Contributory Role of Fluorine 18-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in the Diagnosis and Clinical Management of Infections in Patients Supported With a Continuous-Flow Left Ventricular Assist Device.

BACKGROUND: The current study sought to demonstrate the advantages offered by fluorine 18-fluorodeoxyglucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) in patients supported with continuous-flow left ventricular assist devices (CF-LVADs) in detecting infection and the consequent effect on clinical decisions. METHODS: Between April 2009 and September 2013, 40 PET examinations were performed in 31 patients (78.1% men; mean age, 51.0 ± 14.9 years) supported with a CF-LVAD. In group A (19 examinations in 14 patients), 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 indicators. In group B (21 examinations in 17 patients), PET/CT aimed to assess the internal extension of infection in patients with external signs of driveline infection. RESULTS: In 50% of the cases of the patients in group A, abnormal (18)F-FDG uptake (9 patients) was related to VAD components. Matching the results with the final diagnosis, we reported 9 true-positive, 8 true-negative, no false-negative, and 2 false-positive findings. New information unrelated to VAD was found in 9 patients (50%): pneumonia in 3, colon diverticulitis in 3, sternal dehiscence in 1, paravertebral abscess in 1, and erysipelas in 1. In group B, superficial abnormal (18)F-FDG uptake was found at the piercing site of the driveline in 2 patients, deeper extension of infection along the driveline in 10, initial involvement of the pump housing in 2, and full involvement of the device in 4. These findings contributed to changing the clinical management in 84.2% of group A patients and in 85.7% of group B patients: 16 patients were scheduled for urgent transplantation, 2 underwent surgical revision of the driveline, 7 required prolonged antibiotic therapy, and 3 underwent colonoscopy. CONCLUSIONS: 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.

Is Implantation of a Left Ventricular Assist Device in Patients With Critical or Impending Cardiogenic Shock an Absolute Contraindication? Looking Back at Our Past Experience Trying to Identify Contraindicative Risk Factors.

Poor survival has been demonstrated after ventricular assist device (VAD) implantation for Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) profile 1 and 2 patients compared with more stable levels. However, risk factors within this high-risk cohort have not been determined so far. The aim of the present study was to identify risk factors associated with this very high mortality rate. Between February 1993 and January 2013, 298 patients underwent VAD implantation in our institution. One hundred nine patients were in INTERMACS level 1 and 49 patients were in INTERMACS level 2 and were therefore defined as hemodynamically critical (overall 158 patients). Assist devices implanted were: HVAD HeartWare n = 18; Incor n = 11; VentrAssist n = 2; DeBakey n = 22; and pulsatile systems n = 105. After cumulative support duration of 815.35 months, Kaplan-Meier analysis revealed a survival of 63.9, 48.8, and 40.3% at 1, 6, and 12 months, respectively. Cox regression analyses identified age > 50 (P = 0.001, odds ratio [OR] 2.48), white blood cell count > 13.000/µL (P = 0.01, OR 2.06), preoperative renal replacement therapy (P = 0.001, OR 2.63), and postcardiotomy failure (P < 0.001, OR 2.79) as independent predictors of mortality. Of note, last generation VADs were not associated with significantly better 6-month survival (P = 0.59). Patients without the aforementioned risk factors could yield a survival of 79.2% at 6 months. This single-center experience shows that VAD implantation in hemodynamically unstable patients generally results in poor early outcome, even in third-generation pumps. However, avoiding the aforementioned risk factors could result in improved outcome.