CARDIOVASCULAR JOURNAL OF AFRICA • Vol 24, No 3, April 2013
e8
AFRICA
Antifungal therapy with caspofungin (70 mg intravenous
loading dose, followed by 50 mg/day) was started according to
the demonstrated antibiogram susceptibility (MIC 0.25 mg/l).
After more positive blood cultures, despite antifungal therapy, the
patient underwent surgery for prosthetic aortic valve replacement
(Bioprothesis Sorin Mitroflow 21 mm) with aortic annular
reinforcement using an autologous pericardial patch, since there
was intra-operative evidence of aortic annulus involvement and
diffused prosthetic valve vegetations (Fig. 2). On the sixth post
operative day, the patient was moved to the Infectious Diseases
Unit without fever.
No neurological dysfunction occurred during the peri-
operative period. After one week, a new series of blood cultures
was negative, and no episodes of fever occurred during the
following 12 months.
Currently, the patient is in good clinical condition, and she
is still on antifungal therapy (oral fluconazole 200 mg/day),
with diagnostic examinations performed every six months
(transthoracic echocardiogram, blood cultures, complete blood
count, and markers of inflammation, renal and liver function).
In the absence of renal and liver dysfunction, we routinely
recommend antifungal therapy for at least two years after
surgery, to avoid recurrence of FE.
Discussion
Fungal endocarditis is uncommon and predominantly caused by
Candida
species, and less frequently by
Aspergillus
species.
C
albicans
is found in 46% of cases of FE, while
C parapsilosis
is
found in 17%.
1
FE is known to be a high-risk condition for septic
embolism and is associated with a poorer prognosis compared
with bacterial endocarditis. Moreover, recurrence of fungal
infection occurs in almost 30% of patients even after completion
of the appropriate therapy.
5
Risk factors for FE include extensive surgery, prolonged
hospitalisation and invasive medical procedures, although the
most important predisposing factor appears to be the use of
intravenous drugs. In the latter case,
C parapsilosis
is the most
common aetiological agent, with a specific ability to generate a
biofilm that tends to cover non-biological surfaces; this could
explain its high association with the presence of intravascular
devices.
5
In the last 20 years, 72 cases of FE were caused by
C
parapsilosis
, of which 26 on prosthetic heart valves have been
reported.
4
Half of the patients were treated with antifungal
therapy alone. A surgical approach is advised depending on the
patient’s clinical status and on the echocardiographic findings.
Echocardiography is useful not only to confirm the diagnosis,
but also for the decision-making process and for surgical timing.
Sometimes, huge vegetations with a high embolic potential,
or signs of significant valve dysfunction can be detected, thus
leading to urgent or emergency surgery.
The combination of antifungal chemotherapy and surgical
removal of the diseased valve is the most accepted therapeutic
strategy for patients with FE.
2,5
However, in some instances,
medical therapy alone with modern antifungal agents has been
demonstrated to be sufficient to obtain complete healing of
the prosthetic valve, unless friable vegetations are identified at
echocardiography.
Nonetheless, in our case, medical therapy failed to resolve
the fungaemia, and no evidence of endocarditis was identified
on echocardiography before the operation, while at surgery
the prosthetic valve was found to be extensively covered by
vegetations. False negatives at echocardiography appear to be
relatively common and surgery should always be considered
when dealing with FE on prosthetic heart valves, even in the
absence of a clear demonstration of vegetations.
A possible explanation could be that if the vegetations are
present predominantly inside the struts, they are not mobile, and
consequently are not easily visualised, as in the present case.
Therefore, this possibility should be suspected and specifically
addressed in the diagnostic process. The use of three-dimensional
echocardiography should be considered for atypical cases of
infective endocarditis, to improve the accuracy of the diagnostic
evaluation.
6,7
Conclusion
We believe that diagnostic imaging may underestimate the entity
of prosthetic valve involvement during FE. Given the limited
evidence for the success of medical therapy alone, and the failure
of 2D echocardiography to reveal the severity of disease in our
patient, early surgical exploration should be considered when a
prosthetic heart valve FE is diagnosed, to speed resolution of the
disease and to prevent embolism from unidentified vegetations.
References
1.
Bayer AS, Bolger AF, Taubert KA, Wilson W, Steckelberg J, Karchmer
AW,
et al
. Diagnosis and management of infective endocarditis and its
complications. Circulation 1998;
98
: 2936–2948.
2.
Habib G, Hoen B, Tornos P, Thuny F, Prendergast B, Vilacosta I,
et
al
. Guidelines on the prevention, diagnosis, and treatment of infective
endocarditis.
Eur Heart J
2009;
30
: 2369–2413
3.
Donal E, Abgueguen P, Coisne D, Gouello J, McFadden E, Allal J,
et al
. Echocardiographic features of
Candida
species endocarditis: 12 cases
and a review of published reports.
Heart
2001;
86
: 179–182.
4.
Garzoni C, Nobre VA, Garbino J.
Candida parapsilosis
endocarditis:
a comparative review of the literature.
Eur J Clin Microbiol Infect Dis
2007;
26
: 915–926.
5.
Ellis ME, Al-Abdely H, Sandridge A, Greer W, Ventura W. Fungal
endocarditis: evidence in the world literature, 1965–1995
. Clin Infect
Dis
2001;
32
: 50–62.
6.
Pérez de Isla L, Zamorano J, Malangatana G, Almería C, Rodrigo JL,
Cordeiro P, Macaya C. Usefulness of real-time 3-dimensional echocar-
diography in the assessment of infective endocarditis: initial experience.
J Ultrasound Med
2005;
24
: 231–233.
7.
Caselli S, Mazzesi G, Tritapepe L, Barretta A, Pandian NG, Agati L,
Fedele F. 3D echocardiographic delineation of mitral–aortic intervalular
fibrosa pseudoaneurysm caused by bicuspid aortic valve endocarditis.
Echocardiography
2011;
28
: E1–4.
Fig. 2. Bioprosthetic valve with diffuse vegetations inside
the strut: (a) ventricular and (b) aortic views.
A
B
