Hepatorenal Acute Kidney Injury and the Importance of Raising Mean Arterial Pressure

Postoperative Dipping Patterns of Mean Arterial Pressure and Mortality After Coronary Artery Bypass Grafting

Blood pressure dipping patterns have long been considered to be associated with adverse events. We aimed to investigate whether dipping patterns of postoperative MAP were related to 90-day and hospital mortality in patients undergoing CABG. Four thousand three hundred ninety-one patients were classified into extreme dippers (night-to-day ratio of MAP ≤ 0.8), dippers (0.8 < night-to-day ratio of MAP ≤ 0.9), non-dippers (0.9 < night-to-day ratio of MAP ≤ 1), and reverse dippers (> 1). Compared with non-dippers, reverse dippers were at a higher risk of 90-day mortality (aHR = 1.58; 95% CI, 1.10-2.27) and hospital mortality (aOR = 1.97; 95% CI, 1.12-3.47). A significant interaction was observed between hypertension and dipping patterns (P for interaction = 0.02), with a significant increased risk of 90-day mortality in non-hypertensive reverse dippers (aHR = 1.90; 95% CI, 1.17-3.07) but not in hypertensive reverse dippers (aHR = 1.26; 95% CI, 0.73-2.19).

Role of albumin infusion in cirrhosis-associated complications

Cirrhosis is an advanced-stage liver disease that occurs due to persistent physiological insults such as excessive alcohol consumption, infections, or toxicity. It is characterised by scar tissue formation, portal hypertension, and ascites (accumulation of fluid in the abdominal cavity) in decompensated cirrhosis. This review evaluates how albumin infusion ameliorates cirrhosis-associated complications. Since albumin is an oncotic plasma protein, albumin infusion allows movement of water into the intravascular space, aids with fluid resuscitation, and thereby contributes to resolving cirrhosis-induced hypovolemia (loss of extracellular fluid) seen in ascites. Thus, albumin infusion helps prevent paracentesis-induced circulatory dysfunction, a complication that occurs when treating ascites. When cirrhosis advances, other complications such as spontaneous bacterial peritonitis and hepatorenal syndrome can manifest. Infused albumin helps mitigate these by exhibiting plasma expansion, antioxidant, and anti-inflammatory functions. In hepatic encephalopathy, albumin infusion is thought to improve cognitive function by reducing ammonia concentration in blood and thereby tackle cirrhosis-induced hepatocyte malfunction in ammonia clearance. Infused albumin can also exhibit protective effects by binding to the cirrhosis-induced proinflammatory cytokines TNFα and IL6. While albumin administration has shown to prolong overall survival of cirrhotic patients with ascites in the ANSWER trial, the ATTIRE and MACHT trials have shown either no effect or limitations such as development of pulmonary oedema and multiorgan failure.  Thus, albumin infusion is not a generic treatment option for all cirrhosis patients. Interestingly, cirrhosis-induced structural alterations in native albumin (which lead to formation of different albumin isoforms) can be used as prognostic biomarkers because specific albumin isoforms indicate certain complications of decompensated cirrhosis.

The association between mean arterial pressure and acute kidney injury reversal among patients with decompensated cirrhosis

BACKGROUND AND AIMS

This study informs how mean arterial pressure (MAP) impacts acute kidney injury (AKI) recovery among all patients hospitalized with cirrhosis, regardless of etiology.

APPROACH AND RESULTS

We identified incident AKI episodes among subjects in our cohort of patients with decompensated cirrhosis. AKI was defined as a ≥50% increase in creatinine from an outpatient baseline (≥7 days prior) that required hospitalization. Linear mixed effects models were completed to determine the impact between AKI recovery, MAP, and time. To determine the impact of MAP on AKI reversal, we completed time-dependent Cox regression models with time beginning at the time of peak creatinine and ending at death, discharge, or AKI reversal, among those hospitalized with AKI and those with persistent AKI (≥48 h) We identified 702 hospitalized patients with cirrhosis with AKI. We found those with AKI reversal had, on average, higher MAP (2.1 mm Hg, p <0.05) and a greater increase in MAP over time (0.1 mm Hg per hour, p <0.001). Among all 702 hospitalized patients with AKI and adjusted for confounders, each 5 mm Hg increase in MAP was associated with 1.07× the hazard of AKI reversal ( p <0.01). Similarly, among those with persistent AKI after adjusting for confounders, each 5 mm Hg increase in MAP was associated with a 1.19× greater likelihood of AKI reversal ( p <0.001).

