title: A Retrospective Review: Significance of Vegetation Size in Injection Drug Users with Right-Sided Infective Endocarditis.
abstract: BACKGROUND
  Previously described prognostic markers in right-sided infective endocarditis (RSIE) include vegetation size ≥1cm, fever for more than three weeks, cardiac failure and severe sepsis. This study aimed to evaluate effectiveness of medical therapy for vegetations ≥1cm and explore determinants of outcome in a representative population of intravenous drug users (IDUs) at a metropolitan Australian health service.
  
  
  METHODS
  Retrospective review of consecutive IDUs presenting to our institution with native-valve RSIE (by modified Duke criteria) over seven years (2005-2011). Data recorded included echocardiographic estimation of maximal vegetation diameter (classified as < or ≥1cm). Relationships between vegetation size and specified outcomes of death, septic shock, recurrence and relapse were examined by Chi-squared testing.
  
  
  RESULTS
  Of 49 episodes five (10%) were managed surgically and a further four (8%) were lost to follow-up and excluded from the analysis. Of the remaining 40 evaluable medically treated patients (median age 28, range 20-55), 37 (93%) cultured methicillin-sensitive S. aureus and all had tricuspid valve involvement. Of 24 with vegetations ≥1cm, three died (mortality 13%) compared with one (6%) in 16 medically treated patients with vegetations <1cm (p=0.63). A Pittsburgh (PITT) bacteraemia score of ≥4 at presentation was associated with a mortality of 24% (four of 17 patients died) compared with 0 in 23 patients with PITT scores <4 (p=0.026).
  
  
  CONCLUSIONS
  Medical therapy alone can be effective for RSIE when large vegetations are present. However a high sepsis score at presentation may increase risk of death. Larger studies are required to determine optimal indications for early surgical intervention.
authors.affiliation: Infectious Diseases Department, Western Hospital, Melbourne, Vic., Australia. Electronic address: o.hide@hotmail.com.
authors.forename: Ohide
authors.initials: O
authors.lastname: Otome
authors.affiliation: Infectious Diseases Department, Western Hospital, Melbourne, Vic., Australia.
authors.forename: Stephen
authors.initials: S
authors.lastname: Guy
authors.affiliation: Infectious Diseases Department, Western Hospital, Melbourne, Vic., Australia.
authors.forename: Adrian
authors.initials: A
authors.lastname: Tramontana
authors.affiliation: Infectious Diseases Department, Western Hospital, Melbourne, Vic., Australia.
authors.forename: Garry
authors.initials: G
authors.lastname: Lane
authors.affiliation: Department of Medicine, Western Hospital, Melbourne, Vic., Australia; North West Academic Centre, The University of Melbourne, Western Hospital, Melbourne, Vic., Australia; Walter and Eliza Hall Institute, Melbourne, Vic., Australia.
authors.forename: Harin
authors.initials: H
authors.lastname: Karunajeewa
mesh_terms: D000328:Adult; D000359:Aftercare; D001315:Australia; D004697:Endocarditis, Bacterial / Q000209:etiology / Q000382:microbiology / Q000401:mortality; D005260:Female; D006801:Humans; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus; D008875:Middle Aged; D012189:Retrospective Studies; D013203:Staphylococcal Infections / Q000209:etiology / Q000382:microbiology / Q000401:mortality; D019966:Substance-Related Disorders / Q000150:complications / Q000382:microbiology / Q000401:mortality
keywords: Infective endocarditis; Injection-drug-use; Right-side; Vegetation