Infective endocarditis

‍Diagnosis 

The modified Duke criteria can be used to help diagnose IE.

These have an overall sensitivity of 80%, but this is significantly lower in cases of prosthetic valve endocarditis or implantable electronic device infections. 

Major criteria

• Positive blood culture for Infective Endocarditis
• Evidence of endocardial involvement
• Positive echocardiogram for IE defined as :

            - oscillating intracardiac mass on valve or supporting structures, in the path of regurgitant jets, or on implanted material in the absence of an alternative                 anatomic  explanation, or

            - abscess, or

            - new partial dehiscence of prosthetic valve

• New valvular regurgitation (worsening or changing of preexisting murmur not sufficient)
  

Minor criteria

• Predisposition: predisposing heart condition or intravenous drug use
• Fever: T> 38.0° C (100.4° F)
• Vascular phenomena: major arterial emboli, septic pulmonary infarcts, mycotic aneurysm, intracranial hemorrhage, conjunctival hemorrhages, and Janeway lesions
• Immunologic phenomena: glomerulonephritis, Osler nodes, Roth spots, and rheumatoid factor
• Microbiological evidence: positive blood culture but does not meet a major criterion as noted below¹ or serological evidence of active infection with organism consistent with IE
• Echocardiographic findings: consistent with IE but do not meet a major criterion as noted above

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ECHOCARDIOGRAPHY

Echocardiography is central to the diagnosis and management of patients with IE.

Echocardiographic findings are part of the major and minor criteria for diagnosis of infectious endocarditis.

Echocardiography is helpful in:

(1) finding vegetation and determining size

(2) diagnosing complications -> paravalvular abscess, fistula, etc.

(3) examining underlying morphology

(4) assess severity of valve function (regurgitation)

(5) cardiac function

(6) imaging of other heart valves

For most patients with suspected IE, an initial TTE is usually recommended.

When the TTE is nondiagnostic or if there is high clinical suspicion for IE, a TEE is recommended.

TEE is recommended as the initial test for individuals with suspected IE involving a prosthetic heart valve in any location.

Repeat TTE/TEE may be necessary in 5-7 days if IE is suspected and not identified by initial examination.

For those with a vegetation, a TEE is often recommended to evaluate the extent of infection and potential of abscess.

Image 1 Diagnostic approach in IE

Habib G, Lancellotti P, Antunes MJ, et al. ESC Scientific Document Group. 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). Eur Heart J. 2015 Nov 21;36(44):3075-3128. doi: 10.1093/eurheartj/ehv319. Epub 2015 Aug 29. PMID: 26320109.

Vegetation   

Valvular vegetation is defined as "a discrete mass of echogenic material adherent at some point to a leaflet surface and distinct in character from the remainder of the leaflet" based upon the following characteristics:

• Texture – Gray scale and reflectance of myocardium
• Location – Upstream side of the valve in the path of the jet or on prosthetic material
• Characteristic motion – Chaotic and orbiting; independent of valve motion
• Shape – Lobulated and amorphous
• Accompanying abnormalities – Abscess and pseudoaneurysm, fistulae, prosthetic dehiscence, paravalvular leak, significant preexisting or new regurgitation

Image 2 Echo criteria defining a vegetation

Technical tips:

• Assess all valves in zoom mode
• Use highest possible frequency
• Place focal zone at level of valves
• Slow angulation and tilting through the valves from all possigble views to image all aspects of these 3D structures

Some vegetations persist after bacterial cure has been achieved and remain stable in size for many years.

However, chronic lesions are more echogenic than acute vegetations.

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False diagnosis of IE may occur, and insome instances it may bedifficult to differentiate vegetations from:

- Thrombi

- Lambl’s excrescences

- valve fibroelastoma

- degenerative or myxomatousvalve disease

- systemic lupus(Libman–Sacks) lesions

- primary antiphospholipidsyndrome

- rheumatoid lesions

- marantic vegetations

Complications

In addition to its role in diagnosing endocarditis, echocardiography is important for recognizing the intracardiac complications associated with endocarditis.

