Late gadolinium enhancement and viability / Nuclear imaging 975 P4695 Prognostic value of global circumferential strain as assessed by feature-tracking cardiac magnetic resonance in patients with a first st-segment elevation myocardial infarction G. Nucifora 1 , D. Muser 2 , C. Tioni 2 , R. Shah 3 , J. Selvanayagam 3 . 1 University Hospital of South Manchester NHS Foundation Trust, Manchester, United Kingdom; 2 University Hospital Santa Maria della Misericordia, Udine, Italy; 3 Flinders Medical Centre and Flinders University, Adelaide, Australia Background: Several CMR techniques have emerged that permit to directly as- sess myocardial deformation, which has been demonstrated to be more closely related to myocyte metabolism and contractility than LVEF. Among these tech- niques, CMR feature-tracking has gained prominence as a fast and accurate modality for the assessment of LV strain. However, it is still unknown whether CMR assessment of myocardial strain provides independent and incremental prognostic information in patients with STEMI. The aim of the present study was to investigate the prognostic utility of feature-tracking derived global circumferen- tial strain (GCS) in patients admitted with a first STEMI. Methods: 180 consecutive patients admitted because of a first STEMI and re- ferred to CMR with LGE imaging were included. All patients underwent immedi- ate coronary angiography and primary PCI. CMR studies were performed using a 1.5T scanner after a median of 8 days following the index event. Cine-CMR and LGE images were analysed offline to assess LV volumes, EF, infarct size (IS) and microvascular obstruction (MVO). The endocardial LV contours from cine-CMR basal, mid and apical short-axis images were analysed offline to derive GCS using 2D Cardiac Performance Analysis Software. Patients were followed-up for a median duration of 95 months. The outcome event was a composite endpoint, which included 1) cardiovascular death; 2) aborted sudden cardiac death, defined as a nonfatal episode of ventricular fibrillation or sustained ventricular tachycardia requiring external cardioversion or appropriate ICD therapy; and 3) hospitalization for heart failure. Results: The mean age of the study population was 60±12 years and 72% were male. Mean LVEDV index was 83±20 ml/m 2 and mean LVEF was 50±13%; me- dian infarct size was 13% (interquartile range, 5 to 30%) and 31% had MVO. Mean GCS was -16±5%. During follow-up, 40 (22%) patients experienced at least 1 event. At Kaplan-Meier analysis, the risk of outcome event increased significantly with worsening tertiles of GCS (log-rank p<0.001), increasing tertiles of IS (log- rank p<0.001) and with the presence of MVO (log-rank p<0.001). After adjust- ment for clinical and CMR imaging characteristics having univariate association with the outcome event at p≤0.05, GCS remained significantly and independently associated with the outcome event (HR 1.17 per %; 95% CI 1.03–1.33; p=0.013). Of note, a significant increase of global X2 was observed when adding GCS to a model including clinical and non-contrast CMR variables (X2 change = 15.3; p<0.001) and to a model including clinical, non-contrast and LGE variables (X2 change = 5.7; p=0.017). Conclusion: LV GCS assessed by CMR feature-tracking can predict a worse long-term prognosis in patients admitted with a first STEMI and treated with PCI. More importantly, the predictive ability of GCS was incremental to other clinical and especially CMR variables, including IS and MVO. NUCLEAR IMAGING P4696 Diagnostic profile of 99mTc-HMPAO-labeled leukocyte SPECT/CT in assessment of cardiac device-related infective endocarditis K. Holcman 1 , M. Kostkiewicz 2 , W. Szot 3 , P. Rubis 1 , B. Malecka 4 , A. Zabek 4 , A. Lesniak-Sobelga 1 , M. Hlawaty 1 , K. Boczar 4 , S. Wisniowska-Smialek 1 , P. Podolec 1 . 1 Jagiellonian University Medical College, John Paul II Hospital, Department of Cardiac and Vascular Diseases, Kraków, Poland; 2 Jagiellonian University Medical College, Department of Cardiac and Vascular Diseases, Departament of Nuclear Medicine John Paul II Hospital, Krakow, Poland; 3 Jagiellonian University Medical College, Department of Hygiene and Dietetics, Departament of Nuclear Medicine John Paul II Hospital„ Krakow, Poland; 4 Jagiellonian University Medical College, Department of Electrocardiology John Paul II Hospital, Krakow, Poland Background: Single photon emission tomography and computed tomogra- phy with technetium99m-hexamethylpropyleneamine oxime–labeled autologous leukocytes (99mTc-HMPAO-SPECT/CT) is a promising technique in patients with suspected infective endocarditis (IE). However, the data on its diagnostic value in cardiac device-related infective endocarditis (CDRIE) are limited. Purpose: The aim of this prospective study was to assess 99mTc-HMPAO- SPECT/CT diagnostic accuracy in evaluation of CDRIE suspicion. Methods: We enrolled 60 consecutive patients (20 females, 40 