DISCUSSION

Our data demonstrate that MAP significantly increases the likelihood of AKI recovery regardless of severity or injury or AKI phenotype. We believe these data highlight the importance of MAP as a clinical tool to promote kidney function recovery among patients with cirrhosis hospitalized with AKI.

Acute kidney injury in patients with cirrhosis: Acute Disease Quality Initiative (ADQI) and International Club of Ascites (ICA) joint multidisciplinary consensus meeting

Patients with cirrhosis are prone to developing acute kidney injury (AKI), a complication associated with a markedly increased in-hospital morbidity and mortality, along with a risk of progression to chronic kidney disease. Whereas patients with cirrhosis are at increased risk of developing any phenotype of AKI, hepatorenal syndrome (HRS), a specific form of AKI (HRS-AKI) in patients with advanced cirrhosis and ascites, carries an especially high mortality risk. Early recognition of HRS-AKI is crucial since administration of splanchnic vasoconstrictors may reverse the AKI and serve as a bridge to liver transplantation, the only curative option. In 2023, a joint meeting of the International Club of Ascites (ICA) and the Acute Disease Quality Initiative (ADQI) was convened to develop new diagnostic criteria for HRS-AKI, to provide graded recommendations for the work-up, management and post-discharge follow-up of patients with cirrhosis and AKI, and to highlight priorities for further research.

Improving Outcomes in Hepatorenal Syndrome-Acute Kidney Injury With Early Diagnoses and Implementation of Approved Treatment Regimens

Decompensated cirrhosis, defined by the overt manifestations of liver failure and portal hypertension (eg, ascites, hepatic encephalopathy, variceal bleeding), is the inflection point associated with increased morbidity and mortality in chronic liver disease. Acute kidney injury in the setting of cirrhosis (hepatorenal syndrome-acute kidney injury [HRS-AKI]) is a severe and often fatal complication. The goals of treatment of HRS-AKI are to reverse renal failure and prolong survival in these critically ill patients or perhaps to allow the transplant team to complete the pretransplant evaluation and bridge the patient to transplant. Historically, in the United States, standard-of-care treatments for HRS-AKI were chosen by default despite lack of data, off-label use, and suboptimal results. Terlipressin represents the first drug in the United States indicated for the treatment of HRS-AKI. This review provides an up-to-date overview of HRS-AKI, discusses terlipressin and how to incorporate this new treatment into patient care and streamline society guidelines on HRS diagnosis and treatment in a practical way for clinical use, and concludes with a sample order set that highlights the recommendations discussed throughout the supplement.

Improving the Management of Hepatorenal Syndrome-Acute Kidney Injury Using an Updated Guidance and a New Treatment Paradigm

Cirrhosis, or advanced scarring of the liver, represents the end stage of chronic liver disease and is associated with high morbidity and mortality. Hepatorenal syndrome-acute kidney injury (HRS -AKI), a condition causing functional and progressive kidney failure, is a complication of cirrhosis that contributes to its high mortality rate. In the United States, the standard-of-care treatments for HRS -AKI have historically been suboptimal. Recently, terlipressin became the first drug approved for HRS -AKI in the United States, and the American Association for the Study of Liver Diseases updated its guidance document on HRS diagnosis and management. Clinical practice guidelines and guidance documents have a variable effect on physician behavior owing to a lack of awareness, familiarity, and education. The imple mentation of standardized order sets can improve guidance adherence and the quality of care delivered by encouraging data-driven treatment administration, especially for new therapies. This review seeks to facilitate improvements in the management of HRS -AKI by discussing early HRS -AKI interventions, which will streamline diagnosis and treatment in a practical way for clinical use, and how to incorporate new treatments into patient care to improve survival in this subset of patients. Finally, these recommendations are integrated into a sample order set developed by members of the Chronic Liver Disease Foundation and experts in the management of HRS-AKI.

