A 52-year-old man with a 10-year history of cirrhosis due to hepatitis C presents to the emergency department with hematemesis and melena. On examination, he is tachycardic (HR 110/min), hypotensive (BP 85/50 mmHg), and has clinical signs of portal hypertension (splenomegaly, ascites, spider angiomas). Laboratory investigations show: Hemoglobin 7.8 g/dL, platelets 45,000/μL, INR 2.8, aPTT 48 s, albumin 2.1 g/dL, total bilirubin 4.2 mg/dL. Upper endoscopy confirms bleeding esophageal varices. Which of the following best explains the coagulation abnormality in this patient?