Patient #1 was a 64-year-old woman with chest discomfort provoked by exertion and emotional stress. Her pain was typically relieved by rest or sublingual nitrates. She was taking a β-blocking agent for hypertension. A physician judged her pain to be typical angina, and the degree of pain was evaluated as Canadian Cardiovascular Society (CCS) class 2. An exercise electrocardiogram (ECG) was inconclusive because the patient had limited work capacity due to osteoarthritis. The patient was referred for coronary angiography. As part of an observational study on the potential benefit of myocardial perfusion scintigraphy (MPS) as a gatekeeper for invasive procedures, MPS (with adenosine stress) was performed prior to angiography and showed normal perfusion (Figure). The result was not communicated to the referring physician and, thus, did not influence referral to angiography or choice of treatment. Based on the findings from coronary angiography, obstructive coronary artery disease was excluded. Treat­ment with a calcium antagonist was recommended, as small vessel disease could not be excluded.

Patient #2 was a 66-year-old man with symptoms almost identical to patient #1, that is, typical angina and CCS class 2 pain. He, too, was taking a β blocker because of hypertension. At rest, an ECG showed left bundle branch block, and his angiogram showed significant stenoses in the right coronary and left circumflex arteries. The results of MPS (with adenosine stress) performed before the angiography indicated reversible ischemia, as shown in the Figure. The patient was successfully revascularized with surgery.

These cases illustrate the potential use of MPS as a gatekeeper for angiography in 2 patients with very similar symptoms. MPS may avoid a substantial number of unnecessary invasive procedures and even guide therapy in patients with stable angina pectoris.