Responsiveness to Vasoconstrictor Therapy in Hepatorenal Syndrome Type 1

Key Points

Raising the mean arterial pressure (MAP) during management of hepatorenal syndrome type 1 (HRS-1) is associated with improvement in kidney function, independently of baseline MAP or model for end-stage liver disease. Raising the MAP by 15 mm Hg or greater leads to greater reduction in serum creatinine in HRS-1. Norepinephrine use confers greater probability of improvement in kidney function in HRS-1 compared with midodrine/octreotide.

Background

Raising mean arterial pressure (MAP) during treatment of hepatorenal syndrome type 1 (HRS-1) with vasoconstrictors (VCs) is associated with renal recovery. However, the optimal MAP target and factors associated with response to VCs remain unclear.

Methods

Records from hospitalized patients with HRS-1 treated with VCs without shock were reviewed searching for those who achieved ≥5 mm Hg rise in MAP within 48 hours. We examined the relationship between the mean MAP achieved during the first 48–72 hours of VC therapy and the change in serum creatinine (sCr) up to day 14. Endpoints were >30% reduction in sCr without need for dialysis or death by day 14 (primary) or by day 30 (secondary).

Results

Seventy-seven patients with HRS-1 treated for 2–10 days with either norepinephrine (n =49) or midodrine/octreotide (n =28) were included. The median age was 52 years (interquartile range [IQR], 46–60), 40% were female, and 48% had alcoholic cirrhosis. At VC initiation, median MAP was 70 mm Hg (IQR, 66–73), and median sCr was 3.8 mg/dl (IQR, 2.6–4.9). When analyzed by tertiles of mean MAP increment (5–9, 10–14, ≥15 mm Hg), there was greater reduction in sCr with greater rise in MAP (ANOVA for trend, P < 0.0001). By multivariate logistic regression analysis, mean MAP rise during the first 48–72 hours (odds ratio [OR], 1.15 [1.02 to 1.299], P =0.025), norepinephrine as VC (OR, 5.46 [1.36 to 21.86], P =0.017), and baseline sCr [OR, 0.63 [0.41 to 0.97], P =0.034) were associated with the primary endpoint, whereas mean MAP rise during the first 48–72 hours (OR, 1.17 [1.04 to 1.33], P =0.012) and baseline sCr (OR, 0.63 [0.39 to 0.98], P =0.043) were associated with the secondary endpoint.

Conclusions

Greater magnitude of rise in MAP with VC therapy in HRS-1, lower baseline sCr, and use of norepinephrine over midodrine/octreotide are associated with kidney recovery. Targeting an increment of MAP ≥15 mm Hg may lead to favorable renal outcomes.

Spontaneous peritoneal drainage following paracentesis in a hospitalized patient with resolution of type 1 hepatorenal syndrome

The hepatorenal syndrome develops in a small percentage of patients with advanced liver disease. The pathogenesis involves intravascular volume contraction secondary to pooling of blood in the splanchnic vessels, stimulation of the sympathetic nervous system and the renin-angiotensin-aldosterone pathway, and increased intra-abdominal pressure secondary to the formation of large volumes of ascitic fluid. The treatment options are limited, and liver transplant is the only definitive form of management. Here we suggest an alternative approach to treating hepatorenal syndrome based on the unexpected continuous peritoneal drainage in a 36-year-old man hospitalized with hepatic encephalopathy and hepatorenal syndrome. A total of 11.2 L ascitic fluid drained over 5 days from a paracentesis puncture site with marked improvement in renal function; the creatinine decreased from 3.3 mg/dL to 0.7 mg/dL and the BUN decreased from 42 mg/dL to 10 mg/dL. The discussion with this case report summarizes the pathogenesis, including the effect of intra-abdominal pressure, of the hepatorenal syndrome, outlines medical management, and makes a proposal for clinical study based on this case.

