Welcome, embolization. I hate hearing about people who need medical treatment and it's out of reach due to money.
The way pelvic venous congestion ties in to CCSVI is because of the occasional case of renal vein compression in CCSVI. The renal vein carries a very high amount of flow (500ml/min?). When it's blocked, all that flow needs to find other routes. The flow can be diverted up along the lumbar veins and the azygous vein. Abnormal flow in the azygous vein is implicated in CCSVI. The blocked renal vein flow can also be diverted to the pelvic veins. This extra flow can knock out a pelvic vein valve, leading to congestion and dysfunction of the pelvic veins. Not all cases of pelvic vein congestion have renal vein blockages involved but it's the situation we've heard about that's relevant to CCSVI. It's not something I've personally experienced, but we've had at least one TiMS member who needed treatment for pelvic vein congestion.