IVC
Infrarenal:
- Duplicated IVC - typically drains to left renal vein (persistent bilateral supracardinal veins)
- Left-sided IVC (persistent left supracardinal vein)
- Mega cava (~ > 30 mm )
- Persistent right posterior cardinal vein (retrocaval or circumcaval ureter)
- Absent infrarenal IVC
Suprarenal:
- IVC agenesis/hypoplasia
- Azygos continuaiton
Renal:
- Circumaortic left renal vein
- Retroaortic left renal vein
Filter considerations
- Duplicated IVC - can place two filters or a single suprarenal filter
- Agenesis - don’t place
- Azygos continuation - infrarenal should still work
- Mega - can place bilateral iliac vein filters or a larger Bird’s Nest filter
- Circumaortic renal - place inferior to the inferior moeity
SVC
- SVC duplication - normal right SVC remains and embryonic left anterior cardinal vein fails to regress
- Possible drainage to RA, coronary sinus, or left atrium
- More common that isolated left sided SVC
- Left sided SVC - persistent left anterior cardinal vein
- Most common congenital venous anomaly in the chest
- Drainage most often to coronary sinus (92% of time) but rarely can be to LA resulting in R-to-L shunting