Clinical, Diagnostic and Therapeutic Aspects of Implantable Cardiac Electronic Device Infections. A Five-Year Retrospective Analysis and Comparison with Literature.

Background: Infections related to implantable cardiac electronic devices (IICEDs) are increasing in incidence. Aim of our study was to evaluate: epidemiological characteristics, risk factors and type of device in patients who developed ICEDs compared to the control group; b. microbial causes and resistances; c. main signs and symptoms, laboratory and instrumental investigations; d. treatment and prognosis. Material and Methods: the study was conducted with a retrospective method, analysing all cases of IICEDs registered in our ward from April 2009 to May 2014. For each patient, were evaluated epidemiological and clinical characteristics, risk factors, diagnostic procedures, aetiology and antibiotic assays, treatment and outcome. Results: In the investigated period, 22 cases of IICEDs were registered. Demographic factors didn’t affect the risk of ICEDs. Hypertension, usually considered a risk factor, resulted to be a protective factor (p=0.0329). Age younger than 65 years, female gender, altered BMI, diabetes, dyslipidemia and smoking appear to increase the risk of IICEDs, although not significantly. The oral anticoagulant therapy was found to be a predictive negative factor (p=0.0012) as well as the type of implanted device, with particular regard to intracardiac defibrillator and biventricular devices. CoNS were isolated in 68% of cases, Staphylococcus aureus in 25% and Enterococcus faecalis in 3.5%. A polimicrobial aetiology was registered in one case (3.5%). Among the CoNS, S. epidermidis was the most represented (28.55%), followed by S. hominis (14.3%) and S. haemoliticus (14.7%). The antibiotic assays showed a high proportion of methicillin resistance (34.8%) mainly related to S. epidermidis (71.4%) followed by S. aureus (14.3%). Rifampicin was found to be resistant in 8 cases (100%) by susceptibility testing. The treatment of ICEDs showed an important heterogeneity and a very long time waiting (12.22 months) between the diagnosis and the removal of the device. Of the 22 treated patients 7 died; 3 of them were older than 90 years while 4 were aged between 61 to 68 years. Conclusion: young age, smoking and altered BMI are factors associated to the development of IICEDs, even if not statistically significant. Hypertension resulted a statistically protective factor. The suspension of oral anticoagulation therapy and assumption of perioperative heparin was found to be statistically associated with the risk of IICEDs development, because it increases the risk of hematoma formation. According to literature data, the majority of the isolated microorganisms were Staphylococci (68% CoNS and 25% S. aureus) with high rates of methicillin (34.8%) and rifampicin (100%) resistance. The difference between systemic infections and infections localized to the generator pocket is not easily distinguishable, confirming the therapeutic need of the device removal in case of infection.