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Comparison between early and late prosthetic valve endocarditis: clinical characteristics and outcomes.

BACKGROUND AND AIM OF THE STUDY
Prosthetic valve endocarditis (PVE) is considered a time-related event. The study aim was to compare the clinical characteristics and outcomes of early- and late-onset PVE, and to investigate potential preventive measures for each condition.


METHODS
A total of 47 consecutive patients undergoing surgery for PVE between January 1986 and December 2011 were analyzed retrospectively, and classified as an early-onset group (n = 26; PVE occurring within 12 months after previous surgery) and late-onset group (n = 21; PVE occurring after 12 months).


RESULTS
The prosthetic valve position significantly affected the incidence of endocarditis: 21 cases (80.7%) in the early-onset group had infected aortic prostheses, while 18 (85.7%) in the late-onset group had infected mitral prostheses (p = 0.028). PVE significantly affected bioprosthetic valves in the early-onset group (18 cases, 69.2%) and mechanical valves in the late-onset group (17 cases, 80.9%) (p < 0.01). Staphylococcus spp. infections were predominant in the early-onset group (21 cases, 80.7%), and Streptococcus spp. in the late-onset group (five cases, 23.8%) (p = 0.03). Operative deaths occurred in both the early-onset (n = 6; 23.0%) and late-onset (n = 2; 9.5%) groups (p = 0.11). The long-term mortality in the early-onset and late-onset groups, respectively, was 40.3 +/- 17.7% and 85.1 +/- 7.9% at 10 years, and 40.3 +/- 17.7% and 72.9 +/- 13.1% at 15 years (p 0.047). Freedom from recurrent endocarditis after two years in the early- and late-onset groups, respectively, was 67.8 +/- 10.1% and 88.8 +/- 7.4% (p = 0.048).


CONCLUSION
Clinical characteristics and outcomes differed significantly between early- and late-onset PVE. The clinical outcomes of patients with early PVE tend to be serious, and therefore stringent care should be taken to avoid contamination during the initial surgery and hence to reduce the incidence of the condition.