The concept of informed consent requires that risks and benefits of and alternatives to coronary angiography be explicitly discussed with the patient before the procedure is undertaken. Despite these shortcomings and potential complications, coronary angiography is useful to a) ascertain the cause of chest pain or anginal equivalent symptoms, b) define coro- nary anatomy in patients with high-risk noninvasive stress test findings (Section 3.3 in the 2012 full-text guideline) as a requisite for revascularization, c) determine whether severe CAD may be the cause of depressed left ventricular ejection fraction, d) assess for possible ischemia-mediated ventricular arrhythmia, e) evaluate cardiovascular risk among certain recipient and donor candidates for solid-organ transplantation, and f) assess the suitability for revascularization of patients with unacceptable ischemic symptoms (ie, symptoms that are not controlled with medication and that limit activity or quality of life). Coronary angiography may also be helpful when initial stress testing is inconclusive or yields conflicting results and definitive determination of whether IHD is present will result in important changes to therapy. The exclusion of epicardial CAD in a patient with recurring chest pain or other potential ischemic symptoms is particularly useful when it leads to more appropriate treatment, including withdrawal of medications. In a subset of patients, clinical characteristics, symptoms, and/ or results of noninvasive testing alone indicating a high likelihood ofmultivesselorleftmaindisease(eg,largeischemicburden)may prompt diagnostic angiography and revascularization, instead of initial stress testing. Patients with long-standing diabetes mellitus and end-organ damage, severe peripheral vascular disease (eg, abdominal aortic aneurysm), or previous chest (mantle) radia- tion therapy may have severe CAD particularly when ischemic symptoms are present.28 31 Patients with a combination of typical angina, transient heart failure, pulmonary edema, or exertional or unheralded syncope may have severe CAD. 