Acute chest pain imaging in the outpatient setting

NUCLEAR CARDIOLOGY

BULLET

Acute chest pain imaging in the outpatient setting Jeffrey A. Rosenblatt, and Mylan C. Cohen,

MD, Linda Converse,

CNMT,

MD, MPH

Case hlstory. A 75year-old man was scheduled for an exercise stress test using technetium 99m sestamibi with single photon computed tomography (SPECT) for the evaluation of recurrent chest discomfort approximately 1 year after coronary artery bypass grafting. Saphenous vein grafts had been placed to an obtuse marginal branch and the right coronary artery; a left internal mammary artery graft had been placed to the mid-left anterior descending artery. When the patient arrived at the stress laboratory, he had anginal-like symptoms. His blood pressure was 156/78 mm Hg, and his heart rate was 68 beats/min. The electrocardiogram was without ischemic changes. Cllnical dilemma. A symptomatic patient with an unremarkable electrocardiogram was scheduled for stress perfusion scintigraphy. The dilemma was whether a stress test should be performed on a patient who may have ischemic symptoms or if an alternative method of arriving at a diagnosis and determining prognosis should be sought. Acute chest pain imaging with SPECT and Tc99m sestamibi has recently been demonstrated as an accurate and cost-effective diagnostic tool for risk stratification of selected patients arriving at the emergency department for the evaluation of chest pain.)*‘*3 Although the cohort of patients in previous acute chest pain imaging protocols included those who arrive at the emergency department, acute imaging is also applicable in the outpatient setting. Therefore we elected to perform a rest perfusion scan without stress in this symptomatic individual. He was injected with 23 mCi of Tc-99m sestamibi, and images were obtained while he was at rest. Results of nuclear myocardial perfusion imaging showed From the Department of Nuclear Cardiology, Maine Cardiology Associates, and the Division of Cardiology, Maine Medical Center, Portland, Maine. Reprint requests: Jeffrey A. Rosenblatt, MD, Maine Cardiology Associates, 66 Bramhall St, Portland ME 04102; [email protected]. J Nucl Cardiol 2000;7: I90- I. Copyright 0 2000 by the American Society of Nuclear Cardiology. lO71-3581/2000/$12.00 + 0 43/l/102597 doi: 10.1067/mnc.2000.102597

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RT(N), Debbie Hunter,

Figure I. Top, Tc-99m sestamibi SPECT myocardial perfusion images of patient with pain at rest demonstrating large, severe lateral defect. Bo//orn. Exercise Tc-9Ym sestamibi SPECT image of same patient I month after successful percutaneous revascularization with a same-day, rest-stress protocol. The large, lateral defect has nearly completely normalized on both stress and rest images

a large, dense inferoposterior perfusion defect in the territory of the obtuse marginal graft (Figure 1). Cllnlcal course. Based on the stress results, the patient was hospitalized and taken to the cardiac catheter-

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maximum heart rate (10 metabolic equivalents) without angina. Stress and rest images showed near complete normalization of the prior defect (Figure 1). Concluslon. Acute SPECT imaging with Tc-99m sestamibi is an emerging, cost-effective stratagem for selected patients arriving at the emergency department with chest pain. To date, the cohort of patients studied have included those who arrive at the emergency department with typical chest pain and a normal or nondiagnostic electrocardiogram. This application could be extended to other clinical settings. The current case demonstrates that in an outpatient setting, a severe rest SPECT perfusion defect in a symptomatic patient with a nondiagnostic electrocardiogram prompted timely hospitalization and revascularization. The resting defect was consistent with jeopardized, viable myocardium as it normalized after revascularization. Figure 2. Coronary angiogram of patient with patent circumflex vein graft but high-grade stenosis in a segment connecting a large marginal branch. ization laboratory. All grafts were patent; however, a high-grade stenosis in a segment connecting 2 obtuse marginal branches distal to the revascularized branch was present (Figure 2). Successful rotoblation and stent deployment were performed on the following day. He was rendered symptom-free. One month later, stress testing with Tc-99m sestamibi SPECT was performed. He exercised to a peak heart rate of 145 beats/min, reaching 100% of predicted

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3. Tatum JL. Cost effective nuclear scanning in a comprehensive and systematic approach to the evaluation of chest pain in the emergency department. Md Med J 1997;suppl:25-9.