Who Is a Candidate for Noninvasive Coronary Angiography?

Invasive coronary angiography is the gold standard for localizing stenoses in patients with suspected myocardial ischemia (1). Because this test is invasive and costly and has risks, professional organizations have defined indications for it (1). An expert panel gives a class I recommendation only when it finds strong evidence or general agreement of effectiveness, and the most recent guideline from the American College of Cardiology and the American Heart Association contains few class I indications (1). In patients with asymptomatic or stable angina and known or suspected coronary artery disease (CAD), the class I recommendations are for patients with severe grades of angina (Canadian Classification System classes III and IV) despite intensive medical treatment; patients who, regardless of angina severity, are at high risk for severe ischemia or sudden cardiac death according to noninvasive functional testing; and patients who survived an episode of sudden cardiac death or have a high-risk arrhythmia. Invasive coronary angiography is appropriate in each of these situations because of the high pretest probability of finding high-grade stenoses that will often result in a clinical recommendation for revascularization.

Class I recommendations for invasive coronary angiography also apply to some patients with nonspecific chest pain or unstable angina (1). In the patient with nonspecific chest pain (in whom the pretest probability of coronary stenoses would usually be low), a high-risk abnormality on noninvasive testing is a class I indication for invasive coronary angiography. Unstable angina is a class I recommendation because of the high pretest probability of a stenotic lesion, which led to revascularization in published studies.

To put the class I indications in an overall perspective, expert panels recommend invasive coronary angiography when there is a high probability of finding stenoses that require revascularization. Guidelines recommend noninvasive tests rather than invasive coronary …