ABSTRACT:
Fungal endocarditis/aortitis is an uncommon yet emerging entity
accounting for 2% to 4% of all cases of infective endocarditis and
continues to be associated with a poor prognosis. We present here the
first case of polyethylene-terephthalate (PETE) graft aortitis caused by
A. Niger, a rare fungal agent responsible for the Aspergillus aortitis.
Early diagnosis with frequent transoesophageal echocardiography (TEE)
and a prompt surgical intervention coupled with optimal antifungal
therapy are still the only option to reduce the exceedingly high
mortality and morbidity.
INTRODUCTION
Aspergillus is an opportunistic nosocomial fungus generally
associated with a high mortality rate 1. WhileA. fumigatus has been reported to be the most frequent cause of
aspergillosis, A. Niger has been rarely associated with infection
and only few cases have been reported in patients who have recently
undergone valvular heart surgery2-5 and pacemaker
implantation 6, as well as in patients with neoplastic
diseases, intravenous treatment or drug addiction, long-term parenteral
feeding and immunosuppression.
CASE REPORT
A 38-year-old man with a history of congenital aortic valve stenosis
underwent a mechanical aortic valve replacement (21 mm SJ Regent) with
aortotomy’s closure by a pericardium patch at an external center. The
postoperative period was impacted by sporadic serotine fever treated
with empiric antibiotic therapy but two months after surgery he was
referred to our center due to enduring low-grade fever and mild
leucocytosis; apart from these signs his physical examination was
unremarkable and there were no signs of petechiae, splenomegaly or
clubbing. All microbiological evaluations were uneventful,
transoesophageal echocardiography (TEE) examination showed no
endocarditis signs but computerized tomography (CT) scan unveiled a
pseudo-aneurysmatic degeneration (6.5 x 5.3 centimetres) on the aortic
wall in correspondence of the aortotomy’s suture. Reoperation was
decided upon and he underwent an ascending aortic replacement with
polyethylene-terephthalate (PETE) 28 mm Hemashield graft; no suggestive
signs of active infection were detected in the pericardial patch,
therefore coltural examination of the sample was not performed. He was
discharged in excellent condition but after 7 months he was re-admitted
to our center for new onset of fever and malaise, distal leg and spleen
embolization and high levels of inflammatory biomarkers. In cardiac
auscultation, cardiac sounds were rhythmic and metallic valve sound was
heard. The TEE showed a regular aortic prosthesis, the CT scan a
peri-aortic exudation without enhancement and the positron emission
tomography (PET) confirmed an aspecific postoperative inflammatory
exudate around the graft. All four blood culture sets were negative as
were serology for rickettsia and Q fever; the patient was treated
empirically with Vancomycin and Ceftriaxone and thus fever subsided and
two different TEEs confirmed no sign of endocarditis. Although three
weeks of antibiotic therapy, inflammatory biomarkers increased again and
for the first time TEE revealed two mobile masses (15 x 16 mm each),
suggestive of vegetations, with a stalk at the ascending aorta graft
wall (Figure 1A, B; Supp Video) one centimetre around over the right
coronary ostium without evidence of valvular damage; a new CT scan
confirmed the diagnosis showing a 8 mm filling defect in the same
position (Figure 1C, D). All six blood culture sets were negative and
with the diagnosis of culture-negative graft aortitis caspofungin was
administered due to the β-d-glucan (BDG) positivity; thus a new surgery
was performed with aortic homograft root implantation: intraoperative
exploration confirmed the aortitis of the PETE prothesis and the
resected material was sent to our microbiology laboratories that
revealed A. Niger infection. The patient’s hemodynamic has been
supported by dobutamine for 8 days and heart rate by temporary
epicardial ventricular pacing due to third-degree atrioventricular block
with following spontaneous recovery with sinus rhythm. The patient
received parenteral liposomal amphotericin-B (5 mg/kg per day) for 45
days followed by oral voriconazole for another 6 months with good
clinical evolution. The six-month follow-up TEE showed no
endocarditis/aortitis and all the inflammatory biomarkers were negative.
COMMENT
Fungal endocarditis/aortitis is an uncommon yet emerging entity
accounting for 2% to 4% of all cases of infective endocarditis and
continues to be associated with a poor prognosis 7.A. Fumigatus is the most common fungal agent responsible for the
Aspergillus aortitis and its diagnosis is very difficult. Blood cultures
are negative in over 50% of cases, β‐D‐glucan has a sensitivity and
specificity of 69.9% and 87.1% respectively 7 and
the infection may be overlooked by transthoracic echocardiography as it
localizes in the ascending aorta. This represents the fourth case ofA. Niger aortitis 4,5,8, the first one
involving a PETE graft. The only predisposing factor for A. Nigerinfection in this patient was the first open heart surgery. AlthoughA. Niger mycotic endocarditis/aortitis is rare among
immunocompetent patients, the diagnosis should be considered for all
patients with fever and an unidentified infection origin who have had
heart surgery. The case emphasizes the role of serial TEEs in the
diagnosis and management of these patients particularly with negative
cultures and it illustrates the possible insidious course of fungal
endocarditis/aortitis that continues to be associated with a poor
prognosis. Early diagnosis and a prompt surgical intervention coupled
with optimal antifungal therapy are still our only option to reduce the
exceedingly high mortality and morbidity.
Acknowledgments and Disclosures:none