Post-cardiac surgery fungal mediastinitis: clinical features, pathogens and outcome

Objectives The occurrence of mediastinitis after cardiac surgery remains a rare and severe complication associated with poor outcomes. Whereas bacterial mediastinitis have been largely described, little is known about their fungal etiologies. We report incidence, characteristics and outcome of post-cardiac surgery fungal mediastinitis. Methods Multicenter retrospective study among 10 intensive care units (ICU) in France and Belgium of proven cases of fungal mediastinitis after cardiac surgery (2009–2019). Results Among 73,688 cardiac surgery procedures, 40 patients developed fungal mediastinitis. Five were supported with left ventricular assist device and five with veno-arterial extracorporeal membrane oxygenation before initial surgery. Twelve patients received prior heart transplantation. Interval between initial surgery and mediastinitis was 38 [17–61] days. Only half of the patients showed local signs of infection. Septic shock was uncommon at diagnosis (12.5%). Forty-three fungal strains were identified: Candida spp. (34 patients), Trichosporon spp. (5 patients) and Aspergillus spp. (4 patients). Hospital mortality was 58%. Survivors were younger (59 [43–65] vs. 65 [61–73] yo; p = 0.013), had lower body mass index (24 [20–26] vs. 30 [24–32] kg/m 2 ; p = 0.028) and lower Simplified Acute Physiology Score II score at ICU admission (37 [28–40] vs. 54 [34–61]; p = 0.012). Conclusion Fungal mediastinitis is a very rare complication after cardiac surgery, associated with a high mortality rate. This entity should be suspected in patients with a smoldering infectious postoperative course, especially those supported with short- or long-term invasive cardiac support devices, or following heart transplantation.