Diagnostic Approach: Portosystemic Vascular Anomalies (psva)

Key Points: • PSVA/MVD syndrome is a complex polygenic trait causing hepatic portal hypoperfusion. PSVA and MVD usually cannot be distinguished by liver biopsy alone. • PSVA associates with historical & clinicopathologic features lacking in MVD: low RBC MCV, cholesterol, BUN, creatinine, urine SG, and ammonium biurate crystalluria and uroliths • PSVA associates with low Protein C activity (100% I-PSVA, 79% E-PSVA) unlike MVD • Liver biopsy done to document the PSVA/MVD syndrome, requires samples from 3 liver lobes avoiding the caudate lobe (receives first branch of the portal vein even in many PSVA) • Excellent definitive imaging can be done using contrast enhanced multisector CT with 3 dimensional reconstruction for definitive identification of PSVA and surgical planning. • For a yes/no shunting query: microbubble ultrasound study (splenic injection) or colorectal or per-splenic technetium pertechnetate study are less subjective than colorflow ultrasonography.