Resting radionuclide myocardial perfusion imaging in a chest pain center including an overnight delayed image acquisition protocol.
Emergency department (ED) patients with chest pain (CP) and a nondiagnostic electrocardiogram (ECG) present difficult management decisions. The purpose of this study was to investigate the utility of resting radionuclide SPECT myocardial perfusion imaging (SPECT MPI)-including an overnight delayed image acquisition protocol-in identifying patients presenting to the ED with CP at risk for cardiac events.


METHODS
Patients presenting to the ED with CP and a nondiagnostic ECG were prospectively enrolled and underwent chest pain center evaluation. All patients also underwent resting gated SPECT MPI using (99m)Tc-tetrofosmin tracer. Patients presenting on weeknights between 12 am and 6 am had tracer injection in the ED with image acquisition delayed until later in the morning. Patients were monitored for a 30-d occurrence of cardiac events.


RESULTS
Over a 16-mo period, 479 patients were enrolled and completed follow-up. For the prediction of 30-d cardiac events, resting SPECT MPI demonstrated a sensitivity and a specificity of 76.9% and 92.4%, respectively. Positive and negative predictive values were 22.2% and 99.3%, respectively. Among the 3 patients with a normal perfusion scan who suffered cardiac events, all had tracer injection several hours after resolution of CP. The overnight delayed image acquisition protocol provided a negative predictive value of 100% for the 44 patients whose image acquisition was delayed until the following morning.


CONCLUSIONS
A normal resting SPECT MPI in ED patients presenting with CP predicts a very low occurrence of 30-d cardiac events. A delayed image acquisition protocol did not decrease the accuracy of SPECT MPI. Such a protocol may be useful in increasing the availability of this imaging modality.
Schaeffer
Michael W
MW
Division of Cardiovascular Medicine, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, OH 45267, USA.
Brennan
Timothy D
TD
Hughes
Judith A
JA
Gibler
W Brian
WB
Gerson
Myron C
MC
D000208:Acute Disease / Q000453:epidemiology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002637:Chest Pain / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology; D004562:Electrocardiography; D005260:Female; D015637:Gated Blood-Pool Imaging; D006331:Heart Diseases / Q000150:complications / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009943:Organophosphorus Compounds / Q000493:pharmacokinetics; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics; D018710:Pain Clinics; D010477:Perfusion; D011868:Radioisotopes / Q000493:pharmacokinetics; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D012146:Rest / Q000502:physiology*; D018570:Risk Assessment; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013995:Time; D015899:Tomography, Emission-Computed, Single-Photon
D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D011868:Radioisotopes; D019275:Radiopharmaceuticals; C078700:technetium tc-99m tetrofosmin