Background
Postoperative pneumonia is a major cause of morbidity and mortality following cardiac
surgery. The inflammatory response to cardiac surgery has been widely studied, but
specific mechanisms for postoperative pneumonia have not been determined. Tranexamic
acid is renowned for its effect on bleeding but can also modulate inflammatory processes.
Cardiac surgery is known to release mitochondrial DAMPs (mtDAMPs) and is linked to
postoperative inflammation and atrial fibrillation. We speculated that mtDAMPs might
be related to postoperative pneumonia and that this might be modulated by tranexamic
acid.
Methods
Forty-one (41) patients from the Aspirin and Tranexamic Acid for Coronary Artery Surgery
(ATACAS) trial were studied. Levels of mitochondrial DNA, matrix metallopeptidase
9 (MMP-9) and neutrophil elastase (NE) were determined in plasma preoperatively, at
24 and 72 hours post-surgery and correlated with clinical outcome.
Results
mtDNA was significantly elevated postoperatively in the placebo and tranexamic acid
(TXA) groups. Neutrophil elastase increased immediately postoperatively and at 24
hours. MMP-9 was elevated in the placebo group early postoperatively and in the TXA
group at the immediate postoperative time point and after 24 hours. Six (6) of the
41 (14.6%) patients subsequently developed pneumonia. mtDNA levels were significantly
increased at the early postoperative period and the 24-hour time point in patients
with pneumonia.
Conclusions
Cardiac surgery releases mtDNA, increases MMP-9 and NE and this was not influenced
by TXA. Inflammation postoperatively might be linked to pneumonia since mtDNA was
further elevated in these patients. Due to the low number of individuals developing
pneumonia, further studies are warranted to clearly identify whether TXA impacts on
the inflammatory response in postoperative pneumonia.
Keywords
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Article info
Publication history
Published online: October 06, 2021
Accepted:
August 4,
2021
Received in revised form:
June 3,
2021
Received:
May 16,
2018
Identification
Copyright
© 2021 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.
