-2.3, P = 0.0065), ASA class ≥ 3 (OR:2.7, 95%CI: 1.5-4.7, P = 0.0003), preoperative blood transfusion (OR:9.7, 95%CI: 1.06-90.3, P = 0.04), T ≥ 3 (OR:1.9, 95%CI: 1.09-3.4, P = 0.02), operative time > 200 min (OR:1.8, 95%CI: 1.2-2.5, P = 0.0011), and OLR (OR:1.4, 95%CI: 1.002-2.03, P = 0.04) were associated with increased odds of overall morbidity.

CONCLUSIONS

MILR for HCC is associated with a shorter hospital LOS and reduced postoperative complication rates, even after controlling for important patient and clinicopathologic confounders, compared to OLR. Efforts to expand the use of MILR for hepatobiliary surgery are warranted.

A Randomized Clinical Trial of Early Enteral Nutrition to Prevent Infectious Complications in Patients With Extensive Liver Resection

After major liver resections, infections and liver insufficiency are the most common complications; these may coincide. We performed a randomized clinical trial to clarify ability of early enteral nutrition to prevent infectious complications and liver failure following major hepatectomy. We prospectively allocated consecutive patients who underwent major liver resection into either an early enteral nutrition group in which such nutrition was initiated on the first postoperative day or a nonenteral nutrition group. The primary study endpoint was rate of infectious complications. Thirty-two patients were randomly allocated to the enteral nutrition group, while 31 were assigned to the nonenteral nutrition group. No significant difference in rate of infection complications was evident between enteral (9.4%) and nonenteral group (22.6%, P = 0.184). However, complications of grade III severity or worse were significantly less frequent in the enteral (9.4%) than in the nonenteral group (32.3%, P = 0.031). Further, postoperative serum concentrations of pre-albumin and reduced-state albumin were greater in the enteral than in the nonenteral group. Early enteral nutrition did not significantly improve prevention of infectious complications, but some effectiveness in preventing severe complications and improving nutritional status was demonstrated.

[Coagulation management in patients with liver disease]

BACKGROUND

End-stage liver disease is associated with complex alterations in hemostasis. Whereas prognosis is essentially affected by life-threatening bleeding complications in some patients, others, especially those with cholestatic liver diseases, suffer from thromboembolic complications. Standard laboratory values (SLVS; prothrombin time, activated partial thrombin time, platelet count) cannot sufficiently reflect the altered balance of pro- and anticoagulatory factors. Moreover, a couple of studies indicated that SLVS are not able to predict bleeding complications in patients with acute liver failure or decompensated liver cirrhosis.

DIAGNOSIS AND THERAPY

Use of bed-side coagulation diagnostics such as thrombelastometry/-graphy, detection of thrombocyte function by multiple electrode aggregometry and selective measurement of single factors allows a targeted and causal therapy of hepatic coagulopathies especially in the context of bleeding complications or surgical interventions. In recent years, coagulation management guided by these new devices has contributed to a reduction in transfusion of allogenic blood products, which may be associated with undesirable side effects.

DISCUSSION

The current review summarizes the complex pathophysiological alterations of hemostasis associated with advanced liver insufficiency and discusses recent upcoming diagnostics and coagulation management in this patient cohort.

Proof-of-concept Studies for siRNA-mediated Gene Silencing for Coagulation Factors in Rat and Rabbit

The present study aimed at establishing feasibility of delivering short interfering RNA (siRNA) to target the coagulation cascade in rat and rabbit, two commonly used species for studying thrombosis and hemostasis. siRNAs that produced over 90% mRNA knockdown of rat plasma prekallikrein and rabbit Factor X (FX) were identified from in vitro screens. An ionizable amino lipid based lipid nanoparticle (LNP) formulation for siRNA in vivo delivery was characterized as tolerable and exerting no appreciable effect on coagulability at day 7 postdosing in both species. Both prekallikrein siRNA-LNP and FX siRNA-LNP resulted in dose-dependent and selective knockdown of target gene mRNA in the liver with maximum reduction of over 90% on day 7 following a single dose of siRNA-LNP. Knockdown of plasma prekallikrein was associated with modest clot weight reduction in the rat arteriovenous shunt thrombosis model and no increase in the cuticle bleeding time. Knockdown of FX in the rabbit was accompanied with prolongation in ex vivo clotting times. Results fit the expectations with both targets and demonstrate for the first time, the feasibility of targeting coagulation factors in rat, and, more broadly, targeting a gene of interest in rabbit, via systemic delivery of ionizable LNP formulated siRNA.

