A chemical (nuclear) stress test is a good start...it will determine if you need a cath or not. Or other option is a CTA of the cornory arteries. Not sure where you're at or what insurance you have, but many insurances are slow or no paying these. Around $700. A carotid doppler will also give a baseline idea if there is blockage. All these require a cardiologist. (Except some gp's are doing stress and echoes in office now).