Unfortunately, there is no good data for any of this. One option, however, is to be bridged with heparin until the day of the surgery (heparin has a very short half life and can be discontinued few hours prior to the operation) and then restarted a day after his operation assuming that there are no complications. Some also advocate doing a TEE to see if there is clot in the left atrium and if so postpone the operation until it resolves. This is something one might recommend in someone with high risk for clot such as heart failure, DM, previous embolic stroke, etc. It is generally quite safe to come off coumadin prior to these types of surgeries and this is typically what is done here at the cleveland clinic. Again, high risk patients could consider bridging with heparin.
I recently had an outpatient procedure and also had to stop coumadin for 5 days before. What I did was stop the Coumadin 5 days before, and then 4 days before started Lovenox to bridge up until the surgery (Lovenox is a subcutaneous injection and is a Low Molecular Weight Heparin that will keep the blot thin enough to prevent clotting). The night of the day of the procedure I had, I restarted the Coumadin, and the following day after the surgery used Lovenox for 2 days giving the Coumadin time to begin building back up again. Speak with your husband's cardiologist who can oversee this for you.