Acute Kidney Injury in Patients with Liver Disease

AKI is commonly encountered in patients with decompensated cirrhosis, and it is associated with unfavorable outcomes. Among factors specific to cirrhosis, hepatorenal syndrome type 1, also referred to as hepatorenal syndrome-AKI, is the most salient and unique etiology. Patients with cirrhosis are vulnerable to traditional causes of AKI, such as prerenal azotemia, acute tubular injury, and acute interstitial nephritis. In addition, other less common etiologies of AKI specifically related to chronic liver disease should be considered, including abdominal compartment syndrome, cardiorenal processes linked to cirrhotic cardiomyopathy and portopulmonary hypertension, and cholemic nephropathy. Furthermore, certain types of GN can cause AKI in cirrhosis, such as IgA nephropathy or viral hepatitis related. Therefore, a comprehensive diagnostic approach is needed to evaluate patients with cirrhosis presenting with AKI. Management should be tailored to the specific underlying etiology. Albumin-based volume resuscitation is recommended in prerenal AKI. Acute tubular injury and acute interstitial nephritis are managed with supportive care, withdrawal of the offending agent, and, potentially, corticosteroids in acute interstitial nephritis. Short of liver transplantation, vasoconstrictor therapy is the primary treatment for hepatorenal syndrome type 1. Timing of initiation of vasoconstrictors, the rise in mean arterial pressure, and the degree of cholestasis are among the factors that determine vasoconstrictor responsiveness. Large-volume paracentesis and diuretics are indicated to relieve intra-abdominal hypertension and renal vein congestion. Direct-acting antivirals with or without immunosuppression are used to treat hepatitis B/C-associated GN. In summary, AKI in cirrhosis requires careful consideration of multiple potentially pathogenic factors and the implementation of targeted therapeutic interventions.

Application of New Acute Kidney Injury Biomarkers

Kidney-related biomarkers can provide structural and functional information about different parts of the nephron. These biomarkers can be used to evaluate glomerular, tubular, or interstitial injury, inflammation, or repair, and glomerular or tubular function. Furthermore, biomarkers can improve the acute kidney injury diagnosis in various clinical conditions, including acute interstitial nephritis, acute tubular injury, hepatorenal and cardiorenal syndrome, ischemic and nephrotoxic acute kidney injury, and drug-induced acute kidney injury. Biomarkers might be used as an additional precision medicine tool in managing patients with acute kidney injury; they can help with clinical decision-making and impact patient outcomes. In this chapter, we reviewed the utility of biomarkers used in acute kidney injury.

Update on hepatorenal Syndrome: Definition, Pathogenesis, and management

Hepatorenal syndrome (HRS) is acute kidney injury (AKI) that occurs without evidence of structural abnormalities in the kidneys in patients with liver disease. It is thought to be due to splanchnic vasculature dilatation that is associated with intense increase of renal arteries' tone, leading to renal cortex ischemia and AKI. Nitric oxide, endotoxins, neurohormonal changes, bacterial infection, high serum bilirubin and bile acids are examples for factors contributing to HRS development. Nevertheless, other unknown factors may have role in HRS pathophysiology. Hence, further discussion and research are needed to clearly understand HRS. Plasma volume restoration and vasoconstrictors are the cornerstone of HRS treatment. Others such as octreotide, noradrenaline, infection control, systemic inflammatory response prevention, shunting, and renal replacement therapy are currently used to manage HRS. Liver or combined liver and kidney transplantation is currently the ultimate cure for HRS. This review was written to help in better understanding the pathogenesis, diagnosis, and treatment options for HRS.

Hepatorenal Syndrome Type 1: From Diagnosis Ascertainment to Goal-Oriented Pharmacologic Therapy