Image 3 Complications of IE

Image 4 Echocardiographic complications of IE

Adapted from: Habib G, Lancellotti P, Antunes MJ, et al. ESC Scientific Document Group. 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). Eur Heart J. 2015 Nov 21;36(44):3075-3128. doi: 10.1093/eurheartj/ehv319. Epub 2015 Aug 29. PMID: 26320109.

1) Native valve endocarditis

Video 1a Native valve endocarditis with prominent mobile vegetation 13x6x5 mm on a non-coronary cusp of Aortic valve - TEE

Video 2 Large vegetation 22 mm on a right coronary cusp of aortic valve - TEE

Video 3a Mitral valve endocarditis - two large vegetations on a posterior leaflet visible  already on TTE

Image 3b Size of the first vegetation 10x10 mm

Image 3c Second mobile vegetation sizing 19x5 mm

Video 3d Two large mobile vegetations on a posterior mitral valve leaflet seen on TEE

Video 3e Mild to moderate mitral regurgitation caused by vegetations on mitral valve - TEE

Video 4a Perforation of non-coronary cusp in a patient with native valve aortic endocarditis - TEE

Video 4b Severe aortic insufficiency related to destruction of NCC - TEE

Video 4c Severe aortic insufficiency in the same patient in a different view on TTE

Video 5a Perforation of non-coronary cusp in another patient with native aortic valve endocarditis - TEE

Video 5b Perforation of a non-coronary cusp associated with severe aortic regurgitation - TEE

Video 6a Abscess of a non-coronary cusp that led to cusp perforation - TEE

Video 6b Short axis view of a NCC cusp perforation - TEE

Video 7a Deep prolapse (6 mm) of a LCC as a complication of Native aortic valve endocarditis - TEE

Video 7b Prolapse of a LCC associated with severe aortic regurgitation - TEE

Video 8 Fistula between Ao anulus by the right Valsalva sinus and right ventricle caused by perforated abscess (6´ clock) - TEE

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Prosthetic valve endocarditis

Video 9 Infective endocarditis of aortic bioprosthesis - large mobile vegetations clearly visible on originally located right coronary cusp, infection spreads to Ao-Mi continuity (bright inflammed tisue on the side of aortic anulus towards left atrium) - TEE

Video 10 IE of aortic bioprosthesis with an abscess (1´clock), note thickened cusps of bioprosthesis - TEE

Video 11a Perivalvular abscess (12´clock) by the aortic bioprosthesis, note thickened cusps of prosthesis with adjacent vegetations - TEE

Image 11b Size of the perivalvular asbcess - TEE

Video 12a Aortic bioprosthesis with pulsating pseudoaneurysm as a complication of IE (11-12´clock) - TEE

Video 12b Focus na periaortic PSA - TEE

Image 12c Size of PSA - TEE

Video 13a Another patient with pulsating PSA as a complication of IE of aortic bioprosthesis (12´clock) - TEE

Video 13b Cross-sectional view of the PSA in the same patient (12´clock) - TEE

Video 14a Emptied PSA as a complication of IE of mechanical aortic prosthesis (12´clock) - TEE

Video 14b Emptied PSA with partial dehiscence of the prosthesis by the LCC with moderate para-prosthetic regurgitation -TEE

Video 15a Abscess of the periaortic area in a patient with Ao bioprosthesis IE (thickened tissue with multiple holes inside at 10-11´clock) -TEE

Video 15b Fistula between NCC and RCC to right atrium as a complication of IE in the same patient - TEE

Video 15c Colour flow Doppler confirming L-R shunt from Aortic valve to RA - TEE

Video 16a Another patient with fistula as a complication of Ao bioprosthesis IE - observe the possible communication between periaortic area and left atrium (10-11´clock) - TEE

Video 16b Confirmed shunt between periaortic PSA and LA towards mitral valve - TEE

Video 17a Flail of one of the leaflets of mitral bioprosthesis due to IE, also note the thickened leaflets - TEE

Video 17b Resultant severe mitral regurgitation in the same patient -TEE

Video 18a Mitral valve mechanical prosthesis IE - observe tiny oscilating structures on the atrial side (vegetations) - TEE

Video 18b Focused mechanical prosthesis with mobile vegetations in the same patient - TEE

Video 19 Mitral mechanical prosthesis IE in another patient - 2 mobile vegetations documented (11-12´clock) - TEE

