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Prosthetic Aortic Valve Endocarditis by Neisseria Elongata after Bentall Procedure: When Multimodality Imaging is Key to Diagnosis

Keywords
Infective endocarditis; Neisseria elongata; Bentall procedure; Prosthetic valve; Multimodality imaging

A diabetic 65-year-old male with previous Bentall procedure and mechanical aortic valve prosthesis presented with fever and abdominal pain, along with systolic murmur (III/VI) and elevated inflammatory markers. Abdominal computed tomography (CT) revealed splenic infarction. Transesophageal echocardiogram (TEE) was negative for vegetations. Given the persistent suspicion of infective endocarditis (IE) with peripheral embolism, empirical antimicrobial therapy was initiated. The patient subsequently presented with complete atrioventricular block, requiring temporary transvenous pacing. An epicardial pacemaker was later implanted.

At the time, cardiac CT revealed an irregular-shaped hypoattenuating mass attached to the ventricular side of the prosthetic suture ring, consistent with vegetation (Figure 1A), interfering with the normal opening of one of the prosthesis discs (Video 1). Repeat TEE also showed a small highly mobile vegetation and an annular abscess in the prosthetic aortic valve (Figure 2). Blood cultures were positive for Neisseria elongata, confirming the diagnosis of prosthetic valve endocarditis (PVE); antimicrobial therapy was tailored. Despite early improvement, the patient later presented with de novo ataxia and brain CT revealed infarction in the right vertebrobasilar territory. New sets of cultures remained negative and coagulation levels were within therapeutic range. A small vegetation persisted on cardiac CT and TEE, and inflammatory infiltrate was apparent at the mitro-aortic curtain.

Figure 1
1A) Cardiac CT scan at admission showing vegetation in the aortic valve and inflammatory changes in the intervalvular fibrosa and inter-atrial septal spaces. 1B) Cardiac CT scan at discharge with residual inflammatory tissue.
Figure 2
2A) Transesophageal echocardiogram, midesophageal long-axis aortic valve plane. (a) Vegetation (red arrow) and inflammatory infiltrate (white arrow). (b) Annular abscess (red arrow). Ao: ascending aorta; LA: left atrium; LV: left ventricle. 2B) Transesophageal echocardiogram at discharge, midesophageal long-axis aortic valve plane. No vegetation or abscess visible. Ao: ascending aorta; LA: left atrium; LV: left ventricle.

The patient was refused for surgery due to the prohibitively high risk of re-operation, and a conservative strategy was pursued after Heart Team discussion. Following eight weeks of antimicrobial therapy, clinical and laboratory remission were achieved. CT scan disclosed a normally functioning prosthesis (Video 2) and the previously observed pathological findings were absent (Figure 1B). Vegetations were no longer evident on TEE (Figure 3).

The patient remained asymptomatic at 1-year follow-up, without echocardiographic or laboratory signs of recurrence.

This is, to our knowledge, the first case report of PVE in a patient with previous Bentall procedure due to Neisseria elongata. We highlight the importance of multimodality imaging, particularly when diagnosis remains uncertain after inconclusive echocardiographic evaluation. The diagnosis ultimately relied on CT findings, included as a major diagnostic criterion in the latest endocarditis guidelines.11. Habib G, Lancellotti P, Antunes MJ, Bongiorni MG, Casalta J-P, Del Zotti F 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). Eur Heart J. 2015; 36(44):3075–128. CT has excellent spatial resolution and enables detailed visualization of paravalvular anatomy and complications, with less artifact and shadowing from the prosthesis.22. Cahill TJ, Baddour LM, Habib G, Hoen B, Salaun E, Pettersson GB et al. Challenges in Infective Endocarditis. J Am Coll Cardiol. 2017; 69(3):325-44.

Despite the obvious surgical indications, the patient was successfully treated with a conservative (controversial) strategy. Although removal and replacement of prosthetic material was traditionally considered mandatory, if intervention is not feasible, patients should be treated with prolonged antibiotic therapy.33. Machelart I, Greib C, Wirth G, Camou F, Issa N, Vialland JF, et al. Graft infection after a Bentall procedure: A case series and systematic review of the literature. Diagn Microbiol Infect Dis. 2017; 88(2):158–62. Multiple series, including the ESC-EORP EURO-ENDO registry,44. Habib G, Erba PA, Iung B, Donal E, Cosyns B, Laroche C et al. Clinical presentation, aetiology and outcome of infective endocarditis. Results of the ESC-EORP EURO-ENDO (European infective endocarditis) registry: a prospective cohort study. Eur Heart J. 2019; 40(39):3222-33. have stated the discrepancy between guideline-directed surgical indications and actual practice, largely explained by evermore complex patients, with more co-morbidities and previous interventions with intracardiac prosthetic material. This case is illustrative of the current challenges involved in the diagnosis and management of PVE, where conservative treatment may sometimes prove successful and the only acceptable option.

  • Sources of Funding
    There were no external funding sources for this study.
  • Study Association
    This study is not associated with any thesis or dissertation work.
  • Ethics Approval and Consent to Participate
    This article does not contain any studies with human participants or animals performed by any of the authors.

Referências

  • 1
    Habib G, Lancellotti P, Antunes MJ, Bongiorni MG, Casalta J-P, Del Zotti F 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). Eur Heart J. 2015; 36(44):3075–128.
  • 2
    Cahill TJ, Baddour LM, Habib G, Hoen B, Salaun E, Pettersson GB et al. Challenges in Infective Endocarditis. J Am Coll Cardiol. 2017; 69(3):325-44.
  • 3
    Machelart I, Greib C, Wirth G, Camou F, Issa N, Vialland JF, et al. Graft infection after a Bentall procedure: A case series and systematic review of the literature. Diagn Microbiol Infect Dis. 2017; 88(2):158–62.
  • 4
    Habib G, Erba PA, Iung B, Donal E, Cosyns B, Laroche C et al. Clinical presentation, aetiology and outcome of infective endocarditis. Results of the ESC-EORP EURO-ENDO (European infective endocarditis) registry: a prospective cohort study. Eur Heart J. 2019; 40(39):3222-33.

Publication Dates

  • Publication in this collection
    17 May 2021
  • Date of issue
    May 2021

History

  • Received
    25 June 2020
  • Reviewed
    05 Sept 2020
  • Accepted
    09 Nov 2020
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