Individual value of each of the Duke criteria for the diagnosis of infective endocarditis

Assesment of the Duke criteria for the diagnosis of infective endocarditis after twenty-years. An analysis of 241 cases

BACKGROUND AND AIMS

In the absence of classical features (fever, cardiac murmur, and peripheral vascular stigmata) the diagnosis of infective endocarditis (IE) may be difficult. Current clinical guidelines for the diagnosis and management of IE recommend the use of modified Duke criteria. Correct and prompt diagnosis of IE is crucial for the treatment and outcome of the patients. The aim of this study was to evaluate the presence and the individual value of each criterion of the modified Duke criteria in our patients with infective endocarditis.

METHODS

We performed a prospective observational study between January 2008 - June 2014, in which we enrolled consecutive adult patients admitted for suspicion of IE to the Hospital of Infectious Diseases and at the Heart Institute . We used and extensive database in order to collect demographic data, laboratory and echocardiography results, evolution and outcome of the patients. Using the modified Duke criteria we identified 3 categories of IE: definite, possible and rejected. In order to evaluate the importance of each criterion in the diagnosis of IE we tested two hypotheses. First, we excluded each criterion from the final diagnosis and we counted how many cases felt into a lower category. Second, after adding each major and minor criterion, we tested how many cases would have been classifiable as definite IE.

RESULTS

The study included 241 adult patients with a mean age 58.16 years and sex ratio male/female 1.94. According to the modified Duke criteria 137 patients had definite IE, 79 patients had possible IE and 25 cases had rejected IE We had blood cultures positive IE in 109 cases and blood culture negative IE (BCNE) in 132 (71.21%) cases. Antibiotic treatment prior to blood culture was recorded in 152 (63.07%) patients. In the absence of the echocardiography major criterion, 43% of cases would become possible. After extraction of major microbiological criterion, only one third of definite cases would become possible. Minor criteria such as fever and predisposition contributed to the diagnosis only in 10% of cases. In the presence of vascular or immunological phenomena, or in the presence of minor microbiological criterion, half of the possible IE cases could become possible.

CONCLUSION

Twenty-years after their launch, the Duke criteria for the diagnosis of IE continue to be important tools. Low index of suspicion of IE and inappropriate use of antibiotics may have a great negative impact on the diagnosis of IE. Nowadays, the scarcity of classical Osler manifestations - bacteremia, fever and peripheral stigmata - makes the diagnosis of IE a challenge.

Infective endocarditis with negative blood cultures

Culture-negative endocarditis is important as it has a relatively poor prognosis. The principal reason for negative cultures is prior antibiotic therapy although fastidious organisms such as Bartonella spp. and Coxiella burnetii are also important. PCR may offer significant advantages in diagnosis but tests require standardisation. Modification of current diagnostic criteria is required. Empirical cover of MRSA needs to be considered.

German guidelines for the diagnosis and management of infective endocarditis

This Gudelines are the translation of the German Guidelines for the Diagnosis and Management of Infective Endocarditis, which were prepared by the Working Group on Infective Endocarditis of the Paul-Ehrlich-Society and the German Society for Cardiology, Heart, and Circulatory Research in cooperation with the Deutsche Gesellschaft für Thorax-, Herz und Gefässchirurgie (DGTHG; German Society for Thorax-, Cardiac-, and Vascular Surgery), the Deutsche Gesellschaft für Infektiologie (DGI; German Society for Infectious Diseases), the Deutsche Gesellschaft für Internistische Intensivmedizin und Notfallmedizin (DGIIN; German Society for Internal Intensive Care Medicin and Emergency Medicine), the Deutsche Gesellschaft für Hygiene und Mikrobiologie (DGHM; German Society for Hygiene and Microbiology) and the Deutsche Gesellschaft für Innere Medizin (DGIM; German Society for Internal Medicine) (Naber CK et al. [S2 Guideline for diagnosis and therapy of infectious endocarditis] Z Kardiol. 2004;93:1005-21). The Guidelines provide recommendations for the diagnosis and management of infective endocarditis.

Are all echocardiographic findings equally predictive for diagnosis in prosthetic endocarditis?

OBJECTIVE

The purpose of this study was to analyze the predictive value of different anatomic echocardiographic findings for diagnosis of prosthetic endocarditis.