Delicate balance of bleeding and thrombosis in end-stage liver disease and liver transplantation

Liver transplantation in cirrhotic patients is accompanied by severe bleeding. Indeed, the first 100 recipients of liver allografts transplanted by Thomas E. Starzl died mainly by uncontrolled bleeding. Since then, much progress has been made as to the understanding of the pathophysiology and the treatment of hemostatic disorders in cirrhotic patients. The aim of this review is to provide a state-of-the-art overview on recent developments and treatment options for hemostatic disorder in cirrhotic patients. Patients with end-stage-liver disease (ESLD) do not suffer only from procoagulant deficiency; there is also a lack of natural anticoagulants (i.e. proteins C and S) and profibrinolytics. Conventional laboratory methods such as the determination of the international normalized ratio or the activated partial thromboplastin time cannot predict bleeding complications in these patients. Progressive diagnostic techniques reveal that cirrhotic patients have the same capacity to produce thrombin like healthy volunteers. Moreover, cirrhotic patients--and particularly those with primary biliary cirrhosis or primary sclerosing cholangitis-- are at a higher risk for developing thrombosis as compared with healthy controls. Hemostatic alterations are common in cirrhotic patients; they involve both the pro- and the anticoagulant pathways. However, this is a very delicate balance, which may be shifted to either of these pathways by different treatments thereby causing bleeding or thrombosis, respectively.

Systematic review of pathophysiological changes following hepatic resection

OBJECTIVES

Major hepatic resection is now performed frequently and with relative safety, but is accompanied by significant pathophysiological changes. The aim of this review is to describe these changes along with interventions that may help reduce the risk for adverse outcomes after major hepatic resection.

METHODS

The MEDLINE, EMBASE and CENTRAL databases were searched for relevant literature published from January 2000 to December 2011. Broad subject headings were 'hepatectomy/', 'liver function/', 'liver failure/' and 'physiology/'.

RESULTS

Predictable changes in blood biochemistry and coagulation occur following major hepatic resection and alterations from the expected path indicate a complicated course. Susceptibility to sepsis, functional renal impairment, and altered energy metabolism are important sequelae of post-resection liver failure.

CONCLUSIONS

The pathophysiology of post-resection liver failure is difficult to reverse and thus strategies aimed at prevention are key to reducing morbidity and mortality after liver surgery.

Parenteral nutrition in liver resection

Albeit a very large number of experiments have assessed the impact of various substrates on liver regeneration after partial hepatectomy, a limited number of clinical studies have evaluated artificial nutrition in liver resection patients. This is a peculiar topic because many patients do not need artificial nutrition, while several patients need it because of malnutrition and/or prolonged inability to feeding caused by complications. The optimal nutritional regimen to support liver regeneration, within other postoperative problems or complications, is not yet exactly defined. This short review addresses relevant aspects and potential developments in the issue of postoperative parenteral nutrition after liver resection.

