Hi Tom,
I had AVR and take Coumadin. I also travel often. I have not had any troubles when I travel. Prior to obtaining my own home testing unit for my INR, I would have my INR checked just prior to my trip. I would try to stay on a my regular routine when traveling, and then upon return, have my level checked again. Once while away for an extended period, I felt that my levels might be too high, so I went to the local ER, and told them I was a heart patient, they took me right in, contacted my doctor, so that he could fax them the orders to test, and then they ran my INR check. They called the results into my doctor, and he contacted me within 4 hours.
You may want to ask your doctor for an order to check your INR that you can take with you. You may also ask him to include on there, that they provide both you and your doctor with the results. This may save time.
I flew from Nashville to Maui just 10 weeks after surgery, and stayed there for 2 weeks. No problems.
Now that I have my own home testing unit. I take ith with me if I am going to be out of town for more than a week at a time.
Hope this helps,
Rob