Liver maximum capacity (LiMAx) test as a helpful prognostic tool in acute liver failure with sepsis: a case report

Obeticholic Acid Improves Cholestasis, Liver Fibrosis, and Liver Function in Patients with Primary Biliary Cholangitis with Inadequate Response to Ursodeoxycholic Acid

Background and Aims: Primary biliary cholangitis (PBC) leads to the slow, progressive destruction of the small bile ducts with consecutive cholestasis and intrahepatic cholangitis. If this disease remains untreated, liver parenchyma will be damaged resulting in fibrosis and end-stage liver disease with the need for transplantation. The approval of the Farnesoid X receptor agonist obeticholic acid (Ocaliva; OCA) in early 2017 expanded the drug therapy options of PBC, which previously consisted primarily of the administration of ursodeoxycholic acid (UDCA). Patients and Methods: Included in our prospective pilot study were 16 patients with a confirmed diagnosis of PBC who were treated with an add-on therapy with OCA (5 mg/d). None of the patients had an overlap to autoimmune hepatitis. Patients were investigated between 09/2022 and 09/2023. Results: The majority of patients was female (15/16, 93.75%), and the mean age was 57.63 ± 9.59 (43-77) years. OCA treatment led to a statistically significant decrease in aspartate aminotransferase (AST; AST baseline: 38.50 [26.25; 50.00] IU/L vs. AST 6-month follow-up: 23.50 [21.50; 44.25] IU/L, p = 0.0012), alanine aminotransferase (ALT; ALT baseline: 55.50 [28.75; 97.00] IU/L vs. ALT 6-month follow-up: 36.50 [28.00; 57.25] IU/L, p = 0.0035), and gamma-glutamyl transferase (GGT; GGT baseline: 168.00 [100.30; 328.50] IU/L vs. GGT 6-month follow-up: 88.00 [44.50; 259.80] IU/L, p = 0.0063), while the decrease in alkaline phosphatase (AP) was not statistically significant (AP baseline: 197.00 [170.00; 253.30] IU/L vs. AP 6-month follow-up: 196.00 [134.00; 227.00] IU/L, p = 0.0915). In addition, liver stiffness measurement (LSM) showed a statistically significant decrease after six months of treatment with OCA (LSM baseline: 7.85 [5.55; 10.13] kPa vs. LSM 6-month follow-up: 5.95 [4.55; 8.225] kPa, p = 0.0001). However, the increase in enzymatic liver function measured by LiMAx failed to reach statistical significance, but showed a positive trend (LiMAx baseline: 402.50 [341.50; 469.80] μg/kg/h vs. LiMAx 6-month follow-up: 452.50 [412.50; 562.00] μg/kg/h, p = 0.0625). In none of our patients did therapy with obeticholic acid have to be stopped due to pruritus or poor tolerability. Conclusions: In patients with PBC without adequate response to UDCA, OCA is a promising alternative, which in our group of 16 patients led to a significant improvement of liver enzymes, the amelioration of liver fibrosis, and an increase in liver function capacity in a short-term clinical course.

Isoflurane, like sepsis, decreases CYP1A2 liver enzyme activity in intensive care patients: a clinical study and network model

PURPOSE

Liver function of intensive care patients is routinely monitored by static blood pathology. For specific indications, liver specific cytochrome activity may be measured by the commercially available maximum liver function capacity (LiMAx) test via quantification of the cytochrome P450 1A2 (CYP1A2) dependent C-methacetin metabolism. Sedation with the volatile anesthetic isoflurane was suspected to abrogate the correlation of LiMAx test with global liver function. We hypothesized that isoflurane has a CYP1A2-activity and LiMAx test result decreasing effect.

METHODS

In this monocentric, observational clinical study previously liver healthy intensive care patients, scheduled to be changed from propofol to isoflurane sedation, were enrolled. LiMAx testing was done before, during and after termination of isoflurane sedation.

