Hepatorenal syndrome (HRS) is a common cause of acute kidney injury (AKI) in patients with liver disease [1]. Increased activity and presence of vasodilators such as nitric oxide in cirrhotic patients leads to vasodilation, especially in the splanchnic circulation, resulting in hemodynamic changes that precipitate renal injury [1]. Patients may present with elevated serum creatinine (Cr), benign urine sediment, and low urine sodium [1].

There are two main classifications of HRS: HRS-AKI (previously known as type 1 HRS) and diuretic-resistant ascites (previously known as type 2 HRS) [1].

The ultimate treatment for patients with HRS is to improve hepatic function via treatment of underlying etiology or liver transplantation; however, this is not always immediately possible due to the high demand for liver transplantation among other factors [1]. Continuous renal replacement therapy (CRRT) can also be considered, especially in patients with severe electrolyte derangements such as hypokalemia or pulmonary edema, that are not responding to medical therapy [1]. Often, CRRT is used as a bridging therapy to stabilize patients until they are optimized for receiving a liver transplant [1, 2]. CRRT, however, comes with its own risks and disadvantages such as hypotension and increased risk of cardiac adverse events [2]. In certain cases, transjugular intrahepatic portosystemic shunts (TIPS) can benefit patients with HRS by reducing portal pressure resulting in increase in renal perfusion [1].

Inclusion Criteria:

• All patients >18 years old that were hospitalized between April 1st 2019 and April 1st 2023 who either presented with HRS-AKI or developed a diagnosis of HRS during the hospital course. HRS-AKI will be defined based on the ICA criteria, described below:

  1. Presence of cirrhosis, acute liver failure, or acute-on-chronic liver failure
  2. An increase in serum Cr of ≥0.3 mg/dL within 48 hours or ≥50% from baseline value and/or urinary output ≤0.5 mL/kg of body weight for ≥6 hours (requires use of a urinary catheter)
  3. No full or partial response for ≥2 days of diuretic withdrawal and volume expansion with albumin (dosed at 1 g/kg of body weight/day)
  4. Absence of shock
  5. No current or recent treatment with nephrotoxic drugs
  6. Absence of parenchymal renal disease
  7. Suggestion of renal vasoconstriction based on FENa <0.2%

Exclusion Criteria:

• 1. HRS-AKI patients <18 years of age 2. All patients hospitalized between April 1st 2019 and April 1st 2023 without a diagnosis of HRS-AKI.

- All patients >18 years old that were hospitalized between April 1st 2019 and April 1st 2023 who either presented with HRS-AKI or developed a diagnosis of HRS during the hospital course. HRS-AKI will be defined based on the ICA criteria, described below:

1. Presence of cirrhosis, acute liver failure, or acute-on-chronic liver failure
2. An increase in serum Cr of ≥0.3 mg/dL within 48 hours or ≥50% from baseline value and/or urinary output ≤0.5 mL/kg of body weight for ≥6 hours (requires use of a urinary catheter)