Will treatment with bcg for bladder cancer cause possible complications to a recent aortic tissue valve replacement?

It should not: Bcg is a vaccine that used to treat superficial bladder cancer. I don't think it would give you any significant complication with your recent aortic tissue valve replacement.

Not likely: This is a reasonable concern, but this would be an unusual complication. A 2010 study in journal of urology found that this complication is no more likely in patients with valves and other prostheses than in the general population, and that having a valve should not prevent you from receiving this treatment.