Intraoperative management and postoperative course
Surgical inspection revealed thick and pervasive, green-yellow membranes
covering the entire heart, great vessels, diaphragm, both lungs as well
as the entire chest wall (Fig. 1). The turf also covered contained
ruptures of aorto-aortic anastomosis and the previously constructed
end-to-side anastomosis of the LVAD arterial return to the native
ascending aorta.
Remains of the vascular prosthesis were removed and the aorto-aortic
anastomosis could be re-sutured due to sufficient length of the
ascending aorta. Extensive debridement of all anatomical structures of
the thoracic cavity was performed and \souta Negative Pressure Wound
Therapy (NPWT) was applied.
Histopathological examination (Fig. 2), cultures as well as genomic
sequencing of all specimens including pleural fluid uniformly revealedA. fumigatus . Galactomannan test was positive (EIA index 0.1),
but bacterial fungal as well as blood cultures revealed no other
microorganisms. CT-scan revealed no other organ involvement by invasive
aspergillosis.
In lack of a literature report on any similar case with such extensiveAspergillus mediastinitis we empirically decided to pursue the
following treatment. Surgical wound re-opening every third day, sharp
and blunt mechanical scrubbing and cleaning of the fungal turf, topical
application of voriconazole and chlorhexidine 2%, 20-fold diluted
(resulting in chlorhexidine 0.01%), dunking the entire thoracic cavity
for 40 minutes with each drug (Fig. 3) and an open chest treatment with
NPWT between the re-explorations. Pre-emptive systemic antifungal
therapy with a combination of caspofungin and voriconazole was started.
Following susceptibility testing and determination of minimal inhibitory
concentration (MIC 0.125mg/l), voriconazole was continued at a serum
concentration of 4-6mg/l. The immunosuppressive regimen was tailored and
potential organ rejection surveyed by echocardiography. Debridement and
topical therapy was performed eight times. As by visible involvement of
the sternal bone tissue, 5mm of each sternal side was removed,
histopathology confirming A. fumigatus .
After the fourth surgical session, consistent with marked visible
decrease of the fungal turf overspreading the mediastinal organs,
repeated microscopic and microbiological examinations were found to be
sterile with regard A.fumigatus. However, colonization with
multi-drug resistant Acinetobacter baumannii susceptible only to
polymyxin B (MIC 0.5mg/l) was detected in the sixth session. Hence, a
diluted colistin-solution was applied topically to the thoracic cavity
and infected structures and colistin was administered intravenously for
one week. The postoperative course between each surgical session was
uneventful, the patient remaining isolated but fully mobilized on the
regular ward.
After eight surgical revisions revealing clean intrathoracic tissues on
gross examination and negative microbiological findings with respect toA. fumigatus , definite wound closure was achieved 26 days after
the first revision with a latissimus dorsi muscle flap plasty to
fill the persistent left-sided thoracic cavity. Sternal refixation and
wound closure were performed according to our infection-prevention
protocol (sternal wound irrigation with vancomycin wax and gentamycin
solution). Careful reversal of immunosuppression allowed a stable
cardiovascular course without any signs of rejection checked by repeated
endomyocardial biopsy and echocardiography. The patient was discharged
47 days after our first surgical intervention with uneventful
postoperative recovery and wound healing. Oral voriconazole with regular
monitoring of liver function was continued for 12 months, cardiac
medication and immunosuppression are continued corresponding to
state-of-the-art. One year after wound closure, no findings suspicious
for persistent or recurrent fungal infection on chest X-ray and CT-scan
and negative serum galactomannan were reported. The patient is in
excellent condition with good functional capacity, normal biventricular
function, normal coronary angiography and no signs of cardiac rejection,
seven years after this episode of mediastinitis.