I was diagnosed with coronary blockage 10 years ago at age 48. The diagnosis was done with an angiogram also called a heart catherterization. I went through all the usual test over a period of years prior to that, EKG, stress test, stress test with echo cardiogram, and contrast scan. The only one that showed any problem was the angiogram. The scan showed some indication of blockage but not like the angiogram. The angiogram showed four blockages 50%,75%, 70% and 100%. I had quadruple bypass in May 1999 as a result. I feel great today. I was and still am an ardent devotee of exercise. (three time a week with weights and five days a week running two to three miles, bicycle when the weather is good) No futher problems with my heart and no damage to the organ.
The angiogram is the most positive and most invasive of the tests. However, there may be some new methods with the CT scan. I am not up to date. My younger brother had a heart attack at 50 and as a result has two stints. This was 8 years ago and he is doing well.
I would suggest that you speak with the cardiologist about the accuracy of the test recommended. My test went on over a period of years before I had the incident that made me go in for the angiogram. I feel that had I had the angiogram seven years earlier I could have done the stints instead of surgery. Recovery time is a lot less and less stress on the body. Although, I have to admit, I was running two miles/day by the fifth week and lifting light weights by the tenth week after surgery.
Good luck with your prognosis. There is a lot that can be done today. The key is get good information from definitive tests so you know the extent of the problem. Then you can look at the alternatives for treatment based on facts. Who knows, all it may take is change of diet and some exercise.