Video 20a IE affecting mechanical prostheses in mitral (vegetation oscilating to left atrium) and aortic position (vegetation oscilating to left ventricle) - TEE

Image 20b Size of the vegetation on mitral mechanical prosthesis

Image 20c Size of the vegetation on aortic mechanical prosthesis

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Right sided endocarditis

Video 21a Large mobile vegetation on a septal leaflet of a tricuspid valve in a patient with IE - TTE A4C

Video 22a Another patient with tricuspid valve IE- large vegetation visible already on TTE 

Video 22b Large vegetation causing severe tricuspid regurgitation in the same patient

Video 22c Large vegetations seen on TEE in the same patient

Video 23a IE after tricuspid valve anuloplasty - mobile vegetation seen already on TTE

Video 23b Mobile vegetation located on anuloplasty by the free right ventricular wall seen on TEE in the same patient

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Implantable device endocarditis

Video 24 Large lobular vegetation on a pacemaker ventricular lead in the close proximity of a tricuspid valve (30x17mm)

Video 25 Large mobile vegetations on a stimulation system in a right atrium in a patient with CDRIE

Video 26a Large vegetation on a stimulatiuon system in another patient with CDRIE

Image 26b Size of the vegetation

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References

1. Yallowitz AW, Decker LC. Infectious Endocarditis. 2021 May 1. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan–. PMID: 32491573.
2. Rajani R, Klein JL. Infective endocarditis: A contemporary update. Clin Med (Lond). 2020 Jan;20(1):31-35. doi: 10.7861/clinmed.cme.20.1.1. PMID: 31941729; PMCID: PMC6964163.
3. Habib G, Badano L, Tribouilloy C, Vilacosta I, Zamorano JL, Galderisi M, Voigt JU, Sicari R, Cosyns B, Fox K, Aakhus S; European Association of Echocardiography. Recommendations for the practice of echocardiography in infective endocarditis. Eur J Echocardiogr. 2010 Mar;11(2):202-19. doi: 10.1093/ejechocard/jeq004. PMID: 20223755.
4. Steven A. Goldstein. Infective Endocarditis Role of Echo. Available from: https://asecho.org/wp-content/uploads/2017/10/09-Endocarditis-Florida_2017_Final.pdf
5. Baddour LM, Wilson WR, Bayer AS, Fowler VG Jr, Tleyjeh IM, Rybak MJ, Barsic B, Lockhart PB, Gewitz MH, Levison ME, Bolger AF, Steckelberg JM, Baltimore RS, Fink AM, O'Gara P, Taubert KA; American Heart Association Committee on Rheumatic Fever, Endocarditis, and Kawasaki Disease of the Council on Cardiovascular Disease in the Young, Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and Stroke Council. Infective Endocarditis in Adults: Diagnosis, Antimicrobial Therapy, and Management of Complications: A Scientific Statement for Healthcare Professionals From the American Heart Association. Circulation. 2015 Oct 13;132(15):1435-86. doi: 10.1161/CIR.0000000000000296. Epub 2015 Sep 15. Erratum in: Circulation. 2015 Oct 27;132(17):e215. Erratum in: Circulation. 2016 Aug 23;134(8):e113. Erratum in: Circulation. 2018 Jul 31;138(5):e78-e79. PMID: 26373316.
6. Nelson B Schiller, Bryan Ristow, Xiushui Ren. Role of echocardiography in infective endocarditis. Available from: www.uptodate.com
7. Infective Endocarditis: Practice Essentials, Background, Pathophysiology. Diseases & Conditions - Medscape Reference [online]. Available from: https://emedicine.medscape.com/article/216650-overview
8. Infective Endocarditis Echocardiography • LITFL • CCC Cardiology. LITFL • Life in the Fast Lane [online]. Copyright © 2021 LITFL [cit. 09.08.2021].Available from: https://litfl.com/infective-endocarditis-echocardiography/
9. Etiopathogenesis of Infective endocarditis – Histopathology.guru. Histopathology.guru – All about Pathology …… [online]. Copyright © All Rights Reserved. [cit. 09.08.2021]. Available from: https://www.histopathology.guru/etiopathogenesis-of-infective-endocarditis/

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