Infective Endocarditis Diagnosis and Management

Echocardiographic Findings and Imaging Recommendations

The European Society of Cardiology and American Heart Association recommend considering echocardiographic findings such as vegetations, abscesses, pseudoaneurysms, valvular perforation/aneurysm, new partial dehiscence of prosthetic valve, and new valvular regurgitation as evidence of endocardial involvement, with transthoracic echocardiography (TTE) as the first-line imaging modality and transesophageal echocardiography (TEE) as the second-line imaging modality 1, 2, 3
TTE should be performed within 12 hours of initial evaluation, with a sensitivity of 50-70% and specificity >90%, while TEE has a sensitivity >90% and specificity >95% and is indicated when there is high clinical suspicion with negative/inconclusive TTE, prosthetic valves, suspected complications, or poor quality TTE images 2

Definite IE diagnosis requires 2 major criteria, or 1 major criterion and 3 minor criteria, or 5 minor criteria, as recommended by the European Society of Cardiology 3, 1, 2, 4
Major criteria for IE diagnosis include:
Minor criteria for IE diagnosis include:

The European Society of Cardiology suggests considering prior antibiotic therapy, fastidious organisms, serological testing, and molecular techniques in cases of culture-negative endocarditis, which accounts for 2.5-31% of cases 1
Examination of resected valve tissue remains the gold standard for diagnosis, and can guide antimicrobial treatment if the causative agent is identified, as stated by the European Society of Cardiology 1

Patients with IE should receive appropriate antibiotic therapy targeting the causative organism and be evaluated for surgical intervention, especially in cases with valve abscess, as recommended by the American Heart Association and European Society of Cardiology 1, 3, 4
High-risk patients requiring urgent intervention include those with heart failure, periannular complications, S. aureus infection, and prosthetic valve endocarditis, as recommended by the European Society of Cardiology, with mortality risk reaching 79% when three risk factors are present 3
Early consultation with cardiac surgery is recommended for heart failure due to valve dysfunction, uncontrolled infection, prevention of embolic events, and prosthetic valve endocarditis with complications, and high-risk patients should be managed by a multidisciplinary team including cardiologists, cardiac surgeons, infectious disease specialists, and microbiologists 3
Prosthetic valve endocarditis has higher mortality and complication rates, is more likely to require surgical intervention, and has a different microbial profile (S. epidermidis common in early PVE), as noted by the American College of Cardiology 5
Repeat echocardiography is recommended 7-10 days after initial examination if clinical suspicion remains high, or when new complications are suspected, and TTE at completion of antibiotic therapy, as recommended by the American Heart Association and European Society of Cardiology 1, 2