BACKGROUND

Prognosis in endocarditis has improved in recent years after the wide acceptance of new clinical diagnostic criteria. One of the most important issues in clinical diagnosis is to use echocardiography for identification of endocardial involvement, but prosthetic material impairs echo quality.

METHODS

In all, 49 patients with 58 episodes of suggested prosthetic endocarditis were prospectively studied using transthoracic and transesophageal echocardiography. The patients were divided into two groups: group A, patients with 34 episodes of definite endocarditis according to Durack's criteria; and group B, patients with 24 episodes who were eventually classified as not having endocarditis, either by surgical exploration or by a mean of 32.6 months (range: 8-38 months) of follow-up.

RESULTS

In group A, valve dehiscence was observed in 4 episodes of suggested endocarditis, pseudoaneurysms in 3, fistulae in 2, and moderate to severe perivalvular regurgitation in 15. No patient in group B had these abnormalities (P <.001). Vegetations were present in 17 episodes in group A (50%) versus 1 in group B (9%; P <.001); perivalvular abscesses were seen in 19 episodes in group A (56%) versus 1 in group B (P <.001). Mild perivalvular regurgitation was observed in only 1 episode for group A (3%) and in 14 episodes for group B (58%; P <.01). The presence of any of the above echocardiographic finding, when used in combination with the exclusion of mild perivalvular regurgitation, had a positive and negative predictive value for diagnosing endocarditis of 94% and 96%, respectively. Isolated mild perivalvular regurgitation had a poor positive predictive value (6%).

CONCLUSION

Isolated mild perivalvular regurgitation should not be used as diagnostic criteria in patients with suggested prosthetic valve endocarditis.

A clinical study of culture-negative endocarditis

Culture-negative infective endocarditis (CNE) is a diagnostic problem in spite of improved echocardiographic and blood culturing techniques. We conducted the present study to estimate the proportion of CNE in patients with infective endocarditis, to investigate data regarding risk factors, and to evaluate the Duke and the modified Beth Israel criteria in patients with CNE. We evaluated 820 consecutive suspected episodes of infective endocarditis in adults at the Departments of Infectious Diseases in Göteborg and Borås, Sweden (1984-1996). All patients were diagnosed and treated according to a protocol; 487 episodes were identified as infective endocarditis. Episodes with absence of bacterial growth at blood culture were defined as CNE and were classified with the Duke and the modified Beth Israel criteria. We identified 116 CNE episodes (median age, 67 yr). Mortality was 7%, and in 15%, cardiac surgery was performed. The Duke criteria classified 20 definite, 80 possible, and 16 reject episodes. The modified Beth Israel criteria distinguished 13 definite, 15 probable, 27 possible, and 61 reject episodes. The proportion of CNE among patients with infective endocarditis varied from 19% to 27% at the 2 departments. Antibiotic treatment preceded blood culture in 45% of the CNE episodes. About 20% in a Scandinavian population of infective endocarditis patients have CNE. Antibiotic pretreatment explains less than 50% of all CNE episodes. The Duke criteria are more sensitive but less specific than the modified Beth Israel criteria in classifying patients with CNE.

Diagnostic methods. Current best practices and guidelines for isolation of bacteria and fungi in infective endocarditis

As the etiological character of IE changes, the microbiological tools used to confirm the diagnosis have also evolved. Here the authors have reviewed the current methods for optimal laboratory diagnosis of bacterial and fungal endocarditis using traditional growth-based technologies and offered good practice guidelines and recommendations. Newer techniques will be required to improve sensitivity of detection for known organisms and to identify emerging or as-yet unknown pathogens (see article by Lepidi et al in this issue).

Diagnostic methods current best practices and guidelines for isolation of bacteria and fungi in infective endocarditis

This article addresses the clinical need for accurate detection of bacteria and fungi that may cause infective endocarditis (IE). The pathophysiology of bacteremia during endocarditis is reviewed to provide an understanding of how current diagnostic methods may be used to determine the etiologic diagnosis. The critical contribution of microbiologic findings to the current clinical diagnostic criteria is emphasized. Finally, "best practices" recommendations are presented to optimize the likelihood of reaching a correct etiologic diagnosis while minimizing the number of "culture-negative" cases.