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

Abstract

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.

Keywords: :

• bacteriology
• cardiac implantable electronic device infections
• cardiac device-related endocarditis
• diagnosis
• lead samples
• transvenous lead extraction

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• • Incidence and clinical issues related to cardiac implantable electronic devices (CIED) infections: over the last years, the incidence of pacemaker and defibrillator lead infections widely increased, with significant increase of hospitalizations and mortality.

• • How accurate may be the clinical diagnosis? Clinical presentation of CIED infections may be misleading. Chronic draining sinus in the great majority of cases hides an infection; and local infections are often associated with systemic involvement, mainly lead vegetations in a clinically unsuspected rate. Experts have accepted these concepts as a milestone, and local lesions have been regarded as mandatory indications to transvenous lead extraction.

• • Duke criteria for diagnosis of bacterial endocarditis exactly fit CIED infections? CIED infections seldom manifest themselves with systemic involvement, abnormal laboratory tests or lead vegetations. Therefore, Duke criteria are not perfectly reliable when applied to a suspected CIED infection.

• • Impact of lead samples for diagnosis in opposite conditions: chronic draining sinus and sepsis: positive tissue cultures, before lead extraction, leading to correct bacteriological diagnosis are infrequent. Swabs and tissue specimens from the CIED pocked often return negative results, and, on the contrary, isolates from local lesions may be due to a contamination effect. Lead samples increase diagnostic specificity, lowering the risk of contamination, and increase diagnostic sensibility. In cases of sepsis, positive blood cultures show high specificity, but sensibility may be low, particularly in patients on antibiotics and in the not uncommon cases of subacute course of the infection. Lead samples therefore increase diagnostic accuracy for CIED infections, with important incremental additive effect in association with blood samples.

• • Impact of lead samples for therapy, in the individual patient and from a population-related approach: bacteria associated with CIED infections exhibit a poor susceptibility to antibiotics, with significant increase of methicillin-resistant strains. In the individual patients, sensitivity results may drive an appropriate antibiotic therapy. From a population-based approach, knowledge of antibiotic resistances may change protocols for prophylaxis during CIED procedures and for first-line empiric antibiotic therapy, in cases of CIED infections.

Notes