Resting Radionuclide Myocardial Perfusion Imaging in a Chest Pain Center Including an Overnight Delayed Image Acquisition Protocol

Abstract

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. Conclusion: 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. Pat ients often present to the emergency department (ED) with a complaint of chest pain (CP) and a nondiagnostic 12-lead electrocardiogram (ECG). Management decisions with these patients are difficult. Patients with noncardiac CP or low-risk angina can be safely discharged from the ED with appropriate follow-up (1). Rarely, patients with true unstable angina (UA) or myocardial infarction (MI) are discharged from the ED with potentially dire consequences (2). Standard initial diagnostic evaluation lacks sufficient sensitivity for UA (2); therefore, many lowrisk patients are admitted, resulting in significant cost to the health care system. Resting myocardial perfusion imaging (MPI) using 99m Tc with gated SPECT has been shown to provide information for risk-stratification of this population beyond the standard evaluation (3-6). In this setting, radionuclide MPI has demonstrated favorable test characteristics, including a high negative predictive value for cardiac events (3,7,8). Furthermore, MPI in the ED has been shown to be useful for clinical decision making (7-10) and to provide further information beyond that provided by serum biomarkers, including troponin (11). Rest MPI results also have short and intermediate prognostic implications in this setting (12,13). The ability to offer...

Gated-SPECT myocardial perfusion imaging and coronary calcium score for evaluation of patients with acute chest pain and a normal or nondiagnostic electrocardiogram

“…Our results are within the reported range: from 46% of abnormal MPI (30 of 64 patients) [10], to 16% with abnormal perfusion and 15% equivocal [11], to only 9% (45 of 479 patients) [14]. Our results are within the reported range: from 46% of abnormal MPI (30 of 64 patients) [10], to 16% with abnormal perfusion and 15% equivocal [11], to only 9% (45 of 479 patients) [14].…”

“…Acute rest myocardial perfusion imaging (MPI) in patients with suspected ACS has a high negative predictive value to exclude MI, as well as future cardiac events during medium-term follow-up (FU) [10][11][12][13][14]. Thus, in general, patients with normal acute rest MPI do not need to be hospitalized, avoiding unnecessary expenses.…”

Validation of the new Vancouver Chest Pain Rule in Asian chest pain patients presenting at the emergency department

“…20 As many hospitals face situations with decreased inpatient capacity resulting in "bed block," 21 management of chest pain in the ED can possibly decrease in-hospital admissions for evaluation of chest pain. 22 However, the pressures of ED overcrowding 21,[23][24][25][26][27][28] mean that ED resources can become stretched due to the lengthy and costly evaluations of chest pain patients in order to "rule out" ACS.…”

Uso da cintilografia miocárdica em repouso durante dor torácica para descartar infarto agudo do miocárdio

“…Some studies even mention that optimal sensitivity of troponin is not reached before 18 hours of symptom onset [13][14][15][16][17][18] . In our study, we found that Troponin I measurements at admission had a sensitivity of 68.8% compared to a 86% sensitivity of scintigraphy during chest pain.…”