Before questioning accuracy of stress Echocardiography it is better to understand what it does, it helps in visually seeing the function of heart/muscles/chambers as whole during stress induced by medication (like dobutamine) or physical activity. If at all it is normal or any abnormality in motion of heart wall/valves and function can be identified by the test and it doesn't help in finding Any blocks. For that you may need CORONARY ANGIOGRAPHY.
calcium deposit score of zero and having CAD is possible and need much detailed explanation for it.
Health Tips
may consult cardiologist if needed.