Cardiovascular outcomes after Staphylococcus aureus bacteraemia in patients with cardiac implantable electronic devices without prior infective endocarditis

Background In patients with cardiac implantable electronic devices (CIED), device removal is advised in cases of S. aureus infective endocarditis (IE) or CIED infection. In contrast, patients with CIED and S. aureus bacteraemia (SAB), without signs of IE or CIED infection, constitute a clinical challenge in terms of diagnostics and management. Purpose We aimed to estimate clinical outcomes in patients with CIED and SAB without signs of IE or CIED infection who survived SAB hospitalization. Methods Using the Danish Pacemaker and ICD register and the National Danish S. aureus bacteraemia database, we identified adult Danish patients with CIED and first-time SAB without IE between 2000-2023. The primary endpoint was a composite of all-cause death, SAB reinfection and IE hospitalization within 180 days. Index was defined as date of hospital discharge from index SAB. CIED removal was assessed at hospital discharge. To differentiate SAB episodes, a 14-day blanking period was introduced from date of discharge. Results We identified 1,196 CIED carriers (median age 78 years [IQR 70-84], 75.4% males) who survived hospitalization for first-time SAB without a diagnosis of IE or CIED infection. Within 180 days, 415 patients reached the primary endpoint, with a cumulative incidence (cum.inc.) of 35.1% [95% CI: 32.4-37.8] (Figure). When evaluating the individual components of the primary endpoint, the main driver was all-cause death (n=374) with a cum.inc. of 31.6% [29.0-34.3%]. IE hospitalization and SAB reinfection occurred in 27 (cum.inc. 2.3% [1.4-3.1]) and 56 (cum.inc.4.8% [3.5-6.0]) patients, respectively. Sixty-three patients (5.3%) underwent CIED removal a median of 4 days [IQR 2-12] from SAB diagnosis. Patients with retained CIEDs (n=1,133) were significantly older (median age 78 vs. 69 years, p< 0.0001) and had a higher prevalence of COPD and chronic renal disease compared to those undergoing CIED removal. Crude 180-days cum. inc. of all-cause death was lower among patients undergoing CIED removal compared to those with retained CIEDs (9.6% vs. 32.9%, p<0.001). However, we observed no difference between the groups with respect to IE hospitalization (Gray’s test p=0.61) or SAB reinfection (p=0.23). Within 90 days of CIED removal, 40 (63%) patients had a new CIED implanted a median of 19 days [IQR 10.5-32.5] from initial removal. Conclusions Patients with CIED and SAB, who survived SAB hospitalization without diagnosed IE or CIED infection had a high 180-day risk of a composite endpoint of all-cause death, SAB reinfection or IE, with death being the main driver. At 180-days, all-cause death was significantly lower among patients undergoing CIED removal compared to those with retained devices. SAB reinfection and IE were similar regardless of CIED removal, however, the results lack statistical power to draw definite conclusions, highlighting the need for larger population-based studies.