Early detection of myocardial ischaemia in the emergency department by rest or exercise 99mTc tracer myocardial SPET in patients with chest pain and non-diagnostic ECG

Abstract

Chest pain (CP) represents a frequent reason for presentation at the emergency department (ED). A large proportion of patients have non-diagnostic ECG on presentation, and in many cases several hours have elapsed since onset of symptoms. Acute rest myocardial scintigraphy (rest SPET) has been shown to have a relevant role in the detection of patients at risk for coronary events, but its sensitivity and negative predictive value are optimal only within the first 3 h following onset of symptoms. In those with delayed presentation, exercise SPET alone, as a screening approach, appears more promising, but its feasibility and diagnostic role in the ED are still unresolved. A total of 231 consecutive patients with a recent-onset (<24 h) first episode of CP had a negative first-line work-up including ECG, troponins, creatine kinase-MB and echocardiography. These patients were considered at low risk for short-term coronary events. Patients were studied with rest SPET if they presented <3 h after onset of CP and exercise SPET if they presented after > or =3 h. The end-points of the study were detection of significant coronary artery disease (CAD) by angiography and major coronary events or cardiac death at 6 months. Eighty patients (35%) underwent rest SPET, while 151 (65%) underwent exercise SPET. Two of the 159 patients with negative SPET had evidence of critical CAD at 6-month follow-up (one patient in the rest SPET group and one in the exercise SPET group; P=NS). Of the 72 patients (31%) with a positive scan, 34 (15%) had documented CAD (16 patients in the rest SPET group and 18 in the exercise SPET group; P=NS). Sensitivity, specificity, accuracy and predictive value were not statistically different between the two groups. In conclusion, the accuracy of exercise SPET in patients with CP and delayed presentation to the ED is comparable to that of validated rest SPET in patients with early presentation. Owing to the high negative predictive value (99%), exercise SPET is especially valuable as a screening tool for the exclusion of CAD in low-risk patients and implementation of early discharge.

Evaluation of the diagnostic and prognostic use of gated myocardial perfusion single-photon emission computed tomography in patients with acute chest pain

“…c Statistically significant negative correlation with the SYNTAX score (P < 0.001). [21][22][23]. Our findings showed that R-GSPECT and S-GSPECT had high sensitivity, specificity, NPV, PPV, and accuracy for the diagnosis of ACS in the low-intermediate risk group, in agreement with the existing literature.…”

Evaluation of Acute Chest Pain in the Emergency Department

“…[21][22][23][24][25] The addition of stress imaging in stable patients improves diagnostic accuracy. 26 Although very useful for assessment of ischemic burden and planning future management, a normal SPECT does not exclude the presence of significant coronary disease. Balanced ischemia due to disease of all 3 major coronary arteries or the left main coronary artery may obscure qualitative detection of reduced perfusion, whereas attenuation artifacts may produce false-positive results.…”

Is Computed Tomography Coronary Angiography the Most Accurate and Effective Noninvasive Imaging Tool to Evaluate Patients With Acute Chest Pain in the Emergency Department?

“…54 However, according to current guidelines, most CPU order stress SPECT if serial 12-lead ECG and cardiac biomarker measurements are normal, which has been shown to improve diagnostic accuracy. 34,55 Conversion of nondiagnostic exercise studies (achieve Ͻ85% of maximal heart rate) to pharmacological stress (eg, adenosine) is recommended. A drawback to rest-stress SPECT studies is radiation exposure, which is estimated to average 11.3 mSv with sestamibi and 9.3 mSv with tetrofosmin and is greater than the exposure from most diagnostic invasive angiograms (average, 5 to 7 mSv).…”