males, mean age: 58±17,7 y.o., mean left ventricle ejection fraction value: 48±18%) with suspected CDRIE since June 2015 till July 2017. Patients undergone clinical evaluation, lab- oratory tests including blood cultures and transthoracic echocardiography (TTE) for assessment of IE associated lesions. Subsequently all patients had 99mTc- HMPAO-SPECT/CT (dose of 370–740 MBq), including two scans performed af- ter intravenous tracer injection. Exams were evaluated for presence and location of increased radioactivity foci, which reflect current accumulation of radiolabeled leukocytes in inflammatory sites. Exams were classified as positive for IE in case of presence of at least one intracardiac focus of abnormal tracer uptake or involv- ing cardiac implantable device electrodes. If radioactivity foci were localized solely within the lodge, 99mTc-HMPAO-SPECT/CT was classified as local cardiac im- plantable device infection (LDI). Patients were followed for 6 months, including TTE. Results: Overall 36 patients had pacemakers, 14 had implantable cardioverter defibrillators, 9 had resynchronization therapy, 1 had an epicardial lead and 10 had prosthetic cardiac valves. Mean laboratory values were: C-reactive protein 53±79 mg/ml, procalcitonin 1,55±5,80 ng/ml. TEE was positive for IE in 39 cases. Final diagnosis of infection was established in 24 (40%) patients. IE was diag- nosed in 19 patients – 14 had CDRIE, 1 had native valve IE (NVE), 4 had con- comitant prosthetic valve IE (PVE) and CDRIE. LDI was diagnosed in 5 patients. The most common pathogens causing IE were Enterococci and Staphylococci. There were 27 (45%) of 99mTc-HMPAO-SPECT/CTs classified as positive for IE or LDI. Scintigraphy exams showed: 19 CDRIE, 2 NVE, 2 PVE, 1 concomitant PVE and CDRIE, 3 LDI. Extracardiac inflammatory foci were found in 41,5% of patients, with most common localization in digestive system. Overall 99mTc-HMPAO-SPECT/CT was characterized by 82% accuracy (95% CI: 70–90%) and 0,63 Cohen’s kappa coefficient. 99mTc-HMPAO-SPECT/CT had 83% sensitivity, 81% specificity, 88% negative predictive value, 74% positive pre- dictive value. Conclusions: In patients with suspected cardiac device related infections 99mTc-HMPAO-SPECT/CT provides high diagnostic accuracy, whereas negative 99mTc-HMPAO-SPECT/CT excludes IE with high probability. 99mTc-HMPAO- SPECT/CT seems to be useful technique in CDRIE diagnostic pathway. Funding Acknowledgements: Grant from the Jagiellonian University Medical College P4697 Multi-center clinical evaluation of a precision-controlled rubidium-82 elution system for PET myocardial perfusion imaging J.M. Renaud 1 , A. Guo 1 , K. Gulenchyn 2 , M. Trottier 3 , J. Abele 4 , F. Harel 5 , R.S.B. Beanlands 1 , R.A. Dekemp 1 . 1 University of Ottawa Heart Institute, National Cardiac PET Centre, Ottawa, Canada; 2 St Joseph’s Healthcare Hamilton, Department of Nuclear Medicine, Hamilton, Canada; 3 Institut Universitaire de Cardiologie et de Pneumologie de Québec, Department of Nuclear Medicine, Québec, Canada; 4 University of Alberta Hospital, Department of Radiology & Diagnostic Imaging, Edmonton, Canada; 5 Montreal Heart Institute, Department of Nuclear Medicine, Montreal, Canada Introduction: Rubidium-82 (Rb-82) PET myocardial perfusion imaging (MPI) is gaining widespread use due to its superior diagnostic accuracy and its availability without the need for an onsite cyclotron. Rb-82 cardiac PET also enables evalua- tion of myocardial flow reserve and left ventricular ejection fraction at peak stress, further enhancing patient management with very low radiation exposure. For opti- mal MPI and added myocardial blood flow (MBF) quantification with low test-retest variability, eluted Rb-82 activity profiles should be accurate, precise and delivered consistently over a relatively short time interval. For patient safety, elutions must be free of breakthrough of the long-lived parent isotope strontium-82 (Sr-82), and Sr-85. We evaluated the performance of a commercial Rb-82 elution system us- ing constant-activity-rate infusions for PET MPI at different imaging centers. Methods: The performance of six Rb-82 elution system units (RUBY-FILL) was evaluated at five PET imaging sites over a 2-year period (1,300 cumulative days of use). N=6,582 patients underwent rest-stress MPI (total = 13,164 scans) with weight-based infusions of 10 MBq/kg. A standard 30s square-wave “constant- activity” infusion, unique to this device, was used to allow for additional flow quan- tification with 3D dynamic PET imaging. Automated quality control (QC) measure- ments of Rb-82 yield and Sr breakthrough detection limit values were recorded daily from which precision was estimated. For the patient elutions, bias and pre- cision of the requested vs. delivered activity (MBq) and elution time (s) were de- Downloaded from https://academic.oup.com/eurheartj/article/39/suppl_1/ehy563.P4697/5082206 by guest on 14 June 2022