Inflammatory volume from F-18-Fluorodeoxyglucose (FDG)-PET/CT assists in prognostic assessment of patients with left ventricular assist device (LVAD) infection

Abstract

644 Objectives: In analogy to tumor volume, inflammatory volume (IV) can be obtained by threshold analysis of F-18-FDG-PET/CT in patients with LVAD infection, in order to describe the extent of infection. We sought to determine its practical value. Methods: 50 LVAD-carrying patients with advanced infection underwent whole-body F-18-FDG-PET/CT. IV was defined as volume of elevated FDG uptake in cm3, for the total device, for outer components (OC, subcutaneous parts and driveline entry) and internal device components (DC, pump pocket and outflow tract). Follow-up was obtained for 4 years after PET/CT, and deaths were recorded. Results: Systemic levels of c-reactive protein (CRP) correlated significantly with DC IV (r=0.3122, p=0.027), but not with OC IV (r=-0.1761, p=0.2212). During 4-year-follow-up 31 patients were reported to be deceased. CRP (mg/l) at the time of PET was significantly higher in patients who died (30.5±7.744 vs 10.87±3.658 for survivors; p=0.005). DC IV was not different (35.69±25.39 vs 26.33±20.23 for survivors; p=0.2116). Kaplan-Meier survival analysis revealed a significant difference between patients above and below the CRP median (p=0.022). Of note, if patients were subdivided into groups based on CRP and DC IV (CRP over/under 10.3 mg/l and levels of IV over/under 27.12 cm3), the subgroup with high CRP and high DC IV had significantly lowest survival (p<0.0001). Conclusions: Infection volume from FDG-PET/CT provides diagnostic and prognostic information in LVAD infection. Internal device component involvement is correlated with CRP level, and combination of both parameters identifies a patient subset at highest risk of adverse outcome.