Abstract 5827: Prognostic Value of Post-Ischemic Stunning as Assessed by Gated Myocardial Perfusion SPECT: A Sub-Analysis of the J-ACCESS Study
Although post-ischemic myocardial stunning as assessed by ECG-gated myocardial SPECT has emerged recently as an important marker for severe CAD, its prognostic value has not been evaluated. To determine the prognostic value of post-ischemic stunning using 99mTc-tetrofosmin gated myocardial SPECT, the database of the J-ACCESS study was reevaluated. Among 4031 patients of the J-ACCESS cohort, the current study evaluated 1089 patients who completed gated SPECT both after stress and at rest to reveal the development of post-ischemic stunning. Patients who underwent coronary revascularization within 3 months after the SPECT study were excluded. They were aged 66± 10 years; 652 were men. Using a 20-segment model, a summed stress score (SSS) and other scores were assessed. To assess post-ischemic stunning, the following measurements (LV volumes after stress minus volumes at rest) were made: ΔESV, ΔEDV and ΔEF. Cardiac events were defined as cardiac death, nonfatal MI, severe heart failure requiring hospitalization, PCI and CABG. Myocardial stunning defined either as ΔESV≥5 ml, ΔEDV≥5 ml or ΔEF≤−5% were observed in 21%, 22%, or 26%, respectively. During the 3-year follow-up, 101 cardiac events were observed. Kaplan-Meier survival estimation indicated event-free survival rates at 3 years of 81%, 83%, 72%, 88% and 89%, respectively in patients with dilated ESV, dilated EDV, LVEF≤45%, ΔESV≥5 ml and ΔEDV≥5 ml, but 94%, 93%, 93%, 94% and 93%, respectively in those without (p< 0.0001, p< 0.002, p< 0.0001, p< 0.02 and p< 0.03; respectively). However, ΔEF≤ −5% or SSS≥9 did not predict subsequent cardiac events. Multivariate analysis using the Cox proportional hazard model demonstrated that LVEF≤45% was the only independent predictor for subsequent cardiac event. Nevertheless, ΔEDV≥5 ml was also an independent parameter, in addition to LVEF≤45%, to predict the combined endpoint consisting of cardiac death, nonfatal MI, PCI and CABG, but excluding heart failure. These results indicate that post-ischemic stunning as assessed by gated SPECT is regarded as a marker for poor prognosis, particularly for ischemic cardiac events, and may have a role in risk stratification for patients with known or suspected CAD.