Background and aim of the study: Higher morbidity and mortality have been attributed to patients suffering endocarditis but with negative blood cultures. The study aim was to determine whether, in the present era of routine echocardiography, patients with negative-culture endocarditis had a worse short- and long-term outcome, and whether outcomes in patients with true negative and aborted positive blood cultures were different.
Methods: When endocarditis was clinically suspected, an early (<24 h) echocardiographic examination was performed in all patients, regardless of blood culture results. In total, 151 patients diagnosed with infective endocarditis (IE) comprised the study group. Among these patients, 40 (26%) had negative blood cultures, and 28 of this subgroup (70%) had received previous antibiotic therapy. Short- and long-term features and prognosis were compared between both groups. The combined

main end-point was death or need for surgical repair.
Results: Similar anatomic and clinical characteristics were present among those patients with positive and negative cultures. In addition, mortality and need for surgery with regard to short- and long-term follow up of both groups was similar. There were no significant differences between patients with true- or aborted-negative cultures in terms of short- and long-term prognosis.
Conclusion: No differences in short- and long-term prognosis were seen among patients with IE and positive versus negative blood cultures. The prognosis was also similar between those with true negative culture versus aborted negative cultures. Early echocardiography in patients with clinically suspected IE may have changed the outcome in patients with negative cultures.
The Journal of Heart Valve Disease 2004;13:997-1004