Risk factors for early onset prosthetic valve endocarditis: a case-control study

Abstract

Background: Early onset prosthetic valve endocarditis (EO-PVE) is an infrequent complication of cardiac valve surgery. It is considered a healthcare-associated infection due to contamination of the prosthesis during the implant or in the early postoperative period.

Aim: To evaluate which factors may be related to the acquisition of EO-PVE.

Methods: A nested case-control study was conducted from 2006 to 2016. Cases were patients who had definite prosthetic endocarditis by the modified Duke criteria up to 12 months of heart valve replacement. Cases and controls were matched by age, gender, date and type of surgery.

Findings: There were 26 cases and 78 controls, in 2496 valve surgeries. The median incidence of EO-PVE was 1.1%. Risk factors identified during surgery were: use of ≥2 cryoprecipitate units (odds ratio (OR): 5.95; 95% confidence interval (CI): 1.31-27.0) and ≥2 plasma units (OR: 2.73; 95% CI: 1.0-7.5). In the postoperative period, associated factors were bloodstream infection (OR: 14.00; CI: 1.49-131.77), pneumonia (4.38; 1.21-15.84), any infection (4.46; 1.63-12.21), central line for ≥2 weeks (5.33; 2.06-13.78), presence of dialysis catheter (3.22; 1.15-9.03), and new open chest surgery (3.89; 1.28-11.78). Mortality at 12 months was 34.6% in cases and 6.4% in controls (OR: 7.73; CI: 2.3-26.06).

Conclusion: Cases had more infections, invasive procedures and surgical re-interventions in the early postoperative period, which favoured contamination of the newly implanted prosthesis. A preventive approach, with reinforcement of infection control practices, may curb the incidence of this condition.

Keywords: Cardiac surgery; Early onset endocarditis; Nosocomial infection; Prosthetic endocarditis; Prosthetic valve; Risk factors.