Hepatorenal syndrome type 1 (HRS-1) is a serious form of AKI that affects individuals with advanced cirrhosis with ascites. Prompt and accurate diagnosis is essential for effective implementation of therapeutic measures that can favorably alter its clinical course. Despite decades of investigation, HRS-1 continues to be primarily a diagnosis of exclusion. Although the diagnostic criteria dictated by the International Club of Ascites provide a useful framework to approach the diagnosis of HRS-1, they do not fully reflect the complexity of clinical scenarios that is often encountered in patients with cirrhosis and AKI. Thus, diagnostic uncertainty is often faced. In particular, the distinction between HRS-1 and acute tubular injury is challenging with the currently available clinical tools. Because treatment of HRS-1 differs from that of acute tubular injury, distinguishing these two causes of AKI has direct implications in management. Therefore, the use of the International Club of Ascites criteria should be enhanced with a more individualized approach and attention to the other phenotypic aspects of HRS-1 and other types of AKI. Liver transplantation is the most effective treatment for HRS-1, but it is only available to a small fraction of the affected patients worldwide. Thus, pharmacologic therapy is necessary. Vasoconstrictors aimed to increase mean arterial pressure constitute the most effective approach. Administration of intravenous albumin is an established co-adjuvant therapy. However, the risk for fluid overload in patients with cirrhosis with AKI is not negligible, and interventions intended to expand or remove volume should be tailored to the specific needs of the patient. Norepinephrine and terlipressin are the most effective vasoconstrictors, and their use should be determined by availability, ease of administration, and attention to optimal risk-benefit balance for each clinical scenario.

Hepatorenal syndrome in acute-on-chronic liver failure with acute kidney injury: more questions requiring discussion

In cirrhosis with ascites, hepatorenal syndrome (HRS) is a specific prerenal dysfunction unresponsive to fluid volume expansion. Acute-on-chronic liver failure (ACLF) comprises a group of clinical syndromes with multiple organ failure and early high mortality. There are differences in the characterization of ACLF between the Eastern and Western medical communities. Patients with ACLF and acute kidney injury (AKI) have more structural injuries, contributing to confusion in diagnosing HRS-AKI. In this review, we discuss progress in the pathogenesis, diagnosis, and management of HRS-AKI, especially in patients with ACLF. Controversy regarding HRS-AKI in ACLF and acute liver failure, hepatic carcinoma, shock, sepsis, and chronic kidney disease is also discussed. Research on the treatment of HRS-AKI with ACLF needs to be more actively pursued to improve disease prognosis.

Hepatorenal syndrome: a Nationwide Trend Analysis from 2008 to 2018

OBJECTIVE

This study was designed to assess the epidemiological trends and outcomes associated with Hepatorenal Syndrome (HRS).

METHODS

This retrospective interrupted trend study used the Nationwide Inpatient Sample (NIS) database for the years 2008, 2012, 2014, 20z16 and 2018 to identify adult (≥18 years) hospitalizations with a primary diagnosis of HRS. We determined epidemiological characteristics and trends for HRS hospitalizations. Additionally, we also calculated the inpatient mortality, mean length of stay (LOS) and mean total hospital charge (THC) using a multivariate regression trend analysis.

RESULTS

There was an increase in the total number of HRS hospitalizations from 22,864 in 2008 to 42,985 in 2018 with a trend towards increasing hospitalizations (p-trend <.001). The mean age for these hospitalizations ranged from 57.4-59.0 years with a significantly rising trend (p-trend <.001). Although the majority of HRS hospitalizations were men, we observed a trend towards increasing hospitalizations for women with an increase from 35.7% in 2008 to 39% in 2018 (p-trend <.001). Additionally, Whites made up a majority of the sample size (Table 1). After a multivariate regression trend analysis, we found a statistically significant trend towards declining inpatient mortality from 36.2% in 2008 to 25.7% in 2018 (p-trend <.001) for HRS hospitalizations (Table 2). We did not find a statistically significant trend for LOS and THC.[Table: see text][Table: see text].

CONCLUSION

Total hospitalizations, hospitalizations for women and the mean age for HRS hospitalizations were on the rise between 2008 and 2018. However, the inpatient mortality declined.KEY MESSAGESIn the United States, there was a trend towards increasing hospitalizations and mean age for HRS.Although a male predominance was noted, HRS hospitalizations for women were on the rise.The inpatient mortality for HRS hospitalizations was on a decline and may indicate significant improvements in management.

Hillien SA, Kalim S, Nigwekar SU, Flood JG, Nixon A, Simonetto DA, Juncos LA, Karakala N, Wadei HM, Regner KR, Belcher JM, Nadim MK, Garcia-Tsao G, Velez JCQ, Parikh SM, Chung RT. Urinary NGAL as a Diagnostic and Prognostic Marker for Acute Kidney Injury in Cirrhosis: A Prospective Study

INTRODUCTION

Urinary neutrophil gelatinase-associated lipocalin (NGAL) has shown promise in differentiating acute tubular necrosis (ATN) from other types of acute kidney injuries (AKIs) in cirrhosis, particularly hepatorenal syndrome (HRS). However, NGAL is not currently available in clinical practice in North America.