Evaluation of Hemostatic Factors in Patients Undergoing Major Hepatic Resection and Other Major Abdominal Surgeries

The aim of this study was to evaluate the role for additional testing of coagulation in perioperative management of patients undergoing major hepatic resection. Major outcome measures were perioperative measurements of hemostatic factors (activated partial prothrombin time [aPTT], prothrombin time/international normalized ratio, fibrinogen, antithrombin-III). We conducted a prospective, single-blind study comparing hemostatic factors in patients undergoing major hepatectomy, Whipple procedures, and other gastrointestinal operations. Ninety-five consecutive patients were enrolled. No values differed significantly at baseline. Immediately postoperative, only international normalized ratio was significantly lower comparing major hepatectomy with Whipple ( P < 0.005) and other procedures ( P < 0.0032). Twenty-four hours postoperative, antithrombin-III was lower for major hepatectomy than Whipple ( P < 0.028) and others ( P < 0.0001); fibrinogen was lower compared with Whipple ( P < 0.014) and others ( P < 0.0009); international normalized ratio was lower to compared with Whipple ( P < 0.0001) and others ( P < 0.0001). aPTT measurements never differed significantly between groups at any time. Antithrombin-III and fibrinogen only correlated with international normalized ratio and aPTT for the other procedures. Additional hemostatic values beyond the standard evaluations of aPTT and international normalized ratio are needed to better assess patients undergoing major hepatic surgery.

Thromboelastography as a better indicator of hypercoagulable state after injury than prothrombin time or activated partial thromboplastin time

OBJECTIVES

To investigate the hemostatic status of critically ill, nonbleeding trauma patients. We hypothesized that a hypercoagulable state exists in patients early after severe injury and that the pattern of clotting and fibrinolysis are similar between burned and nonburn trauma patients.

MATERIALS

Patients admitted to the surgical or burn intensive care unit within 24 hours after injury were enrolled. Blood samples were drawn on days 0 through 7. Laboratory tests included prothrombin time (PT), activated partial thromboplastin time (aPTT), levels of activated factor XI, D-dimer, protein C percent activity, antithrombin III percent activity, and thromboelastography (TEG).

RESULTS

Study subjects were enrolled from April 1, 2004, to May 31, 2005, and included nonburn trauma patients (n = 33), burned patients (n = 25), and healthy (control) subjects (n = 20). Despite aggressive thromboprophylaxis, three subjects (2 burned and 1 nonburn trauma patients [6%]) had pulmonary embolism during hospitalization. Compared with controls, all patients had prolonged PT and aPTT (p < 0.05). The rate of clot formation (alpha angle) and maximal clot strength were higher for patients compared with those of controls (p < 0.05), indicating a hypercoagulable state. Injured patients also had lower protein C and antithrombin III percent activities and higher fibrinogen levels (p < 0.05 for all). Activated factor XI was elevated in 38% of patients (control subjects had undetectable levels).

DISCUSSION

Thromboelastography analysis of whole blood showed that patients were in a hypercoagulable state; this was not detected by plasma PT or aPTT. The high incidence of pulmonary embolism indicated that our current prophylaxis regimen could be improved.

Liver dysfunction and sepsis determine operative mortality after liver resection

BACKGROUND

Liver failure is the principal cause of death after hepatectomy. Its progression towards death and its relationship with sepsis are unclear. This study analysed predictors of mortality in patients with liver dysfunction and the role of sepsis in the death of these patients.

METHODS

The study focused on patients with liver dysfunction, excluding those with vascular thrombosis, after liver resection at one of two centres between 1998 and 2006.

RESULTS

Liver dysfunction occurred after 57 (4.5 per cent) of 1271 hepatectomies. Fifty-three patients without vascular thrombosis were included in the analysis, with a mortality rate of 23 per cent. Independent predictors of death were age (odds ratio (OR) 1.18 per year increase; P = 0.017), cirrhosis (OR 54.09; P = 0.004) and postoperative sepsis (OR 37.58; P = 0.005). Sepsis occurred in 15 patients (28 per cent), seven of whom died. Intestinal pathogens were isolated in 12 patients with sepsis. The risk of sepsis was significantly increased in those with surgical complications (11 of 16 versus four of 37; P < 0.001).

CONCLUSION

Sepsis plays a key role in the death of patients with liver dysfunction after hepatectomy. Early recognition and aggressive treatment of sepsis may reduce mortality.

Biochemical and clinical correlates of hypouricemia in surgical and critically ill patients

BACKGROUND

Changes in plasma uric acid concentration (UA, mumol/L) in postoperative and critical illness have pathophysiological and clinical relevance and may alter plasma antioxidant capacity. This issue is poorly understood because UA is simultaneously affected by multiple factors with impacts that have never been definitively characterized.

