What is the clinical significance of the Denova score?

The DENOVA Score: A Validated Tool for Identifying Patients with Enterococcus faecalis Bacteremia Who Don't Need Echocardiography

The DENOVA score is a highly accurate clinical prediction tool that identifies patients with monomicrobial Enterococcus faecalis bacteremia who do not require transesophageal echocardiography (TEE) to rule out infective endocarditis, with 100% sensitivity and 83-85% specificity when using a cutoff of ≥3 points. 1

Components of the DENOVA Score

The DENOVA score consists of 6 variables:

Variable	Points
Duration of symptoms ≥7 days	1
Embolization	1
Number of positive blood cultures (3/3 or majority if >3)	1
Origin of bacteremia unknown	1
Valve disease (pre-existing)	1
Auscultation of heart murmur	1

Clinical Significance and Application

The DENOVA score addresses a critical clinical challenge: determining which patients with E. faecalis bacteremia require TEE to rule out infective endocarditis (IE). This is important because:

1. High-Risk Identification: The score effectively identifies patients at high risk for IE who need TEE evaluation
2. Resource Optimization: Helps avoid unnecessary TEE procedures in low-risk patients
3. Clinical Decision Support: Provides an objective, validated framework for clinical decision-making

Performance Metrics

• Sensitivity: 100% (identifies all cases of IE)
• Specificity: 83-85% (correctly identifies most patients without IE)
• Cutoff Point: Score ≥3 indicates need for TEE
• Score <3: Very low risk for IE; TEE can be safely avoided 1

Comparison to Other Scoring Systems

The DENOVA score is an improvement over the previous NOVA score (Number of positive cultures, Origin unknown, Valve disease, Auscultation of murmur):

• DENOVA has superior specificity (83-85%) compared to NOVA (29-35%) 1, 2
• Both scores maintain excellent sensitivity (100%) for detecting IE
• The addition of Duration of symptoms and Embolization significantly improves risk stratification

Clinical Implementation

When managing a patient with E. faecalis bacteremia:

1. Calculate the DENOVA score based on the 6 variables
2. For scores ≥3: Perform TEE to evaluate for IE
3. For scores <3: TEE can be safely avoided (virtually no risk of missing IE)

Additional Considerations

• Recent research evaluated adding time to positive blood cultures (TTP ≤8 hours) to the DENOVA score but found it did not improve diagnostic accuracy 3
• The DENOVA scoring system has also shown promise when applied to other gram-positive bacteremias, such as Aerococcus species, with similar performance characteristics (100% sensitivity, 89% specificity) 4
• In a validation study across multiple gram-positive bacteremias, DENOVA maintained excellent negative predictive values (98-100%), confirming its utility as a screening tool 2

Pitfalls and Limitations

• The score was specifically validated for monomicrobial E. faecalis bacteremia and may not perform as well in polymicrobial infections
• While the score has excellent sensitivity (100%), there is still a 15-17% false positive rate, meaning some patients without IE will undergo unnecessary TEE
• Clinical judgment should complement the score, particularly in patients with unusual presentations or risk factors not captured by the scoring system

The DENOVA score represents an important advance in the management of E. faecalis bacteremia by providing a reliable method to identify patients who can safely avoid invasive TEE procedures while ensuring all cases of IE are appropriately identified and treated.