Clearly your doctor and the surgeon should be able to advise, perhaps you could ask them specifically to consult with your Cardiologist.
For my limited knowledge, but still an person who has undergone heart surgery, I don't think there is any problem - unless of course, you have to let the sinus surgery heal before subjecting your both to intrusions in your breathing passage. I think, have been there, a breathing tube goes directly to the lungs, and so your nose has nothing to do with it.
I ask that you consider making a post on the Ears, Nose and Throat Community document your experience and asking for input.
http://www.medhelp.org/forums/Ear--Nose--Throat/show/70