3.7 INR level and am taking Warfarin Is that too high?

My advice would be to ask your doctor about that. I have had 2 lots of open heart surgery. The first to replace a defective aortic valve with an artificial valve, and the surgeon wanted me to maintain my INR between 2.0 and 3.0 telling me that 2.7 was ideal. The second surgery was to replace my ascending aorta due to an aneurysm and replace it with a graft. The surgeon wants me to maintain an INR of between 2.5 and 3.5 now. Therefore one would suppose that depending on what you have had done and the manufacturers and surgeons recommendations for the prosthesis that you have, your INR that the surgeon wants may be lower, higher, or even where it is, so check with your doctor.

Cheers

Dennis