From the Guidelines
The new criteria for infective endocarditis are the modified Duke criteria, which include both major and minor criteria for diagnosis. The two major criteria are: 1) positive blood cultures for typical endocarditis organisms from two separate blood cultures, and 2) evidence of endocardial involvement on echocardiography (such as an oscillating intracardiac mass, abscess, or new valvular regurgitation) 1. The minor criteria include:
- Predisposing heart conditions
- Fever above 38°C (100.4°F)
- Vascular phenomena (like arterial emboli or septic pulmonary infarcts)
- Immunologic phenomena (such as glomerulonephritis or Osler's nodes)
- Positive blood cultures not meeting major criteria or serological evidence of infection A definite diagnosis requires either two major criteria, one major plus three minor criteria, or five minor criteria 1. Possible endocarditis is diagnosed with one major plus one minor criterion or three minor criteria. These criteria help standardize the diagnosis of infective endocarditis, which can be challenging due to its variable presentation. Early diagnosis is crucial for prompt antibiotic treatment, which typically involves 4-6 weeks of intravenous antibiotics tailored to the causative organism, sometimes followed by surgical intervention for valve repair or replacement in severe cases 1.
The modified Duke criteria have been validated in several studies, including a study published in 2015, which confirmed the high sensitivity and specificity of the criteria for diagnosing infective endocarditis 1. Another study published in 2005 also supported the use of the modified Duke criteria, highlighting the importance of echocardiography in diagnosing infective endocarditis 1.
In clinical practice, the modified Duke criteria should be used to guide the diagnosis and management of infective endocarditis, taking into account the patient's individual risk factors and clinical presentation 1. The criteria should be applied in a flexible and nuanced manner, considering the potential for false negatives and false positives, and the need for prompt and effective treatment to prevent complications and improve outcomes 1.
Overall, the modified Duke criteria provide a standardized and evidence-based approach to diagnosing infective endocarditis, and should be used in conjunction with clinical judgment and expertise to guide patient management and improve outcomes 1.
From the Research
New Criteria for Infective Endocarditis
The new criteria for infective endocarditis, as defined by the 2023 Duke-International Society of Cardiovascular Infectious Diseases Diagnostic Criteria 2, include:
- Microbiology criteria
- Positron emission tomography-computed tomography
- Cardiac implanted electronic devices These criteria aim to improve the diagnosis and classification of patients with suspected endocarditis.
Comparison with Modified Duke Criteria
The 2023 Duke-ISCVID criteria were compared with the modified Duke criteria in a study of 4050 episodes of bacteremia 2. The results showed that:
- 13 episodes were reclassified from possible to definite IE
- 475 episodes were reclassified from rejected to possible IE
- The sensitivity of the Duke-ISCVID criteria was 80%
Diagnostic Classification
The diagnostic classification of infective endocarditis using the new criteria includes:
- Definite IE
- Possible IE
- Rejected IE The new criteria aim to minimize the possible IE group while keeping or improving sensitivity.
Clinical Management
The decision to treat for IE was used as a reference standard to evaluate the sensitivity of the Duke-ISCVID criteria 2. The results showed that:
- 79 episodes that were treated as IE were classified as possible IE using the modified Duke criteria
- 11 of these episodes were reclassified to definite IE using the Duke-ISCVID criteria
- None of the 475 episodes reclassified to possible IE were treated as IE
Previous Criteria
Previous studies have defined the criteria for infective endocarditis, including the Duke Endocarditis Service criteria 3, which defined two "major criteria" and six "minor criteria" for the diagnosis of infective endocarditis. These criteria have been widely used and have formed the basis for subsequent revisions and updates.