RESULTS

The mean LiMAx value decreased during isoflurane sedation. Septic patients (n = 11) exhibited lower LiMAx values compared to non-septic patients (n = 11) at all time points. LiMAx values decreased with isoflurane from 140 ± 82 to 30 ± 34 µg kg-1 h-1 in the septic group and from 253 ± 92 to 147 ± 131 µg kg-1 h-1 in the non-septic group while laboratory markers did not imply significant hepatic impairment. Lactate increased during isoflurane inhalation without clinical consequence.

CONCLUSION

Sepsis and isoflurane have independently demonstrated an effect on reducing the hepatic CYP1A2-activity. A network model was constructed that could explain the mechanism through the influence of isoflurane on hypoxia inducible factor (HIF-1α) by upregulation of the hypoxia-inducible pathway and the downregulation of CYP1A2-activity via the ligand-inducible pathway. Thus, the increased anaerobic metabolism may result in lactate accumulation. The influence of isoflurane sedation on the validated correlation of global liver function with CYP1A2-activity measured by LiMAx testing needs to be investigated in more detail.

Liver Function-How to Screen and to Diagnose: Insights from Personal Experiences, Controlled Clinical Studies and Future Perspectives

Acute and chronic liver disease is a relevant problem worldwide. Liver function plays a crucial role in the course of liver diseases not only in estimating prognosis but also with regard to therapeutic interventions. Within this review, we discuss and evaluate different tools from screening to diagnosis and give insights from personal experiences, controlled clinical studies and future perspectives. Finally, we offer our novel diagnostic algorithm to screen patients with presumptive acute or chronic liver disease in the daily clinical routine.

Immunomodulation by Hemoadsorption—Changes in Hepatic Biotransformation Capacity in Sepsis and Septic Shock: A Prospective Study

Background: Sepsis is often associated with liver dysfunction, which is an indicator of poor outcomes. Specific diagnostic tools that detect hepatic dysfunction in its early stages are scarce. So far, the immune modulatory effects of hemoadsorption with CytoSorb^® on liver function are unclear. Method: We assessed the hepatic function by using the dynamic LiMAx^® test and biochemical parameters in 21 patients with sepsis or septic shock receiving CytoSorb^® in a prospective, observational study. Points of measurement: T₁: diagnosis of sepsis or septic shock; T₂ and T₃: 24 h and 48 h after the start of CytoSorb^®; T₄: 24 h after termination of CytoSorb^®. Results: The hepatic biotransformation capacity measured by LiMAx^® was severely impaired in up to 95 % of patients. Despite a rapid shock reversal under CytoSorb^®, a significant improvement in LiMAx^® values appeared from T₃ to T₄. This decline and recovery of liver function were not reflected by common parameters of hepatic metabolism that remained mostly within the normal range. Conclusions: Hepatic dysfunction can effectively and safely be diagnosed with LiMAx^® in ventilated ICU patients under CytoSorb^®. Various static liver parameters are of limited use since they do not adequately reflect hepatic dysfunction and impaired hepatic metabolism.

The LiMAx Test as Selection Criteria in Minimally Invasive Liver Surgery

BACKGROUND

Liver failure is a crucial predictor for relevant morbidity and mortality after hepatic surgery. Hence, a good patient selection is mandatory. We use the LiMAx test for patient selection for major or minor liver resections in robotic and laparoscopic liver surgery and share our experience here.

PATIENTS AND METHODS

We identified patients in the Magdeburg registry of minimally invasive liver surgery (MD-MILS) who underwent robotic or laparoscopic minor or major liver surgery and received a LiMAx test for preoperative evaluation of the liver function. This cohort was divided in two groups: patients with normal (LiMAx normal) and decreased (LiMAx decreased) liver function measured by the LiMAx test.

RESULTS

Forty patients were selected from the MD-MILS regarding the selection criteria (LiMAx normal, n = 22 and LiMAx decreased, n = 18). Significantly more major liver resections were performed in the LiMAx normal vs. the LiMAx decreased group (13 vs. 2; p = 0.003). Hence, the mean operation time was significantly longer in the LiMAx normal vs. the LiMAx decreased group (356.6 vs. 228.1 min; p = 0.003) and the intraoperative blood transfusion significantly higher in the LiMAx normal vs. the LiMAx decreased group (8 vs. 1; p = 0.027). There was no significant difference between the LiMAx groups regarding the length of hospital stay, intraoperative blood loss, liver surgery related morbidity or mortality, and resection margin status.

