Dear zephyr,
Yes, there are non-ionic contrasts available. However, your wife should still be pre-medicated. Any cardiologist at a high volume center will have experience with dealing with contrast reactions. This is something we routinely see at the Cleveland Clinic and it can usually be managed without difficulty. If you would like to be seen at the Cleveland Clinic I would recommend Dr. Fred Heupler. He is an expert in the area of contrast reactions. You can make an appointment with him by calling the number below. Best wishes.