Diagnostic Criteria and Management of Infective Endocarditis in Elderly Patients

Introduction to Diagnostic Criteria

The European Society of Cardiology recommends using the Modified Duke Criteria as the primary diagnostic framework for infective endocarditis (IE) in elderly patients, with a high index of suspicion due to frequently absent classic clinical signs 1, 2

Non-specific symptoms such as digestive complaints, urinary symptoms, anemia, and cognitive changes are more frequent than classic peripheral stigmata in elderly patients 2
A low threshold for investigation should be maintained in elderly patients with unexplained fever, new heart murmur, or sepsis of unknown origin, even when classic signs are absent 1, 2

The American Heart Association suggests that typical microorganisms from 2 separate blood cultures, such as Viridans streptococci, S. gallolyticus, HACEK group, S. aureus, or community-acquired enterococci, are considered major criteria for IE diagnosis 3, 4
Echocardiographic findings, including vegetation, abscess, pseudoaneurysm, intracardiac valvular perforation, new partial dehiscence of prosthetic valve, or new valvular regurgitation, are also major criteria 3, 4
Paravalvular lesions detected by cardiac CT and abnormal activity around prosthetic valve site on ¹⁸F-FDG PET/CT are considered major criteria as well 3, 5

Definite IE is diagnosed when 2 major criteria, or 1 major + 3 minor criteria, or 5 minor criteria are met 3, 5
Possible IE is diagnosed when 1 major + 1 minor criterion, or 3 minor criteria are met 3, 5

The American College of Cardiology recommends performing transthoracic echocardiography (TTE) first in all suspected cases as initial imaging modality 1, 6, 7
Transesophageal echocardiography (TEE) should be performed immediately when TTE is nondiagnostic and clinical suspicion remains high, or when prosthetic valve is present, or when intracardiac device leads are present 1, 6, 7, 8, 9

At least 3 sets of blood cultures should be obtained from separate venipuncture sites before initiating antibiotics 6, 7
Blood cultures are positive in 90% of IE cases when properly obtained 8

Early involvement of a multidisciplinary "Endocarditis Team" including cardiologist, infectious disease specialist, cardiac surgeon, and microbiologist is highly recommended 1, 2
Complicated IE cases should be referred to reference centers with immediate surgical facilities 2