Not all policies are created equal, and there may be some glaring omissions in what may seem like a good deal. Your credit card company may offer excess medical coverage when you are travelling. Find out what exactly the card may cover and, if it is not adequate, how to top it up. A representative from Texas may not know what a Quebecois should do. Reimbursement won't be of much help if you need expensive surgery and you don't have the cash or a credit card on hand.
Most policies exclude pre-existing conditions.
Make sure the insurance company knows of the condition and that it is covered.