METHODS

Urinary NGAL was measured in a prospective cohort of 213 US hospitalized patients with decompensated cirrhosis (161 with AKI and 52 reference patients without AKI). NGAL was assessed for its ability to discriminate ATN from non-ATN AKI and to predict 90-day outcomes.

RESULTS

Among patients with AKI, 57 (35%) had prerenal AKI, 55 (34%) had HRS, and 49 (30%) had ATN, with a median serum creatinine of 2.0 (interquartile range 1.5, 3.0) mg/dL at enrollment. At an optimal cutpoint of 244 μg/g creatinine, NGAL distinguished ATN (344 [132, 1,429] μg/g creatinine) from prerenal AKI (45 [0, 154] μg/g) or HRS (110 [50, 393] μg/g; P < 0.001), with a C statistic of 0.762 (95% confidence interval 0.682, 0.842). By 90 days, 71 of 213 patients (33%) died. Higher median NGAL was associated with death (159 [50, 865] vs 58 [0, 191] μg/g; P < 0.001). In adjusted and unadjusted analysis, NGAL significantly predicted 90-day transplant-free survival (P < 0.05 for all Cox models) and outperformed Model for End-Stage Liver Disease score by C statistic (0.697 vs 0.686; P = 0.04), net reclassification index (37%; P = 0.008), and integrated discrimination increment (2.7%; P = 0.02).

DISCUSSION

NGAL differentiates the type of AKI in cirrhosis and may improve prediction of mortality; therefore, it holds potential to affect management of AKI in cirrhosis.

Monitoring Renal Function and Therapy of Hepatorenal Syndrome Patients with Cirrhosis

Acute kidney injury (AKI) is a frequent complication in patients with cirrhosis. Patients with cirrhosis can develop AKI due to different causes. Hepatorenal syndrome (HRS) is a unique cause of AKI occurring in patients with advanced cirrhosis and is associated with high short-term mortality. The differential diagnosis between different causes of AKI may be challenging. In this regard, new urine biomarkers may be helpful. Liver transplantation is the definitive treatment of patients with HRS-AKI. Vasoconstrictors and albumin represent the first-line pharmacologic treatment of HRS-AKI. This review summarizes current knowledge for the diagnosis and management of HRS in cirrhosis.

Evidence-based protocol for diagnosis and treatment of hepatorenal syndrome is independently associated with lower mortality

BACKGROUND

Hepatorenal syndrome (HRS) is the deadliest complication of cirrhosis. The purpose of this study is to analyze if the use of a protocol for HRS is associated with higher survival in these patients.

METHODS

An evidence-based protocol for the diagnosis and treatment of HRS was instituted in 2013. Data from medical records from 2010 to 2016 were obtained by searching the hospital database for patients who received terlipressin, in the three years before and after the institution of the protocol. Data were reviewed to confirm the diagnosis of HRS and multiple variables were collected. Liver-specific scores were calculated and a stepwise Cox regression approach was used for univariate and multivariate analysis.

RESULTS

The study included 46 patients, 20 from the pre-protocol period and 26 from the post-protocol period. Respectively, mortality at 30 days, 90 days and 365 days was 75%, 75% and 90% for the pre-protocol period, and 61%, 69% and 80% for the post-protocol period. In the multivariate analysis, an aspartate aminotransferase (AST) of <40U/L, the pre-protocol period and higher Child-Turcotte-Pugh scores were associated with higher 30-day and 90-day mortality. The total mean dose of terlipressin and human albumin used per patient was reduced from 27mg to 22mg and from 236g to 144g, respectively, after the institution of the protocol. This was not associated with higher mortality.

CONCLUSION

The use of an evidence-based protocol for the treatment of HRS translated into a higher survival. The authors suggest that the use of evidence-based protocols for the diagnosis and treatment of HRS could reduce cost and mortality in tertiary hospitals.

