Lithotripsy Procedure

My husband had mitral valve repair and then a stoke 10 months later followed by a smaller stroke 6 months after that.  He is on warfarin and has been told he should have the procedure lithotripsy done because of a large stone near his kidney.  He hasn't any symptoms when drinking water regularly.  I'm very concerned that he could have risks due to taking blood thinner and having so many other health issues.  Also, going off the warfarin and perhaps bridging with heaparin doesn't sound good either.

Your advice is greatly appreciated.

Barbara