Phage Therapy for Cardiac Implantable Electronic Devices and Vascular Grafts: A Targeted Literature Review

Infections of cardiac implantable electronic devices (CIEDs) and vascular grafts are some of the most dreaded complications of these otherwise life-saving devices. Many of these infections are not responsive to conventional treatment, such as systemic antibiotics and surgical irrigation and debridement. Therefore, innovative strategies to prevent and manage these conditions are warranted. Among these, there is an increasing interest in phages as a therapeutical option. In this review, we aim to collect the available evidence for the clinical application of phage therapy for CIED and vascular graft infections through literature research. We found 17 studies for a total of 34 patients. Most of the indications were left ventricular assist device (LVAD) (n = 20) and vascular graft infections (n = 7). The bacteria most often encountered were Staphylococcus aureus (n = 18) and Pseudomonas aeruginosa (n = 16). Clinical improvements were observed in 21/34 (61.8%) patients, with microbiological eradication in 18/21 (85.7%) of them. In eight cases, an adverse event related to phage therapy was reported. Phage therapy is a promising option for difficult-to-treat CIED and vascular graft infections by means of an individualized approach. Clinical trials and expanded access programs for compassionate use are needed to further unveil the role of phage therapy in clinical application.

Infective Endocarditis among Pediatric Patients with Prosthetic Valves and Cardiac Devices: A Review and Update of Recent Emerging Diagnostic and Management Strategies

Infective endocarditis (IE) is a disease of the endocardium, which leads to the appearance of vegetation on the valves, cardiac structures, or, potentially, vascular endothelium of the heart. The risk of IE can be increased more than 140 times by congenital heart disease (50-59% of all IE), particularly if cyanotic. An increase in mortality may result from IE in patients with a complex cardiac pathology or patients with an implanted prosthetic material, most frequently conduits in a pulmonary position. Cardiac implantable electronic devices (CIED) infective endocarditis is a life-threatening complication representing 10% of all cases of endocarditis. Common signs of presentation are often fever and chills; redness and swelling at the pocket of the pacemaker, including the erosion and exteriorization of the device; and life-threatening sepsis. The use of intracardiac echocardiography for the diagnosis of IE is an innovative method. This may be needed, especially in older children undergoing complex cardiac surgery, when transthoracic echocardiography (TTE) and transesophageal echocardiography (TOE) failed to provide a reliable diagnosis. The 2018 European Heart Rhythm Association (EHRA) experts' consensus statement on transvenous lead extraction recommends complete device removal and antimicrobial therapy for any device-related infection, including CIED-IE. The most detected microorganism was Staphylococcus Aureus. In addition, cardiac surgery and interventional cardiology associated with the placement of prostheses or conduits may increase the risk of IE up to 1.6% for Melody valve implantation. Our manuscript presents a comprehensive review of infective endocarditis associated with cardiac devices and prostheses in the pediatric population, including recent advances in diagnosis and management.

Economic impact of cardiac implantable electronic device infections: cost analysis at one year in a large U.S. health insurer

Aims: Cardiac device infections (CDIs) are serious adverse events associated with morbidity and mortality, significant costs and increased healthcare utilization. The objective of the current study was to characterize the CDI rate by device type, risk factors for infection and healthcare costs from a large U.S. health insurer perspective.Materials and Methods: A retrospective analysis of a large U.S. health insurer database identified commercial and Medicare Advantage with Part D (MAPD) members ≥18 years with ≥1 claim for a cardiac implantable electronic device (CIED) procedure between 01 October 2011 and 31 October 2015. CIEDs included pacemakers (IPG), implantable cardioverter defibrillators (ICDs), and cardiac resynchronization therapy - pacemakers without (CRT-P) and with defibrillation (CRT-D). Probabilities of CDI through one-year post implant were estimated using the Kaplan-Meier method. A regression model with stepwise variable selection was used to select risk factors associated with CDIs.Results: A total of 63,406 patients were included with an overall CDI rate of 1.28% (1.0% de novo and 1.74% replacement devices), varying by device type: IPG = 0.91%; ICD = 1.63%; CRT-p = 1.50%; CRT-D = 2.22%. The average adjusted annual medical costs were 2.4 times greater [95% confidence interval (CI) = 2.1-2.7] for those with an infection compared to those without, and the incremental cost difference was estimated to be $57,322 [95% CI $46,572-$70,484]. Observed risk factors of CDIs included prior device infection [Odds ratio (OR) = 11.356; 95% CI = 7.923-16.276], undergoing a CIED replacement procedure (OR = 1.644; 95% CI = 1.361-1.987), implantation of a high-power device (OR = 1.354; 95% CI = 1.115-1.643), and younger age (age < 65) (OR = 1.607; 95% CI = 1.307-1.976).Conclusions: The CDI rate at one year ranged from 0.91%-2.22% depending on device type. Management of CDIs among commercial and MAPD members is associated with high healthcare expenditures.

Detection of Biofilm-associated Implant Pathogens in Cardiac Device Infections: High Sensitivity of Sonication Fluid Culture Even in the Presence of Antimicrobials

Introduction:

Sonication showed more sensitivity than traditional culture in the diagnosis of device infections. Aims of the study were to assess the role of sonication in the microbiological diagnosis and management of cardiac device infections (CDIs), to evaluate the sensitivity of sonication in patients on antimicrobial therapy at the time of device removal, and to analyze biofilm formation of the isolated strains.

Materials and Methods:

A total of 90 devices (31 generators and 59 electrodes) collected from 31 patients with infection underwent sonication before culture. Devices were sonicated for 5 min and centrifuged at 3200 rpm for 15 min. Intraoperative traditional cultures were performed in 26 patients. Microorganisms were identified using conventional methods. Staphylococcal strains were tested for slime production.

Results:

Microbiological diagnosis was achieved in 28 patients (90%). Sonicate fluid was positive in 68/90 (76%) of devices (27/31 [87%] generators and 41/59 [69%] electrodes), whereas intraoperative pocket swabs grew bacteria in 10/26 patients (38%, P = 0.0007). Among leads, 37/59 (62.7%) yielded bacteria even in the absence of vegetation. Coagulase-negative Staphylococci accounted for 83.8% (57/68) of the total; Staphylococcus aureus and Gram-negative bacilli were found in 4.4% (3/68) and 5.8% (4/68), respectively. Biofilm production was present in 15/22 (69%) staphylococcal strains. Overall, patients on therapy (n = 23) had a microbiological diagnosis in 20/23 (86.9%) and 7/22 (30.4%) through sonication and intraoperative cultures, respectively (P = 0.0002).

Discussion:

Our data showed the high sensitivity of sonication in the diagnosis of CDIs, even in patients under antimicrobial therapy.

Conclusion:

Sonication represents an essential tool for both diagnosis and management of CDIs.