What are the symptoms of Hepatic Arteriovenous Malformations (AVMs)?

Hepatic Arteriovenous Malformation Symptoms

Most hepatic AVMs in HHT are asymptomatic, but when symptomatic, they present with three distinct clinical syndromes: high-output heart failure (most common), portal hypertension, or biliary ischemia. 1

Clinical Presentation Patterns

High-Output Heart Failure (Most Common)

• Shortness of breath and dyspnea on exertion are the predominant symptoms, resulting from arteriohepatic and/or portohepatic shunting creating a hyperdynamic circulatory state 1
• Ascites and peripheral edema develop as cardiac compensation fails 1
• This represents the leading complication, occurring at a rate of 1.2 per 100 person-years in patients with hepatic vascular malformations 1
• Atrial fibrillation occurs at 1.6 per 100 person-years, suggesting this arrhythmia is directly related to chronic cardiac overload rather than coincidental 1

Portal Hypertension

• Ascites is the most common manifestation, though variceal hemorrhage can occur 1
• Results from either arterioportal shunting with subsequent portal fibrosis or nodular regenerative hyperplasia from irregular hepatic blood flow 1
• Occurs at a comparable rate to heart failure (1.4 per 100 person-years) and accounts for approximately half of hepatic AVM-related deaths 1
• Notably, liver synthetic function and platelet count remain normal because these patients lack cirrhosis and do not develop hepatic insufficiency 1

Biliary Ischemia (Least Common but Most Lethal)

• Right upper quadrant abdominal pain with cholestasis (with or without cholangitis) characterizes this presentation 1
• Develops from shunting blood away from the peribiliary plexus, causing biliary strictures, dilation, and bile cysts 1
• Can progress to catastrophic "hepatic disintegration" with sudden severe right upper quadrant pain, bile duct necrosis, liver necrosis, cholangitis, sepsis, and/or liver hemorrhage 1
• Particularly lethal when occurring concurrently with high-output heart failure 1

Demographic and Temporal Features

• Symptoms typically appear around age 30 years and occur predominantly in females 1
• More common and symptomatic in families with ALK-1 mutations compared to endoglin mutations 1
• Only 8% of patients with hepatic vascular malformations are symptomatic in cross-sectional surveys, though longitudinal follow-up shows 25% will develop morbidity and 5% mortality over time 1

Less Common Presentations

• Hepatic encephalopathy from portovenous shunting, despite normal liver synthetic function 1
• Abdominal angina from mesenteric arterial "steal" through pancreaticoduodenal arteries 1
• Gastrointestinal bleeding more often results from gastrointestinal telangiectasias than variceal hemorrhage, even in patients with portal hypertension 1

Laboratory Abnormalities

• Elevated alkaline phosphatase and gamma-glutamyl-transpeptidase are the most common biochemical abnormalities, observed in approximately one-third of patients 1
• These elevations occur most prominently in the biliary presentation but can appear in other clinical types 1
• Anemia from chronic bleeding (hemoglobin <12.6 g/dL) is an independent predictor of symptomatic disease 2

Clinical Course Characteristics

• Presentations may occur concurrently or successively with spontaneous exacerbations and remissions 1
• The severity of vascular malformations correlates with clinical outcomes 1
• Common hepatic artery diameter >11 mm independently predicts heart failure symptoms (OR 2.554) 2

Critical Pitfall

Never perform liver biopsy in patients with proven or suspected hepatic AVMs due to catastrophic hemorrhage risk from the vascular malformations 1, 3