Prevalence of bloodstream infection with different microorganisms in patients with cardiac implantable electronic devices - a Danish nationwide cohort study

Background

There is a paucity of real-life data regarding the risk of bloodstream infection (BSI) with different microorganisms and subsequent outcomes in patients with a cardiac implantable electronic device (CIED).

Purpose

To estimate the prevalence of microorganism-specific BSI in patients with CIED. Secondly, to estimate 30 and 180-day rates of infective endocarditis (IE) hospitalisation, and all-cause mortality after BSI.

Methods

We identified patients with a CIED (2010-2023) from the Danish Pacemaker and ICD Register. The primary endpoint of BSI was identified from the Danish Microbiology Database and defined as one or more positive blood cultures after CIED implantation. Microorganisms were identified at species level if available, alternatively at genus or group level. In patients with BSI, secondary outcomes of IE hospitalisation and all-cause mortality within 30 and 180 days from BSI were reported. IE hospitalisations were identified via diagnosis codes in the Danish National Patient Register, mortality from the Danish Civil Registration System.

Results

The study population comprised 98,211 patients (63% males, median age 75 years [IQR: 67, 82]) with CIED [PM n=72,989 (74.3%), ICD n=15,745 (16%), CRT-P n=3,875 (3.9%), CRT-D n=4,930 (5%), leadless pacemaker n=672 (0.7%)]. At inclusion, 42,642 (43.4%) patients had ischaemic heart disease, 31,501 (32.1%) heart failure, 11,032 (11.2%) cancer, 18,277 (18.6%) diabetes, 24,957 (25.4%) had undergone surgery within the last year. A prior diagnosis with BSI or IE was observed in 4,686 (4.8%) and 1,317 (1.3%) patients, respectively.

In the study period, BSI was identified in 12,268 (12.5%) patients, 1,351 (11%) with polymicrobial BSI. We identified more than 250 different species. The most frequent microorganisms were Coagulase-Negative Staphylococci (CoNS), Escherichia coli (E.coli), Staphylococcus aureus (S.aureus) and Streptococcus spp. (Fig. 1).

A diagnosis of IE hospitalisation was registered in 1,451 (11.8%) patients within 30 days from BSI; and in 1,470 (12%) patients within 180 days. All-cause mortality occurred in 3,315 (27%) and 5,341 (43.5%) patients within 30 and 180 days of BSI, respectively (Fig. 2). Among patients hospitalised for IE within 180 days from BSI, S.aureus n=549 (31%), Enterococcus faecalis n=288 (16%) and Staphylococcus epidermidis (S.epidermidis) n=133 (8%) were the predominant species. The most frequent species in patients who died within 180 days from BSI were E.coli n=1113 (17%), S.aureus n=1019 (16%) and S.epidermidis n=434 (7%).

Conclusion

We identified BSI in every eighth CIED patient, caused primarily by CoNS, E.coli, S.aureus and Streptococcus spp. IE hospitalisation and all-cause mortality were observed in 12% and 43.5% of patients within 180 days of BSI, respectively. Our results underscore the diversity of microorganisms involved in BSI, and the need of careful evaluation of BSI in this high-risk patient group.Fig. 1.Prevalence of microorganismsFig. 2.Endpoints: BSI, IE, mortality