Genetic identification and risk factor analysis of asymptomatic bacterial colonization on cardiovascular implantable electronic devices

Risk factors for cardiac implantable electronic device infections: a nationwide Danish study

AIMS

Cardiac implantable electronic device (CIED) infection is a severe complication to modern management of cardiac arrhythmias. The CIED type and the type of surgery are recognized as risk factors for CIED infections, but knowledge of patient-related risk factors is scarce. This study aimed to identify lifelong patient-related risk factors for CIED infections.

METHODS AND RESULTS

Consecutive Danish patients undergoing a CIED implantation or reoperation between January 1996 and April 2018 were included. The cohort consisted of 84 429 patients undergoing 108 494 CIED surgeries with a combined follow-up of 458 257 CIED-years. A total of 1556 CIED explantations were classified as either pocket (n = 1022) or systemic CIED infection (n = 534). Data were cross-linked with records from the Danish National Patient Registry and the Danish National Prescription Registry. Using multiple-record and multiple-event per subject proportional hazard analysis, specific patient-related risk factors were identified but with several variations amongst the subtypes of CIED infection. CIED reoperations were associated with the highest risk of pocket CIED infection but also CIED type, young age, and prior valvular surgery [hazard ratio (HR): 1.62, 95% confidence interval (CI): 1.29-2.04]. Severe renal insufficiency/dialysis (HR: 2.40, 95% CI: 1.65-3.49), dermatitis (HR: 2.80, 95% CI: 1.92-4.05), and prior valvular surgery (HR: 2.09, 95% CI: 1.59-2.75) were associated with the highest risk of systemic CIED infections. Congestive heart failure, ischaemic heart disease, malignancy, chronic obstructive pulmonary disease, and temporary pacing were not significant at multivariate analysis.

CONCLUSION

Specific comorbidities and surgical procedures were associated with a higher risk of CIED infections but with variations amongst pocket and systemic CIED infection. Pocket CIED infections were associated with CIED reoperations, young age and more complex type of CIED, whereas systemic CIED infections were associated with risk factors predisposing to bacteraemia.

Clinical utility of sonication for diagnosing infection and colonization of cardiovascular implantable electronic devices

Our study aimed to evaluate the sensitivity of the sonication tool for the microbiological diagnosis of cardiovascular implantable electronic device infections (CIEDIs). The extracted cardiac implants of 52 patients were assessed: 19 with CIEDI and 33 with elective generator replacement or revision without clinical infection. Sonication fluid culture of explanted CIEDs yielded higher numbers of microorganisms than pocket tissue or swab cultures. The sensitivity of sonication fluid culture was significantly higher than that of pocket swab and tissue culture for microbiological diagnosis of CIEDI. The microorganisms isolated most frequently via sonication of explanted CIEDs were Gram-positive cocci (70%), of which 50% was coagulase-negative Staphylococcus. Sonication fluid culture detected colonization in 36.4% of the non-infected patients. Sonication fluid culture represents a promising diagnostic strategy with increased sensitivity compared to conventional culture methods for microbiological diagnosis of cardiac devices associated with infection and colonization.

Incidence of lead erosion in a real-world cohort and a case of successful treatment with an antimicrobial mesh

Cardiac implantable electronic device (CIED)-related infections are a major complication of CIED therapy and associated with high morbidity and mortality. The aim of the present study was to evaluate the incidence of lead erosion as one cause of the CIED-related infections and to provide detailed information about the therapy of two cases of lead erosion. We retrospectively screened the database of a large clinic specialized on patients with CIED (HIZ BERLIN Herzschrittmacher- und ICD-Zentrum, Berlin, Germany) for cases of lead erosion between 2015 and 2020. A total of 5971 outpatients were treated at the HIZ BERLIN - including 4782 patients with a one- or two-chamber pacemaker, 837 patients with an implantable cardioverter defibrillator (ICD) and 352 patients with a biventricular device for cardiac resynchronization therapy (CRT). The incidence of lead erosion was 0.033%. As one of the two patients, who suffered from lead erosions, had no signs of systemic infection, the patient received local therapy with an antimicrobial mesh and intravenous antibiotics. After twelve months, he showed a good clinical outcome without ongoing or recurring infection. In conclusion, the incidence of lead erosion is low. In case of lead erosions without signs of systemic infection, an antimicrobial mesh might be implanted as an off-label use in patients that decline complete device removal.

Risk Stratifying and Prognostic Analysis of Subclinical Cardiac Implantable Electronic Devices Infection: Insight From Traditional Bacterial Culture

Background

Subclinical infection of cardiac implantable electronic devices (CIEDs) is a common condition and increases the risk of clinical infection. However, there are limited studies focused on risk stratifying and prognostic analysis of subclinical CIED infection.