Biomarkers of Acute and Chronic Kidney Disease

The current unidimensional paradigm of kidney disease detection is incompatible with the complexity and heterogeneity of renal pathology. The diagnosis of kidney disease has largely focused on glomerular filtration, while assessment of kidney tubular health has notably been absent. Following insult, the kidney tubular cells undergo a cascade of cellular responses that result in the production and accumulation of low-molecular-weight proteins in the urine and systemic circulation. Modern advancements in molecular analysis and proteomics have allowed the identification and quantification of these proteins as biomarkers for assessing and characterizing kidney diseases. In this review, we highlight promising biomarkers of kidney tubular health that have strong underpinnings in the pathophysiology of kidney disease. These biomarkers have been applied to various specific clinical settings from the spectrum of acute to chronic kidney diseases, demonstrating the potential to improve patient care.

Reappraising the spectrum of AKI and hepatorenal syndrome in patients with cirrhosis

The occurrence of acute kidney injury (AKI) in patients with end-stage liver disease constitutes one of the most challenging clinical scenarios in in-hospital and critical care medicine. Hepatorenal syndrome type 1 (HRS-1), which is a specific type of AKI that occurs in the context of advanced cirrhosis and portal hypertension, is associated with particularly high mortality. The pathogenesis of HRS-1 is largely viewed as a functional derangement that ultimately affects renal vasculature tone. However, new insights suggest that non-haemodynamic tubulo-toxic factors, such as endotoxins and bile acids, might mediate parenchymal renal injury in patients with cirrhosis, suggesting that concurrent mechanisms, including those traditionally associated with HRS-1 and non-traditional factors, might contribute to the development of AKI in patients with cirrhosis. Moreover, histological evidence of morphological abnormalities in the kidneys of patients with cirrhosis and renal dysfunction has prompted the functional nature of HRS-1 to be re-examined. From a clinical perspective, a diagnosis of HRS-1 guides utilization of vasoconstrictive therapy and decisions regarding renal replacement therapy. Patients with cirrhosis are at risk of AKI owing to a wide range of factors. However, the tools currently available to ascertain the diagnosis of HRS-1 and guide therapy are suboptimal. Short of liver transplantation, goal-directed haemodynamically targeted pharmacotherapy remains the cornerstone of treatment for this condition; improved understanding of the underlying pathogenic mechanisms might lead to better clinical outcomes. Here, we examine our current understanding of the pathophysiology of HRS-1 and existing challenges in its diagnosis and treatment.

Low Mean Arterial Blood Pressure is Independently Associated with Postoperative Acute Kidney Injury After Living Donor Liver Transplantation: A Propensity Score Weighing Analysis

Background

As end-stage liver disease progresses, renal blood flow linearly correlates with mean arterial blood pressure (MBP) due to impaired autoregulation. We investigated whether the lower degree of postoperative MBP would predict the occurrence of postoperative acute kidney injury (AKI) after liver transplantation.

Material/Methods

This retrospective study enrolled 1,136 recipients with normal preoperative kidney function. Patients were categorized into two groups according to the averaged postoperative MBP: <90 mmHg (MBP_below90) and ≥90 mmHg (MBP_over90). The primary endpoint was occurrence of postoperative AKI, defined by the creatinine criteria of the Kidney Disease Improving Global Outcomes. The logistic regression model with inverse probability treatment weighting (IPTW) of propensity score was used to compare the risk of postoperative AKI between two groups.

Results

MBP_below90 group (83.0±5.1 mmHg) showed higher prevalence and risk of postoperative AKI (74.2% versus 62.6%, p<0.001; IPTW-OR 1.34 [1.12–1.61], p=0.001) compared with MBP_over90 group (97.3±5.2 mmHg). When stratified by quartiles of baseline cystatin C glomerular filtration ratio (GFR), the association between MBP_below90 and postoperative AKI remained significant only with the lowest quartile (cystatin C GFR ≤85 mL/min/1.73 m²; IPTW-OR 2.24 [1.53–3.28], p<0.001), but not with 2^nd–4^th quartiles.

Conclusions

Our results suggest that maintaining supranormal MBP over 90 mmHg may be beneficial to reduce the risk of post-LT AKI, especially for liver transplant recipients with cystatin C GFR ≤85 mL/min/1.73 m².

