Occult bacteraemia in cardiac implantable electronic device patients: a review of diagnostic workflow and mandatory therapy

: Cardiac implantable electronic device (CIED) implantation has greatly increased, with an associated exponential increase in CIED infections (CDIs). Cardiac device related infective endocarditis (CDRIE) has high morbidity and mortality: approximately 10-21%. Therefore, a prompt diagnosis and radical treatment of CDRIE are needed; transvenous lead extraction (TLE) is the mainstay for the complete healing, even if associated with wide logistic problems, high therapeutic costs and high mortality risk for patients. Some criticisms about the value of Duke criteria and their limitations for the diagnosis of CDRIE are known. The significance of classic laboratory data, transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE), considered in the Duke score, are reviewed and critically discussed in this article, with regard to the specific field of the diagnosis of CDI. The need for new techniques for achieving the diagnostic reliability has been well perceived by physicians, and additional techniques have been introduced in the new European Society of Cardiology (ESC) and British Heart Rhythm Society (BHRS) guidelines on infective endocarditis. These suggested techniques, such as 18-Fluorodeoxyglucose PET/computed tomography (FDG-PET/CT), white blood cell PET (WBC PET) and lung multislice CT (MSCT), are also discussed in the study. This short review is intended as an extensive summary of the diagnostic workflow in cases of CDI and will be useful for readers who want to know more about this issue.

Starfix lead extraction: Clinical experience and technical issues

Transvenous lead extraction (TLE) of the Starfix coronary sinus (CS) active-fixation lead may be challenging, due to undeployment of fixation lobes and venous occlusion. We report our experience in Starfix TLE, in comparison with previous data. A 78-year-old male, implanted in 2009 with Starfix lead, was referred to our institution for TLE, due to infective endocarditis with lead-associated vegetations. The tip of Starfix lead was located in distant, anterior position, in the great cardiac vein, close to patent left internal mammary artery-to-left anterior descending artery anastomosis, and first-choice surgical removal had a prohibitive operative risk. Conventional dilatation beyond CS ostium, as well as the use of a standard delivery catheter, was ineffective. An off-label modification of the delivery, by cutting the distal soft tip, was successful. However, the tip of the lead fragmented and was trapped in the innominate vein. Then a gooseneck snare grasped the fragment, allowing complete retrieval. TLE of Starfix leads may be particularly challenging, especially when its tip is located in a distant anterior location. In these cases, important help may be obtained by dilatation within the CS, by means of conventional or modified delivery catheters. Only experienced operators, sometimes with non-conventional techniques, should perform TLE of Starfix leads. .

Analysis of extracted cardiac device leads for bacteria type: clinical impact

The use of cardiac implantable electronic devices (CIED) increased over time, followed by rise of CIED-related complications, mainly infections and malfunctions. A clear diagnosis of CIED infection is of pivotal importance. When infection is confirmed, transvenous lead extraction (TLE) becomes mandatory, with associated risks and mortality. Local lesions at the device pocket often return negative swabs and tissue specimens, but conservative interventions are inconclusive, raising risks of systemic dissemination of infection and difficulties of subsequent TLE any more. When local bacteriological analyses are positive, once again, a contamination effect cannot be excluded. So traditional local swabs and tissue specimens exhibit low sensitivity and specificity for diagnosis of CIED infection. On the contrary, in cases sepsis, blood samples show high specificity, while the sensibility remains low, due to possible negative results in patients on antibiotics. In this scenario, the analysis of extracted device leads seems more appropriate for diagnostic purposes.