Myocardial ischemic reduction evidenced by gated myocardial perfusion imaging after treatment results in good prognosis in patients with coronary artery disease

Background: There are no nuclear cardiology reports indicating the prediction of prognosis based on ischemic reduction after revascularization in Japanese patients with coronary artery disease (CAD). We aimed to evaluate quantitatively ischemia using myocardial perfusion single photon emission computed tomography (SPECT) before and after treatment such as revascularization and to determine a relationship between the ischemic reduction and the incidence of major cardiac events (MCEs) after the treatment in patients with CAD. Methods: We retrospectively investigated 513 patients who underwent rest ²⁰¹Tl and stress ^99mTc-tetrofosmin myocardial perfusion SPECT between October 2004 and March 2011 and who had a significant stenosis with 75% or greater narrowing of the coronary arterial diameter detected by coronary angiography performed after confirmation of ≥5% ischemia with SPECT. The patients underwent the treatment including revascularization and medication and thereafter were re-evaluated with SPECT during a chronic phase and followed up to confirm prognosis for ≥1 year. The follow-up period was 33.4±16.4 months. The endpoint was the incidence of the MCEs consisting of cardiac death, non-fatal myocardial infarction, and unstable angina pectoris. Results: During the follow-up, 45 patients experienced MCEs comprising cardiac death (n = 13), non-fatal myocardial infarction (n = 3), and unstable angina pectoris (n = 29). The multivariate Cox proportional hazards regression model analysis for the risk of the MCEs showed the changes in the summed difference score % (p = 0.0102) and the stress left ventricular ejection fraction after the treatment (p = 0.0146) as significant independent variables. The incidence of the MCEs significantly decreased in the patients with ≥5% ischemic reduction than in the patients without ≥5% ischemic reduction and in the patients without residual ischemia than in the patients with the residual ischemia. Conclusion: Myocardial ischemic reduction detected by nuclear cardiology leads to a decrease in MCE rates after treatment in Japanese patients with CAD.