3.) Preoperative infection analysis
Of particular interest in the patient analysis was the preoperative infection status. While none of the patient cohorts showed an elevated body temperature under initiated antibiotic therapy, statistically significant differences were detected in the frequency of collected blood cultures and positive pathogen detections. In advance, the most common blood samples (92.9%) were taken in the EL group. In the SR cohort, this measure was carried out in 71.9%, while it was only performed in the SI group in 35.6% of cases. Pathogens were most commonly detected in the EL group (78.2%). Consistently, gram-positive, coagulase-positive cocci (66.7%/40.9%/50%) were predominantly found in all groups (SR/EL/SI), followed by gram-positive, coagulase-negative subspecies (26.7%/40.9%/38.9%). Gram-positive lactobacilli (11.1%/18.2%/11.1%) and gram-negative proteobacteria (2.2%/0%/11.1%) were also frequently detected in all groups, with slightly higher frequencies in the SI group than in the other groups. Multiple pathogens were seen in all groups, with the highest frequency (11.1%) in the SI group. Finally, blood analyses showed the highest inflammatory parameters in the EL cohort (leukocytes: 11.2 Ts/µl, CRP: 6.3 mg/dl, PCT: 3.2 ng/dl), while the SI group showed the lowest signs of inflammation. Echocardiography was able to detect intracardiac lead vegetations most frequently in the EL group (60.7%).
Furthermore, different primary sources of infection were identified in the groups. Isolated pocket infections were significantly more frequent in patients of the SI group (74%), while bloodstream infections represented the dominant etiology in the other two groups (EL: 60.7%, SI: 41.6%) (Table 1).