METHODS

Data from 1050 measurements of UA and additional variables obtained in 151 patients were processed using regression analysis.

RESULTS

The main direct correlate of UA was plasma creatinine (Cr), even in the absence of renal failure. UA was also related directly to sodium, glucose, cholesterol, albumin and other variables, and inversely to bilirubin. Postoperatively UA decreased, remaining related to preoperative UA and decreasing further with sepsis. In parenterally fed patients, UA was also inversely related to the amino acid dose. The following best fit explained three-quarters of its variability: UA=85.0(ln Cr, micromol/L)+0.6(preoperative UA)+4.3 (sodium, mmol/L)+5.4(glucose, mmol/L)-0.2(bilirubin, micromol/L)-28.9(amino acid dose, g/kg/day)-935.6; n=231, r(2)=0.74, p<0.0001. A contribution of extremely low UA to impaired plasma antioxidant capacity was suggested in severe sepsis.

CONCLUSIONS

These data show the combined effect of several factors on UA. The results may help to evaluate changes in UA in the clinical setting and pathophysiological events related to oxidative stress, and provide evidence of impaired plasma antioxidant capacity in severe sepsis.

Liver resections for hepatocellular carcinoma in chronic liver disease: experience in an Italian centre

AIM

Liver resection (LR) and transplantation are the best options for treatment of hepatocellular carcinoma (HCC). We retrospectively analysed the experience obtained with LR for HCC in chronic liver disease patients.

METHODS

Up until May 2005, 248 patients with HCC were evaluated, and 113 resected. Of these, 97 with chronic liver disease, who underwent a total of 100 resections, form the basis of this study. Age of the patients was 65.6+/-9.2 years (range 32-81, male/female 76/21). In 77 cases there was unifocal and in 23 multinodular tumour; in 61 the size of the tumours was < or =5 cm and in 39>5 cm. Limited resections were performed in 15 cases, resections of 1-2 segments in 51, and major hepatectomies in 34.

RESULTS

Blood transfusions were required in 28 cases. Three patients died postoperatively, from liver failure and/or sepsis. Seventeen patients had nonlethal complications (mostly liver dysfunction, often with signs of amplified inflammatory response, including ARDS, without evident sources of sepsis). The 5- and 10-year survival rates were 44% and 24%, respectively. Decreased survival was significantly related to increasing number of tumour nodules and degree of liver fibrosis/presence of cirrhosis, and with the expression of markers of carcinogenesis in a sub-group who received this assessment. At 5 years the rate of liver HCC recurrence was 46%, however, death was unrelated to recurrence in 41% of non-survivors.

CONCLUSIONS

Surgery for HCC achieves acceptable early and long-term results. However, the patterns affecting perioperative outcome must be better understood, and the high recurrence rate warrants further trials to assess preventive treatments after LR.

