Comparison of Outcome of Possible Versus Definite Infective Endocarditis Involving Prosthetic or Bioprosthetic Heart Valves

The objectives of this study were to describe and compare the clinical characteristics and outcomes of patients with definite and possible infective endocarditis (IE) involving prosthetic heart valve, and to identify prognostic factors for long-term mortality, using data from an unselected cohort of consecutive patients. We studied data from 133 consecutive patients with IE involving prosthetic heart valve seen in an academic institution between 1990 and 2012. Patients were classified according to the modified Duke criteria for IE: patients with possible IE (n = 47, 35%) and patients with definite IE (n = 86, 65%). Overall, 55 patients died over a mean ± SD follow-up of 3.6 ± 4.1 years (median 1.8, interquartile range 4.4 years). Patients with definite IE had a higher risk of death (hazard ratio [HR] 2.21, 95% confidence interval [CI] 1.20 to 4.17 p = 0.01). Independent predictors of long-term mortality were increasing age (HR 1.05, 95% CI 1.02 to 1.08, p = 0.002), Staphylococcus aureus infection (HR 3.40, 95% CI 1.00 to 11.76; p = 0.05), infection with unknown microorganism (HR 12.50, 95% CI 2.97 to 52.63; p = 0.0006), and definite IE (HR 8.70, 95% CI 3.55 to 21.28; p <0.0001), whereas infection on pacemaker or defibrillator (HR 0.30, 95%CI 0.10 to 0.87; p = 0.03) was associated with a better prognosis. Patients with definite IE and those with possible IE who underwent surgery had a nonsignificantly better prognosis than their counterparts with no surgery. In conclusion, patients with definite IE (Duke criteria) on a prosthetic heart valve independently had a worse prognosis than those with possible IE.