Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology Additional value of systolic wall thickening in myocardial stunning evaluated by stress-rest gated perfusion SPECT Alberto Bestetti1, B. Cuko2 , A. Decarli3 , Alessio Galli4, Federico Lombardi41 1Department of Clinical and Biomedical Sciences, University of Milan; Service of Nuclear Medicine, IRCCS Multimedica Sesto San Giovanni, Milan, Italy; 2 School of Specialty in Nuclear Medicine, University of Milan, Milan, Italy; 3 Department of Clinical and Community Sciences, University of Milan, Milan, Italy; 4 Cardiovascular Diseases Unit, IRCCS Ca' Granda Major Hospital of Milan, University of Milan, Milan, Italy. Institution Picture/Logo Optional Professor Alberto Bestetti, M.D. Copyright American Society of Nuclear Cardiology

Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology BACKGROUND 1- Stress-rest gated SPECT is a valuable tool for assessing myocardial perfusion and function in ischemic patients. 2- Myocardial stunning is a phenomenon of reversible contractile dysfunction caused by coronary hypoperfusion during stress. Revascularization is generally indicated when myocardial stunning is present. 3- It is debated which is the best parameter to define myocardial stunning, whether wall thickening summed difference score (WT-SDS) or the variation in left ventricular ejection fraction with exercise (∆LVEF). Copyright American Society of Nuclear Cardiology

METHODS Study type: retrospective. Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology METHODS Study type: retrospective. Study subjects: 91 ischemic patients (82 males; mean age 59.7 ± 10.3), with coronary artery disease documented by angiography. Ischemia was defined as a summed difference score ≥ 5 at stress-rest gated SPECT. Study endpoints: Primary end point: to evaluate the correlation between ∆LVEF and WT-SDS. Secondary end point: to identify the best independent parameter correlated with myocardial ischemia. Study variables: - Perfusion: summed stress score, summed rest score, summed difference score. - Function: wall thickening summed stress score, wall thickening summed rest score, wall thickening summed difference score, left ventricular ejection fraction (LVEF), ∆LVEF, end-diastolic and end systolic volumes. Copyright American Society of Nuclear Cardiology

Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology RESULTS Figure 1A. This figure shows the good inverse linear correlation between WT-SDS and ∆LVEF (RHO=-0.33, p=0.002). Copyright American Society of Nuclear Cardiology

Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology RESULTS Figure 1B. This figure shows a good linear correlation between SDS and WT-SDS (RHO= 0.32, p=0.002). Copyright American Society of Nuclear Cardiology

Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology CONCLUSIONS 1- In ischemic patients post-stress left ventricular function is significantly lower than at rest (ΔLVEF -2.2 ± 4.8, p = 0.0001; WT-SDS 4.44 ± 4.13, p = 0.0001): this is the stunning phenomenon. 2- At multivariate analysis WT-SDS, and not ΔLVEF, is significantly correlated with the degree of myocardial ischemia (SDS). However, there is an inverse linear correlation between WT-SDS and ΔLVEF. 3- Patients divided according to the severity of ischemia (< 8 or ≥ 8 SDS) show significantly different values of WT-SDS, but not ΔLVEF. 4- WT-SDS should be evaluated in all patients with suspected myocardial stunning candidates to revascularization. Copyright American Society of Nuclear Cardiology