CONCLUSION

The LiMAx test is a helpful and reliable tool to precisely determine the liver function capacity. It aids in accurate patient selection for major or minor liver resections in minimally invasive liver surgery, which consequently serves to improve patients' safety. In this way, liver resections can be performed safely, even in patients with reduced liver function, without negatively affecting morbidity, mortality and the resection margin status, which is an important predictive oncological factor.

Profound decrease of liver maximum function capacity test of isoflurane sedated patients: A report of three cases

LiMAx 13C-methacetin breath test results should be interpreted with caution in patients sedated with isoflurane.

Liver failure-future challenges and remaining questions

This review compiles the current state of controversial aspects of liver failure and outlines future challenges. The definition of acute liver failure (ALF) is widely accepted and implies no previous liver injury whereas the term "acute-on-chronic liver failure" remains contested. We will promote a concept, in which we differentiate three types of liver failure: ALF, acute-on-chronic liver failure (AOCLF) and acute-on-liver-cirrhosis (AOCi). The mechanistical insights into the coagulation system in patients with hepatic insufficiency have increased fundamentally in the past 10 years. Therefore, we follow now the concept of the so-called rebalanced hemostasis. This lower-level equilibrium arises from the fact that most coagulation factors and inhibitors are synthesized within the liver. We will demonstrate the advantage of viscoelastic test methods, which can assess the coagulation situation in patients with liver insufficiency much more precisely than conventional global coagulation tests. The therapeutic option of emergency liver transplantation (ELT) has significantly improved the prognosis of patients with ALF. However, limiting factors such as shortage of organs increase more and more the need for reliable prognostic markers. Due to a better understanding of the regenerative process during ALF new survival markers and prognostic tools have been emerging on the horizon in the last decade. Therefore, we will describe the current state of research in this field.

Pericarditis Caused by Enterococcus faecium with Acute Liver Failure Treated by a Multifaceted Approach including Antimicrobials and Hemoadsorption

Background

Sepsis and septic shock are still life-threatening diseases with a high mortality rate. We report a complex case of peritonitis with pericarditis and acute liver failure caused by septic shock. Potentially hepatotoxic antibiotic therapy levels were monitored using the liver maximum capacity (LiMAx®) test, and standard treatment was supplemented by adjunctive hemoadsorption with CytoSorb®. Case Presentation. The case features a 29-year-old woman with a history of Crohn's disease and cachexia. Peritonitis caused by Enterococcus faecium was diagnosed later due to an ileum perforation. The hematogenic spread led to pericarditis. In addition, sepsis-related acute liver failure complicated antimicrobial therapy further. The combination of standard therapy, anti-infective medication, and blood purification was associated with inflammation control, hemodynamic stabilization, and a concomitant decrease in vasopressor support. An efficient, sustained reduction in plasma bilirubin levels was achieved while maintaining liver function.

Conclusions

This case shows how complex infectious diseases with an atypical infectious focus resulting in septic shock can be successfully treated. A combination of antimicrobial (tigecycline and caspofungin) and long-term adjunctive hemoadsorption therapy was administered while hepatotoxic antibiotic medication was monitored by liver function testing.

Pharmacokinetics of tigecycline in critically ill patients with liver failure defined by maximal liver function capacity test (LiMAx)

BACKGROUND

In critically ill patients, tigecycline (TGC) remains an important therapeutic option due to its efficacy against multiresistant Gram-positive and Gram-negative bacteria. TGC is metabolized and eliminated predominantly by the liver. Critical illness-induced liver failure may have a profound impact on the pharmacokinetic of TGC. In the present study, we aimed to establish a link between the degree of liver dysfunction and TGC plasma concentration using the novel maximum liver function capacity (LiMAx) test, as a dynamic liver function test.