EFFECTS OF HEMORRHAGE AND LACTATED RINGER'S RESUSCITATION ON COAGULATION AND FIBRINOGEN METABOLISM IN SWINE

Hemorrhagic coagulopathy is a significant complication after traumatic injury, and much of the underlying mechanism remains unclear. We investigated the changes in fibrinogen metabolism and coagulation after a moderate hemorrhage and resuscitation. Pigs of either sex (weight, 40.9+/-0.8 kg) were anesthetized and instrumented with arterial and venous catheters and a thermodilution cardiac output catheter. Pigs were randomized into control (C; n=6), hemorrhage (H; n=6), and hemorrhage and resuscitation (H-LR; n=6) groups. Hemorrhage was induced by bleeding 35% of total blood volume for 30 min in H and H-LR groups. Resuscitation in H-LR group was performed using lactated Ringer's solution (LR) at 3 times the bled volume for 30 min. Fibrinogen metabolism was quantified using a primed constant infusion of 1-13C-phenylalanine (6 h) and d5-phenylalanine (4 h) and subsequent analysis by gas chromatograph-mass spectrometry, together with measurements of hemodynamics (hourly) and coagulation by thromboelastography (at baseline and 4 h after hemorrhage and resuscitation). Hemorrhage caused decreases in arterial pH and base excess, and an increase in arterial lactate content. Fluid resuscitation corrected these changes toward normal levels. Fibrinogen level was unchanged in C and decreased to 76%+/-4% in H and to 73%+/-3% in H-LR (both P<0.05, compared with baseline) after hemorrhage and resuscitation. Fibrinogen breakdown was increased from 3.0+/-0.4 mg kg-1 h-1 in C to 5.4+/-0.6 mg kg-1 h-1 in H and to 5.6+/-0.5 mg kg-1 h-1 in H-LR (both P<0.05, compared with control), but synthesis was unchanged. The clotting reaction time was unchanged in C and shortened to 93%+/-3% in H and to 91%+/-1% in H-LR (both P<0.05, compared with baseline). We conclude that hemorrhagic shock caused accelerated fibrinogen breakdown and coagulation. The LR resuscitation reduced tissue hypoxia indexes but did not affect the changes in fibrinogen metabolism and coagulation from hemorrhage. Thus, effective treatment of hemorrhage should include combining standard-of-care resuscitation with interventions to correct alterations in coagulation.

The relationship between albumin, other plasma proteins and variables, and age in the acute phase response after liver resection in man

A large series of plasma albumin (ALB, g/dl) and simultaneous blood and clinical measurements were prospectively performed on 92 liver resection patients, and processed to assess the correlations between ALB, other plasma proteins, additional variables and clinical events. The measurements were performed preoperatively and at postoperative day 1, 3 and 7 in all patients, and subsequently only in those who developed complications or died. In patients who recovered normally ALB was 4.3 +/- 0.4 g/dl (mean +/- SD) preoperatively, 3.7 +/- 0.7 at day 1 and 3, and 3.9 +/- 0.4 at day 7. In patients with complications its decrease was more prolonged. In non-survivors it was 3.4 +/- 0.4 preoperatively, 3.0 +/- 0.4 at day 1, and then decreased further. Regression analysis showed direct correlations between ALB and pseudo-cholinesterase (CHE, U/l, nv 5300-13000), cholesterol (CHOL, mg/dl), iron binding capacity (IBC, mg/dl), prothrombin activity (PA, % of standard reference) and fibrinogen, an inverse correlation with blood urea nitrogen (BUN, mg/dl) for any given creatinine level (CREAT, mg/dl), and weaker direct correlations with hematocrit, other variables and dose of exogenous albumin. An inverse relationship found between ALB and age (AGE, years) became postoperatively (POSTOP) also a function of outcome, showing larger age-related decreases in ALB associated with complications (COMPL: sepsis, liver insufficiency) or death (DEATH). Main overall correlations: CHE = 287.4(2.014)(ALB), r = 0.73; CHOL = 16.5(1.610)(ALB) (1.001)(ALKPH), r = 0.71; IBC = 68.6(1.391)(ALB), r = 0.64; PA = 13.8 + 16.0(ALB), r = 0.51; BUN = 21.3 + 20.2(CREAT) - 6.2(ALB), r = 0.91; ALB = 5.0-0.013(AGE) - {0.5 + 0.003(AGE)( COMPL ) + 0.012(AGE)( DEATH )}( POSTOP ), r = 0.74 [p < 0.001 for each regression and each coefficient; ALKPH = alkaline phosphatase, U/l, nv 98-279, independent determinant of CHOL; discontinuous variables in italics label the change in regression slope or intercept associated with the corresponding condition]. These results suggest that altered albumin synthesis (or altered synthesis unable to compensate for albumin loss, catabolism or redistribution) is an important determinant of hypoalbuminemia after hepatectomy. The correlations with age and postoperative outcome support the concept that hypoalbuminemia is a marker of pathophysiologic frailty associated with increasing age, and amplified by the challenges of postoperative illness.