Gallium-67 Single-Photon Emission Computed Tomography Affects Management of Infections of Left Ventricular Assist Devices

Abstract

Our institution employs gallium-67 single-photon emission computed tomography low-dose CT (Ga-SPECT-CT) to determine the presence and extent of left ventricular assist device (LVAD) infections. We present a retrospective single-center study of 41 LVAD recipients who underwent Ga-SPECT-CT from January 2011 to June 2018 to determine whether Ga-SPECT-CT led to changes in antimicrobial therapy, LVAD revision or exchange, or application for 1A exception. The average age was 56.6 years, predominantly male (80.5%) and diabetic (68.3%), divided between ischemic (48.8%) and nonischemic (51.2%) cardiomyopathy. The majority had HeartMate II devices (82.9%). Device-related infections were classified as possible (12.2%), probable (36.6%), proven (36.6%), or rejected (14.6%). Sensitivity was 68.6% and specificity was 100%. Most VAD-specific infections were percutaneous deep driveline infections (DRIs) (34.1%), and VAD-related infections were primarily bloodstream infections (31.7%). Staphylococcus aureus was the major pathogen isolated. Gallium-67 single-photon emission computed tomography low-dose CT resulted in changes in management in more than half (53.7%) of patients: starting (24.4%) or stopping (17.1%) antimicrobial therapy, LVAD revision (22.0%) or exchange (12.2%), and the application for 1A exception for transplant listing (17.1%). We conclude that Ga-SPECT-CT is an effective modality for determining the presence and extent of LVAD DRIs, and contributed to a change in management in more than half of cases.

LVAD decommissioning for myocardial recovery: Long-term ventricular remodeling and adverse events

“…For current patients being considered for LVAD decommissioning with a history of driveline infections (active or past infection), one approach to assess candidacy for decommissioning or complete explantation, is to pursue fluorine-18 flurodeoxyglucose (FDG) or gallium-67 single-photon emission computed tomography (Ga-SPECT-CT). 36,37 These imaging techniques have a high sensitivity and specificity for detecting infections involving the internal component of the driveline, pump, inflow cannula, and outflow graft. Patients with positive scans concerning for infection could then be counseled that complete device removal may be more appropriate than device decommissioning or should be considered for long-term suppressive antibiotic therapy if complete device explant is not feasible.…”

Infections in Patients With Left Ventricular Assist Devices: Current State and Future Perspectives

“…From an ionizing radiation standpoint, dose equivalents for Ga SPECT/CT and FDG-PET/CT are similar but increased compared with radiolabeled leukocyte imaging. 48 Although more research is needed to determine the optimal advanced imaging modality in VAD infections, the 2022 ISHLT update on MCS may support the use of FDG-PET/CT as a tool to guide treatment and prognosis at a class IIb recommendation.…”

Bring it on: Top five antimicrobial stewardship challenges in transplant infectious diseases and practical strategies to address them

“…66,67 Imaging to assist in diagnosis is not standardized and has limitations: Computed tomography has variable performance and is affected by device artifact, ultrasound detects only superficial fluid collections, and access to FDG-PET may be a barrier, 67 although gallium single-photon emission computed tomography (SPECT) appears to be a promising imaging modality. 68 Even if the extent of infection is successfully diagnosed, uncertainties remain regarding duration of therapy and the role of chronic antimicrobial suppression (CAS). The evidence for the current treatment duration recommendations for superficial and deep driveline infections is limited 64,67 and, in clinical practice, widely variable.…”