MATERIALS/METHODS

The prospective study included 33 patients from a surgical ICU with the clinical indication for antibiotic therapy with TGC. The patients received 100 mg loading dose of TGC followed by intermittent standard doses of 50 mg q12. Blood samples for TGC plasma concentration were collected at 0.3, 2, 5, 8 and 11.5 h in a steady-state condition after at least 36 h post-standard dosage. The results were analyzed by means of a high-performance liquid chromatography (HPLC) method. Within the same day, the LiMAx test was carried out and routine blood parameters were measured.

RESULTS

Peak plasma concentrations of TGC were significantly higher in patients with severe liver failure (LiMAx < 100 µg/kg/h) when compared to patients with normal liver function (LiMAx > 300 µg/kg/h). The pharmacokinetic curves revealed higher values in severe liver failure at any measured point. Moreover, LiMAx and total bilirubin were the only liver-related parameters that correlated with TGC C_max.

CONCLUSIONS

The present study demonstrates a high variability of TGC plasma concentrations in critically ill patients. The results show a significant correlation between the degree of liver dysfunction, measured by the LiMAx test, and TGC C_max. LiMAx test may be a helpful tool beyond others for adjusting the required dosage of hepatic metabolized antibiotics in critically ill patients. Trial registry DRKS-German clinical trials register; Trial registration number: DRKS00008888; Date of registration: 07-17-2015; Date of enrolment of the first participant to the trial: 12-10-2015.

A novel variant of the 13C-methacetin liver function breath test that eliminates the confounding effect of individual differences in systemic CO2 kinetics

The principle of dynamic liver function breath tests is founded on the administration of a ¹³C-labeled drug and subsequent monitoring of ¹³CO₂ in the breath, quantified as time series delta over natural baseline ¹³CO₂ (DOB) liberated from the drug during hepatic CYP-dependent detoxification. One confounding factor limiting the diagnostic value of such tests is that only a fraction of the liberated ¹³CO₂ is immediately exhaled, while another fraction is taken up by body compartments from which it returns with delay to the plasma. The aims of this study were to establish a novel variant of the methacetin-based breath test LiMAx that allows to estimate and to eliminate the confounding effect of systemic ¹³CO₂ distribution on the DOB curve and thus enables a more reliable assessment of the hepatic detoxification capacity compared with the conventional LiMAx test. We designed a new test variant (named "2DOB") consisting of two consecutive phases. Phase 1 is initiated by the intravenous administration of ¹³C-bicarbonate. Phase 2 starts about 30 min later with the intravenous administration of the ¹³C-labelled test drug. Using compartment modelling, the resulting 2-phasic DOB curve yields the rate constants for the irreversible elimination and the reversible exchange of plasma ¹³CO₂ with body compartments (phase 1) and for the detoxification and exchange of the drug with body compartments (phase 2). We carried out the 2DOB test with the test drug ¹³C-methacetin in 16 subjects with chronic liver pathologies and 22 normal subjects, who also underwent the conventional LiMAx test. Individual differences in the systemic CO₂ kinetics can lead to deviations up to a factor of 2 in the maximum of DOB curves (coefficient of variation CV ≈ 0.2) which, in particular, may hamper the discrimination between subjects with normal or mildly impaired detoxification capacities. The novel test revealed that a significant portion of the drug is not immediately metabolized, but transiently taken up into a storage compartment. Intriguingly, not only the hepatic detoxification rate but also the storage capacity of the drug, turned out to be indicative for a normal liver function. We thus used both parameters to define a scoring function which yielded an excellent disease classification (AUC = 0.95) and a high correlation with the MELD score (R_Spearman = 0.92). The novel test variant 2DOB promises a significant improvement in the assessment of impaired hepatic detoxification capacity. The suitability of the test for the reliable characterization of the natural history of chronic liver diseases (fatty liver-fibrosis-cirrhosis) has to be assessed in further studies.

Dosing of Antimycotic Treatment in Sepsis-Induced Liver Dysfunction by Functional Liver Testing with LiMAx®

Background

Sepsis-treatment is one of the major challenges in our time. Especially fungal infections play an important role in patient's morbidity and mortality. In patients with septic shock, liver function is often significantly impaired and therefore also hepatic drug metabolism is altered.

