Porto-Sinusoidal Vascular Disorder: A Comprehensive Review

Porto-sinusoidal vascular disorder (PSVD) is an umbrella term proposed by the Vascular Liver Disease Interest Group (VALDIG) in 2019. It refers to a group of non-cirrhotic vascular liver diseases that cause portal hypertension. These were previously described as idiopathic non-cirrhotic portal hypertension, hepatoportal sclerosis, nodular regenerative hyperplasia, and incomplete septal fibrosis. PSVD is characterized by injury and remodeling of portal venules and sinusoids. Immune dysregulation, prothrombotic states, infections, medications (e.g., oxaliplatin, thiopurines), toxins (e.g., arsenic), and genetic susceptibility often drive this process. Clinically, PSVD ranges from asymptomatic patients with only abnormal liver tests to severe complications of portal hypertension, such as variceal bleeding, ascites, and portal vein thrombosis. Patients typically have preserved liver synthetic function, helping distinguish PSVD from cirrhosis. Diagnosis is based on VALDIG criteria and requires an adequate liver biopsy that shows no cirrhosis. It also requires specific combinations of clinical signs of portal hypertension and characteristic histological lesions, such as obliterative portal venopathy, nodular regenerative hyperplasia, and incomplete septal fibrosis. Non-invasive tools, including imaging and liver stiffness measurement, are supportive. They often show discordance between marked portal hypertension and low liver stiffness, suggesting a non-cirrhotic cause. Management follows cirrhosis-based portal hypertension guidelines. This includes non-selective beta-blockers, endoscopic variceal ligation, TIPS, anticoagulation in selected patients, and liver transplantation for refractory or end-stage disease. Prognosis is generally better than in cirrhosis, with a 5-year transplant-free survival rate of approximately 85% compared to 60% in matched cirrhotics. However, major gaps remain in the true epidemiology, the natural history of early or subclinical PSVD, validated non-invasive biomarkers, and disease-modifying therapies.