CardioNerds (Drs. Amit Goyal, Matthew Delfiner, and Tiffany Dong) discuss infective endocarditis with distinguished clinician-educator Dr. Michael Cullen. We dive into the nuances of infective endocarditis, including native valve endocarditis, prosthetic valve endocarditis, and right-sided endocarditis.
Notes were drafted by Dr. Tiffany Dong, and audio editing was performed by student Dr. Adriana Mares.
The physical exam is crucial in the evaluation of infective endocarditis and includes cardiac auscultation and a search for sequelae of endocarditis, such as immunologic and embolic phenomena.
The modified Duke Criteria categorizes the diagnosis of infective endocarditis into four different buckets: definite endocarditis by pathology, definite endocarditis by clinical criteria, possible endocarditis, and rejected.
The diagnosis of endocarditis may involve several different imaging modalities, including transthoracic echocardiogram, transesophageal echocardiogram, 4D CT, and nuclear imaging.
For left-sided endocarditis, indications to operate include endocarditis due to S. aureus or fungi, heart failure, evidence of perivalvular complications, persistent bacteremia, and large vegetations.
The management of endocarditis often involves multiple teams, including cardiology, infectious disease, addiction medicine, neurology, anesthesiology, and cardiothoracic surgery.
Notes
What signs/complications of endocarditis are apparent on physical exam and labs?
A new or worsening cardiac murmur with possible signs of volume overload.
Immunologic phenomena include glomerulonephritis, Roth spots, and Osler nodes.
Positive blood cultures with 2-3 samples collected.
Elevated inflammatory markers.
How does the modified Duke criteria assist in the diagnosis of infective endocarditis?
The modified Duke criteria separate the diagnosis of endocarditis into four categories: definite endocarditis by pathology, definite endocarditis by clinical criteria, possible endocarditis, and rejected endocarditis.
Definitive endocarditis by pathology requires pathologic confirmation of “bugs under the microscope.”
Definitive endocarditis by clinical criteria requires two major criteria, one major and two minor criteria, or all five minor criteria.
Possible endocarditis requires one major and one minor or three minor criteria.
Major criteria:
Positive blood culture for typical organism
Evidence of endocardial involvement (e.g., vegetation on echo)
Minor Criteria
Predisposing clinical factors (e.g., intravenous drug use, known valvulopathy)
Fever
Immunologic phenomena
Vascular phenomena
Blood culture for atypical organism
What is the role of TTE compared to TEE in endocarditis?
TTE and TEE both have their roles in the workup for endocarditis.
TTE can provide a baseline screen and yield a better understanding of ventricular size and function than transesophageal.
The strength of TEE is the ability to visualize smaller vegetations along with perivalvular complications that may be missed on TTE.
If clinical suspicion is high for endocarditis, repeat echocardiography is warranted.
What are other tools to evaluate for endocarditis in prosthetic valves?
TTE and TEE remain important and should be commonly utilized for the diagnosis of endocarditis.
FDG-PET can detect inflammation that could be suggestive of endocarditis. Patients should be at least six weeks after valve implantation; otherwise, FDG PET may detect normal postsurgical inflammation.
Gated 4D CT can also screen for perivalvular involvement and aid with surgical planning, especially in these patients who may undergo redo surgery.
What are the indications for surgery in infective endocarditis?
It is important to separate left-sided and right-sided endocarditis because the indications are different.
For left-sided endocarditis, indications for surgery include persistent bacteremia/fevers despite appropriate antibiotic therapy, S. aureus or fungal endocarditis, heart failure symptoms, perivalvular complications, and vegetations >20mm.
For right-sided endocarditis, indications for surgery include infection with a fungal organism, heart failure due to severe tricuspid regurgitation, vegetations >10mm with embolic phenomenon, persistent bacteremia despite appropriate therapy, and perivalvular involvement.
Often, medical therapy alone for right-sided endocarditis will be sufficient.
What is the role of multidisciplinary teams for endocarditis?
Endocarditis teams can involve cardiology, infectious disease, cardiothoracic surgery, neurology, anesthesiology, and addiction medicine.
Addiction medicine is a very important group, particularly in cases where endocarditis is related to IVDU. It is a class 1 indication to consult addiction medicine to give the patient the best long-term outcome.
Even if surgery is not warranted at initial hospitalization, it may be appropriate to have cardiac surgery weigh in and follow up with the patient in case there arises an indication for surgery.
References
Habib G, Lancellotti P, Antunes MJ, et al. 2015 ESC Guidelines for the management of infective endocarditis: The Task Force for the Management of Infective Endocarditis of the European Society of Cardiology (ESC). Endorsed by: European Association for Cardio-Thoracic Surgery (EACTS), the European Association of Nuclear Medicine (EANM). European heart journal. Nov 21 2015;36(44):3075-3128. doi:10.1093/eurheartj/ehv319 https://academic.oup.com/eurheartj/article/36/44/3075/2293384
Otto CM, Nishimura RA, Bonow RO, et al. 2020 ACC/AHA Guideline for the Management of Patients With Valvular Heart Disease: Executive Summary: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation. Feb 2 2021;143(5):e35-e71. doi:10.1161/cir.0000000000000932 https://www.ahajournals.org/doi/10.1161/CIR.0000000000000923#d1e11386
Baddour LM, Wilson WR, Bayer AS, et al. Infective Endocarditis in Adults: Diagnosis, Antimicrobial Therapy, and Management of Complications: A Scientific Statement for Healthcare Professionals From the American Heart Association. Circulation. Oct 13 2015;132(15):1435-86. doi:10.1161/cir.0000000000000296 https://www.ahajournals.org/doi/pdf/10.1161/CIR.0000000000000296