Usefulness of automated assessment of nuclear cardiology for prediction of major cardiac events in Japanese patients with known or suspected coronary artery disease: Comparison with conventional visual assessment in a large-scale prognostic study

Background: There are no reports indicating that automated quantification with a total perfusion deficit (TPD) is used to predict future cardiac events in Japanese patients. We, therefore, aimed to determine the prognostic value of the automated assessment with the TPD for risk stratification of major cardiac events (MCEs) in Japanese patients with known or suspected coronary artery disease (CAD). Methods: We retrospectively investigated 2848 patients who underwent rest ²⁰¹Tl and stress ^99mTc-tetrofosmin myocardial perfusion single photon emission computed tomography (SPECT) between October 2004 and March 2008. The follow-up period was 25.8±11.0 months. The TPD was automatically derived from the SPECT image through the QPS software with the Japanese normal database. Twenty segments of SPECT images were analyzed with the 5-point visual scoring model to estimate summed scores. The endpoint of the follow-up was the occurrence of MCEs within 1 year after the SPECT, which were identified with medical records or responses to a posted questionnaire. Results: During the first year of the follow-up, 62 patients had MCEs, which comprised cardiac death ( n= 30), non-fatal myocardial infarction ( n= 13), and unstable angina pectoris ( n= 19). The MCE rates positively correlated with the stress TPD and the summed stress score. Sensitivity of the automated quantification with the TPD for detection of the MCEs was high and similar to that of the visual semi-quantification. Multivariate Cox regression analysis indicated that significant independent predictors for the MCEs were an estimated glomerular filtration rate and the ischemic variables both in the automated quantification and visual semi-quantification. Conclusion: The automated quantification with the TPD is useful for prognostic risk stratification of MCEs in Japanese patients with known or suspected CAD. Its predictive power is similar to that of the visual semi-quantification by expert interpreters.