I don't agree with the reading. If your CAC is 400+ It is not necessary to have the stress and EKG tests but the risk of a stroke or heart attack exists. It will exist forever although you can stabilize your condintin by improving life style (diet, exercise + statins). I am asymptomatic but my score is close to 1600. Numbers don't lie. My liver produces too much cholesterol.
As far as the angiogram the imaging of the blockage in your arteries are facts as well. I didn't run to the angiogram believe me but with a score like the one I have I needed to know the exact blockage percentage on my LAD.