Methods and Results

Data from 418 consecutive patients undergoing CIED replacement or upgrade between January 2011 and December 2019 were used in the analysis. Among the patients included, 50 (12.0%) were detected as positive by bacterial culture of pocket tissues. The most frequently isolated bacteria were coagulase‐negative staphylococci (76.9%). Compared with the noninfection group, more patients in the subclinical infection group were taking immunosuppressive agents, received electrode replacement, or received CIED upgrade and temporary pacing. Patients in the subclinical infection group had a higher PADIT (Prevention of Arrhythmia Device Infection Trial) score. Univariable and multivariable logistic regression analysis found that use of immunosuppressive agents (odds ratio [OR], 6.95 [95% CI, 1.44–33.51]; P=0.02) and electrode replacement or CIED upgrade (OR, 6.73 [95% CI, 2.23–20.38]; P=0.001) were significantly associated with subclinical CIED infection. Meanwhile, compared with the low‐risk group, patients in the intermediate/high‐risk group had a higher risk of subclinical CIED infection (OR, 3.43 [95% CI, 1.58–7.41]; P=0.002). After a median follow‐up time of 36.5 months, the end points between the subclinical infection group and noninfection group were as follows: composite events (58.0% versus 41.8%, P=0.03), rehospitalization (54.0% versus 32.1%, P=0.002), cardiovascular rehospitalization (32.0% versus 13.9%, P=0.001), CIED infection (2.0% versus 0.5%, P=0.32), all‐cause mortality (28.0% versus 21.5%, P=0.30), and cardiovascular mortality (10.0% versus 7.6%, P=0.57).

Conclusions

Subclinical CIED infection was a common phenomenon. The PADIT score had significant value for stratifying patients at high risk of subclinical CIED infection. Subclinical CIED infection was associated with increased risks of composite events, rehospitalization, and cardiovascular rehospitalization.

Microbiological Characteristics and Clinical Features of Cardiac Implantable Electronic Device Infections at a Tertiary Hospital in China

The incidence of cardiac implantable electronic device (CIED) infections is rapidly increasing worldwide. However, the microbiological characteristics and clinical features of symptomatic CIED infections are not well described. The present study included patients with CIED infections in China, and their pocket tissues were collected for clinical microbiological determination. A total of 219 patients with CIED infections were investigated; of these patients, 145 (66.2%) were positive for CIED infection in pocket tissue cultures and 24 (11.0%) were positive in both blood and pocket tissue cultures. Patients with recurrent infections and patients with systemic infections tended to have higher rates of positive cultures from pocket tissue. In addition, patients with lung diseases were more likely to have early CIED infections than late CIED infections, while patients with liver diseases were more susceptible to systemic infections than local infections. Staphylococcus species were the most common cause of CIED infections; coagulase-negative staphylococci was the predominant type (accounting for 45.2% in all cases and 68.3% in culture-positive cases). None of the Staphylococcus isolates were resistant to gentamicin, linezolid or vancomycin. Gram-negative bacilli accounted for 9.1% of all cases and 13.8% of culture-positive cases. Significant differences in the distribution of different pathogens were identified between primary infections and recurrent infections, between local infections and systemic infections, and between early infections and late infections. Our data describe the microbiological characteristics and clinical features of CIED infections, and provide evidence for advisory guidelines on the management of CIED infections in China.

Microbial diagnosis of infection and colonization of cardiac implantable electronic devices by use of sonication

OBJECTIVES

The clinical utility of sonication as an adjunctive diagnostic tool for the microbial diagnosis of cardiac implantable device-associated infections (CIDAIs) was investigated.

METHODS

The implants of 83 subjects were investigated, 15 with a CIDAI and 68 without a clinical infection. Clinical data were analyzed prospectively and sonication fluid cultures (83 patients, 100%) and traditional cultures (31 patients, 37.4%) were performed

RESULTS

Generator pocket infection and device-related endocarditis were found in 13 (86.7%) and four (26.7%) subjects, respectively. The mean numbers of previous technical complications and infections were higher in the infected patients compared to the non-infected patients (8 vs. 1, p<0.001; 2 vs. 0, p<0.031, respectively). The sensitivity and specificity for detecting CIDAI was 73.3% (11/15) and 48.5% (33/68) for sonication fluid culture, and 26.7% (4/15) and 100% (16/16) for traditional culture (p<0.001), respectively. A higher number of organisms were identified by sonication fluid than by tissue culture (58 vs. 4 specimens; p<0.001). The most frequent organisms cultured were Gram-positive cocci (66.1%), mainly coagulase-negative staphylococci (35.5%). Thirty-five (51.5%) non-infected subjects were considered colonized due to the positive identification of organisms exclusively through sonication fluid culture.

CONCLUSIONS

Sonication fluid culture from the removed cardiac implants has the potential to improve the microbiological diagnosis of CIDAIs.