microRNA signatures of perioperative myocardial injury after elective non-cardiac surgery: prospective observational cohort study

BackgroundElevated plasma/serum troponin, indicating perioperative myocardial injury (PMI), is common after non-cardiac surgery. However, underlying mechanisms remain unclear. Acute coronary syndrome (ACS) is associated with the early appearance of circulating microRNAs, which regulate post-translational gene expression. We hypothesised that if PMI and ACS share pathophysiological mechanisms, common microRNA signatures should be evident.MethodsNested case-control study of samples obtained before and after non-cardiac surgery from patients enrolled in two prospective observational studies of PMI (postoperative troponin I/T>99th centile). In cohort one, serum microRNAs were compared between patients with/without PMI, matched for age, gender and comorbidity. Real-time polymerase chain reaction quantified relative microRNA expression (cycle quantification threshold ResultsMicroRNA were detectable in all 59 patients (median age:67yrs (61-75); 42% male), who had similar clinical characteristics independent of developing PMI. In cohort one, PMI was not associated with increased serum microRNA expression levels after surgery (hsa-miR-1-3p mean fold-change (FC):3.99 (95%CI:1.95-8.19); hsa-miR-133-3p FC:5.67(95%CI:2.94-10.91); pConclusionsCirculating microRNAs synonymous with cardiac ischaemia were universally elevated in patients after surgery, independent of developing myocardial injury.