You need to see a cardiologist to evaluate and treat your problems. Any time there is plaque building in the arteries, it is a need for concern. Also, if plaque is building in one area, it's usually building in another. You have a lot of heart issues to be so young, and need to be under the care of a cardiologist.
You should monitor the atherosclerosis of your Aorta. The plaque and thickening can get quite severe, so you want to make sure that it does not get to the severe stage. What can happen, is the plaque can harden into a porcelein valve. A porcelein valve is a problem with surgery in that sometimes the heart surgeon cannot do anything with it. Find out what stage the aorta is in from your cardiologist. With your past symptoms, it would be wise to be seeing a cardiologist. The plaque in the cartoid artery should also be monitored. Request a test to be done to see how much inflammation you have in your body. People who have a lot of inflammation are more likely to get the plaque buildup in their arteries, valves, and heart muscle. The inflammation causes a sticky spot where the plaque sticks. Ask your doctor what you can do to bring down inflammation in your body. Being that you have Crohns, I am sure that you are already eating healthy. Take care.