Contributory Role of PET/CT in Diagnosis and Clinical Management of Infections in Patients Supported with a Continuous-flow LVAD

Purpose: The current study sought to demonstrate the advantages offered by PET/CT in patients supported with continuous-flow left ventricular assist devices (CF-LVADs) in detecting infection and the consequent impact on clinical decisions.

Methods: Between April 2009 and June 2015, 48 PET/CT examinations were performed in 37 patients (29 men, mean age 53.8 years ± 13.5 years) supported with a CF-LVAD. In group A (22 examinations), PET/CT was performed to detect infectious focus in patients without external signs of driveline involvement but with at least two of the following infection signs: recurrent fever, positive blood culture or elevated infectious parameters. In group B (26 examinations), PET/CT aimed to assess the internal extension of infection in patients with external signs of driveline infection.

Results: In 50.0% of the examinations in group A, abnormal 18F-FDG uptake was related to VAD components. Detection of infection included deep driveline infection in 6 patients and deep driveline infection with pump housing involvement in 5 patients. Matching the results with the final diagnosis, we reported nine true positive, eleven true negative, no false negative and two false positive findings. New information unrelated to VAD was found in eleven cases (50%): pneumonia in 4, abnormal colon uptake in 4, sternal dehiscence in one, paravertebral abscess in one and erysipelas in another case. In group B, superficial abnormal 18F-FDG uptake was found at the piercing site of the driveline in two patients, deeper extension of infection along the driveline in 11, initial involvement of the pump housing and full involvement of the device in 6 and 4 patients, respectively. These findings contributed to changing the clinical management in 81.8% and in 88.4% of the cases of group A and B, respectively: 17 patients were scheduled for urgent transplantation, 2 underwent surgical revision of the driveline, prolonged antibiotic therapy was needed in 8 and a colonoscopy was required in four cases.

Conclusion: This single-center experience highlights the diagnostic value of PET/CT in detecting the localization and internal extension of infection to internal VAD components. Moreover, this information notably influences the therapeutic management.