My doctor requesting me to do a ct angiogram because they see an abnormalities during my stress test, it is possible to make firts 2d echo exam before proceed to the ct angiogram? because ct angiogram is very expensive?

Specific tests are requested to define specific issues, here the quality of blood flow to regions of the heart. The echo does not provide that information, just the structure of the heart. The CT angiogram is less invasive and less costly than a heart cath that would gather similar information. It's your life, but I would get the angiogram if my stress test indicated its need.

The CT angiogram in your case is used to visualize the blood vessels around the heart and is less invasive than a cardiac catheterization. It sounds like your Dr is concerned about a blockage based off your abnormal stress test. An echo will show function/damage to the muscle but won’t show blockages in the vessels. I recommend discussing it with your cardiologist.