A 52-year-old male with a 20-year history of heavy alcohol consumption presents with jaundice, ascites, and spider angiomas. Laboratory investigations show: total bilirubin 4.2 mg/dL, albumin 2.8 g/dL, INR 2.1, platelet count 85,000/μL, and AST 120 U/L (AST > ALT). Ultrasound shows cirrhotic liver with portal vein patency. What is the most appropriate next step in management?