Journal of Cardiothoracic Surgery (Dec 2017)

Myocardial inflammation, injury and infarction during on-pump coronary artery bypass graft surgery

  • Shirjel R. Alam,
  • Colin Stirrat,
  • Nick Spath,
  • Vipin Zamvar,
  • Renzo Pessotto,
  • Marc R. Dweck,
  • Colin Moore,
  • Scott Semple,
  • Ahmed El-Medany,
  • Divya Manoharan,
  • Nicholas L. Mills,
  • Anoop Shah,
  • Saeed Mirsadraee,
  • David E. Newby,
  • Peter A. Henriksen

DOI
https://doi.org/10.1186/s13019-017-0681-6
Journal volume & issue
Vol. 12, no. 1
pp. 1 – 10

Abstract

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Abstract Background Myocardial inflammation and injury occur during coronary artery bypass graft (CABG) surgery. We aimed to characterise these processes during routine CABG surgery to inform the diagnosis of type 5 myocardial infarction. Methods We assessed 87 patients with stable coronary artery disease who underwent elective CABG surgery. Myocardial inflammation, injury and infarction were assessed using plasma inflammatory biomarkers, high-sensitivity cardiac troponin I (hs-cTnI) and cardiac magnetic resonance imaging (CMR) using both late gadolinium enhancement (LGE) and ultrasmall superparamagnetic particles of iron oxide (USPIO). Results Systemic humoral inflammatory biomarkers (myeloperoxidase, interleukin-6, interleukin-8 and c-reactive protein) increased in the post-operative period with C-reactive protein concentrations plateauing by 48 h (median area under the curve (AUC) 7530 [interquartile range (IQR) 6088 to 9027] mg/L/48 h). USPIO-defined cellular myocardial inflammation ranged from normal to those associated with type 1 myocardial infarction (median 80.2 [IQR 67.4 to 104.8] /s). Plasma hs-cTnI concentrations rose by ≥50-fold from baseline and exceeded 10-fold the upper limit of normal in all patients. Two distinct patterns of peak cTnI release were observed at 6 and 24 h. After CABG surgery, new LGE was seen in 20% (n = 18) of patients although clinical peri-operative type 5 myocardial infarction was diagnosed in only 9% (n = 8). LGE was associated with the delayed 24-h peak in hs-cTnI and its magnitude correlated with AUC plasma hs-cTnI concentrations (r = 0.33, p 10-fold the 99th centile upper limit of normal that is not attributable to inflammatory or ischemic injury alone. Peri-operative type 5 myocardial infarction is often unrecognised and is associated with a delayed 24-h peak in plasma hs-cTnI concentrations.

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