Dave: If you can wean yourself off caffeine, do it. It does restrict the Capillaries in your blood system, and, obviously, would do the same with small blood vessels located anywhere, including your heart!
Back in the 70s, after I finished Law school, and was married to my first wife, she began calling me the " Rice Krispie Kid", because my ankle, knee, and occasionally even my hip joints would " Snap, Crackle, and POP", when I went to the bathroom in the early morning hours. The house was so quiet she could lay in bed and listen to me going and coming back.
In 1982, I began teaching Hunter Safety as a Volunteer Instructor, and to learn more about necessary first aid, I visited the libraries and read books to supplement what was in the booklet used for the course. At a local Surplus store, I found a small bookshelf with a booklet written by a California MD on Hypothermia. For $3.00, I bought it. He explained how bad caffeine is on the circulatory system, and how much stress it adds to keeping warm in cold weather. He was a California Skier, who drove up to the mountains to Ski on weekends from him home near LA.
I decided to try his advice, and stopped drinking everything that has caffeine in it. That includes, Coffee, Tea, cocoa, chocolate, Coke, Pepsi, Mountain Dew, and many other soft drinks.
I substituted soup, and heated soft drinks, or homemade "cool-ade" for the caffeine laden drinks in my canteen, and water bottles. I now drink more straight water, than either soups, or sweetened drinks, but the later two are a great help when its really cold out to get some heat working in your body.
About a month after I got off the caffeine, my wife woke up completely when I came back to bed after my nightly constitutional, and asked what "Happened" to my Snap, Crackle and Pop?" My joints had stopped making all that noise.
The noise was from fluids building up in my knees, because the veinous return system of my circulatory system could not carry the fluids out of the joints when the capillaries were closed.
I have stayed off coffee since, and cut back on, and then stopped all together smoking. If you have already had stint surgery on your heart vessels, you need to stop drinking caffeinated drinks Right Now. If you Smoke, Stop. I still have my pipe, and keep a pack of tobacco in a drawer, like an alcoholic keeps a bottle in his cupboard, and I still love the smell of my tobacco. But, I do not smoke it.
Best Wishes. Paul :hatsoff: