Prognostic value of normal stress-only technetium-99m myocardial perfusion imaging protocol. Comparison with standard stress-rest protocol.
BACKGROUND
Patients with a normal stress image on technetium-99m (Tc-99m) single-photon emission computed tomography (SPECT) have a good prognosis for diagnosing coronary artery disease. However, current guidelines recommend stress and rest imaging to confirm that a stress image is normal.


RESULTS
We determined all-cause of cardiac events (acute coronary syndrome and sudden death) in 1,939 patients undergoing stress myocardial perfusion SPECT with Tc-99m radiotracers. Patients with an abnormal stress image were excluded, so we focused on 1,125 patients in whom the stress SPECT study was interpreted as normal. A stress-only protocol was used in 726 patients (adenosine=339; exercise=387), whereas 399 had both stress and rest imaging (adenosine=294; exercise=105). Mean follow-up was 1,252 days. At the end of follow-up, there were 39 cardiac events in the stress-only cohort and 19 in the stress-rest cohort. Kaplan-Meier analysis revealed that there were no differences for the entire cohort of cardiac events not only between the stress-only and stress-rest protocols but also for stressor modality, despite the fact that the stress-rest cohort showed higher coronary risk factors.


CONCLUSIONS
Patients determined as having a normal SPECT on the basis of stress imaging alone have a similar cardiac event rate as those who have a normal SPECT on the basis of evaluation of both stress and rest images. This imaging strategy will significantly reduce radiation exposure in a substantial number of patients.
Division of Cardiology, Department of Medicine II, Kansai Medical University, Hirakata, Japan.
Takanao
T
Ueyama
Kazuya
K
Takehana
Hirofumi
H
Maeba
Toshiji
T
Iwasaka
D054058:Acute Coronary Syndrome / Q000000981:diagnostic imaging / Q000401:mortality; D000368:Aged; D003645:Death, Sudden; D018572:Disease-Free Survival; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D011849:Radioactive Tracers; D011859:Radiography; D015996:Survival Rate; D013667:Technetium / Q000008:administration & dosage*; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
D011849:Radioactive Tracers; D013667:Technetium