Can a blocled svc be repaired?

Yes. The svc (superior vena cava) can be surgically bypassed or sometimes reopened with angioplasty and a stent within the vein. Repair is only necessary for patients with significant facial swelling, difficulty breathing or swallowing. Usually, one's body can reroute blood around the blockage to a large degree.
Maybe. Interventional radiologists like myself can try to open with stents and balloons.