Case Presentation

We report about a 56-year-old man suffering from invasive fungal infection with multiorgan failure, after complicated medical history due to symptomatic infrarenal aortic aneurysm. On the first postoperative day, a CT scan was undertaken due to massive back pain showing renal infarction on both sides. As qualitative and quantitative renal function was impaired, hemodialysis was started immediately. Subsequently, the patient developed a compartment syndrome of the left leg and underwent fasciotomy. On admission day 7, the patient presented with hematochezia leading to colonoscopy. During this procedure, an ischemic colitis was observed. As conservative treatment failed, the patient underwent Hartmann's procedure due to progredient ischemia followed by a worsening of the clinical status due to sepsis. The patient suffered from an invasive fungal infection with Candida spp. and Aspergillus spp. Systemic antifungal treatment was initiated. Although azoles are considered first-line treatment in these cases we chose the echinocandin caspofungin for its presumed lower impact on liver function compared to azoles like voriconazole or Amphothericin B. However, caspofungin is also metabolised in the liver and can cause hepatotoxic effects. Therefore we measured metabolic liver function capacity using LiMAx®and adapted the patient's dose of caspofungin to the evaluated liver function capacity to achieve an effective and liver-protective level of the active drug. After complicated medical history with 15 weeks of hospital stay, the patient was discharged in general good condition.

Conclusions

To our knowledge, this is the first report that relates antimycotic drug dosing to a functional liver test. We provide a new approach for sepsis treatment considering liver function capacity to optimize dosage of hepatically metabolised drugs with potential hepatotoxic effects.

[Hepatic dysfunction in patients with cardiogenic shock]

Cardiogenic shock is a life-threatening condition that is frequently associated with acute hepatic dysfunction. Due to low cardiac output resulting in end-organ hypoperfusion and hypoxia, different types of liver dysfunction can develop, such as hypoxic hepatitis or acute liver failure. A very serious and late sequela is the secondary sclerosing cholangitis in critically patients. Clinical management of acute hepatic dysfunction involves the stabilization of cardiac output to improve hepatic perfusion and the optimization of liver oxygenation. However, despite maximum efforts in supportive treatment, the outcome of patients with cardiogenic shock and concomitant hepatic dysfunction remains poor.

Enzymatic liver function measured by LiMAx - a reliable diagnostic and prognostic tool in chronic liver disease

Chronic liver disease (CLD) is a major cause of morbidity and mortality worldwide. Non-invasive assessment of hepatic disease severity represents a relevant issue to further improve clinical management and therapeutic treatment. We retrospectively compared the diagnostic and prognostic performance of different non-invasive tools (LiMAx, transient elastography (TE), and biomarkers) in detecting different severity stages during the course of CLD. Patients were divided into four groups based on clinical parameters: (1) patients without CLD (control group), (2) patients suffering from CLD without having cirrhosis, (3) patients with CLD and compensated cirrhosis, and finally, (4) patients with CLD and decompensated cirrhosis. Patients with acute liver failure were excluded from the analysis. A total of 464 patients who underwent LiMAx measurement at the University Clinic of Essen between 10/2016 and 11/2017 were included in this study. Distribution of the different groups were n = 72 patients for group 1, n = 134 patients for group 2, n = 160 patients for group 3, and n = 98 patients for group 4, respectively. Median LiMAx values significantly declined with respect to increasing degree of CLD: (1) 510 µg/h/kg, (2) 390 µg/h/kg, (3) 264 µg/h/kg, and (4) 151 µg/h/kg (p < 0.001). When comparing the diagnostic accuracy of the LiMAx test in detecting patients with presence of cirrhosis (groups 1 and 2 vs. groups 3 and 4), an AUROC of 0.942 was found (cut-off 322 µg/h/kg, sensitivity 86.1%, specificity 91.3%, p < 0.0001). LiMAx was superior to TE and serum biomarkers in predicting patients’ outcome by 90-day mortality (AUROC 0.811, p < 0.001). Enzymatic liver function measured by LiMAx was closely associated with different severity stages of CLD and was a reliable diagnostic and prognostic tool with an accuracy comparable to current standard methods.