In the 2016 update of the stable<unk> <unk> <unk>  National Institute for Health and Clinical Excellence <unk>  has dramatically changed its approach to new-onset stable<unk> <unk>  aiming to find a more cost-effective strategy including NO use of pretest probability risk scores or NO use of functional tests such as stress echocardiography, as a first-line investigation. The suggestion is to use CT coronary angiography in patients with typical or atypical<unk> <unk> . In addition, there is no recommendation for any diagnostic testing if<unk> <unk>  is non-anginal. Also, perfusion imaging is recommended in the setting of uncertainty about the functional significance of coronary lesions. However, the recommendation of the European Society of Cardiology (ESC—2013) is performing functional tests as the initial investigation.
NICE guidelines for management of chest pain
Canadian cardiovascular society classification of angina pectoris
TIMI Risk Score for Unstable Angina or NSTEMI
Chronic stable angina echocardiography
Chronic stable angina positron emission tomography 
TIMI frame count 
Chronic stable angina exercise echocardiography
Chronic stable angina coronary angiography