BP Reduction, Kidney Function Decline, and Cardiovascular Events in Patients without CKD

BACKGROUND AND OBJECTIVES

In the Systolic Blood Pressure Intervention Trial (SPRINT), intensive systolic BP treatment (target <120 mm Hg) was associated with fewer cardiovascular events and higher incidence of kidney function decline compared with standard treatment (target <140 mm Hg). We evaluated the association between mean arterial pressure reduction, kidney function decline, and cardiovascular events in patients without CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We categorized patients in the intensive treatment group of the SPRINT according to mean arterial pressure reduction throughout follow-up: <20, 20 to <40, and ≥40 mm Hg. We defined the primary outcome as kidney function decline (≥30% reduction in eGFR to <60 ml/min per 1.73 m2 on two consecutive determinations at 3-month intervals), and we defined the secondary outcome as cardiovascular events. In a propensity score analysis, patients in each mean arterial pressure reduction category from the intensive treatment group were matched with patients from the standard treatment group to calculate the number needed to treat regarding cardiovascular events and the number needed to harm regarding kidney function decline.

RESULTS

In the intensive treatment group, 1138 (34%) patients attained mean arterial pressure reduction <20 mm Hg, 1857 (56%) attained 20 to <40 mm Hg, and 309 (9%) attained ≥40 mm Hg. Adjusted hazard ratios for kidney function decline were 2.10 (95% confidence interval, 1.22 to 3.59) for mean arterial pressure reduction between 20 and 40 mm Hg and 6.22 (95% confidence interval, 2.75 to 14.08) for mean arterial pressure reduction ≥40 mm Hg. In propensity score analysis, mean arterial pressure reduction <20 mm Hg presented a number needed to treat of 44 and a number needed to harm of 65, reduction between 20 and <40 mm Hg presented a number needed to treat of 42 and a number needed to harm of 35, and reduction ≥40 mm Hg presented a number needed to treat of 95 and a number needed to harm of 16.

CONCLUSIONS

In the intensive treatment group of SPRINT, larger declines in mean arterial pressure were associated with higher incidence of kidney function decline. Intensive treatment seemed to be less favorable when a larger reduction in mean arterial pressure was needed to attain the BP target.

Perspective on Clinical Application of Biomarkers in AKI

Several biomarkers of renal injury have been identified but the utility of these biomarkers is largely confined to research studies, whereas widespread clinical applicability is limited. This is partly because the use of serum creatinine as the comparator has several limitations and restricts the full interpretation of biomarker performance. To highlight the potential for clinical application of biomarkers, the most pertinent biomarker data are summarized here, using clinically relevant scenarios in which biomarkers could assist with diagnostic and management dilemmas. The paradigms proposed in this review aim to enhance the clinical diagnosis, management, and prognosis of AKI through the combined use of available clinical markers and novel inflammatory, injury, and repair biomarkers.

[Hepatorenal syndrome in decompensated cirrhosis : A special form of acute renal failure]

Renal failure is a serious complication in patients with advanced cirrhosis. It occurs in about 20 % of patients hospitalized with cirrhosis. In about 70 % it is caused by prerenal failure, and in 30 % it is due to intrarenal causes. In about 70 % of patients with rperenal failure, renal function can be restored with fluid replacement, but the remaining 30 % are unresponsive to volume expansion. Minor increase in serum creatinine have been shown to be clinically relevant and can adversely affect survival. Therefore early efforts should be made to avoid precipitation of renal failure.Hepatorenal syndrome (HRS) is a  fully reversible impairment of renal function in patients with cirrhosis unresponsive to volume expansion characterized by an acute progressive decrease in kidney function (serumcreatinin > 1,5 mg/dl) - type 1 HRS, whereas type 2 HRS features a decrease in kidney function over a long time, mostly in patients with refractory ascites. Therapy with vasoconstrictors like terlipressin to reverse splanchnic vasodilation, together with albumin is effective in 30-50 % of patients with HRS 1 and improves survival. The only effective longterm therapy is livertransplantation. An improvement of kidney fuction before transplantation is associated with a better outcome and posttransplant kidney function.