Incidence and predictive value of postoperative Troponin elevation in high-risk patients undergoing major thoracic surgery
Coronado Silva C.C., Morales P., Cano E., Vázquez C., González-Tallada A., de Nadal M.
Hospital Universitari Vall d'Hebron. Universitat Autònoma de Barcelona, Dept of Anaesthesiology & Intensive Care, Barcelona, Spain
Background and Goal of Study: Cardiac troponins are considered reliable biomarkers of myocardial injury in patients who undergo thoracotomy and lung surgery (1).Troponin elevation has been associated with intrapericardial resections and pneumonectomies but the incidence reported and its predictive value largely varies upon series (2,3).The aims of this study were to determine the frequency of postoperative troponin elevation following major thoracic surgery in high-risk patients and its correlation with the extension of the procedure and 30-day mortality. 
Material and methods: As part of routine postoperative care for patients at high cardiac risk (≥65 years or < 65 years with known cardiovascular pathology), we measured serum high-sensitivity Troponin I (TnI) levels (Siemens ADVIA Centaur) during the first two postoperative days in 117 consecutive patients undergoing major thoracic surgery. The TnI cut off used to define troponin elevation was the 99th percentile provided by our laboratory (TnI ≥0.04 ng/ml). Baseline clinical characteristics, perioperative parameters, and 30-day mortality were assessed in both groups.
Results and discussion: From January 2014 to October 2015, 117 high-risk patients underwent postoperative TnI monitoring after major thoracic surgery, of which 35 (25.7%) had a peak TnI ≥0.04 ng/ml on postoperative day 1 or 2. The frequency of TnI elevation was: pneumonectomy(3/5, 60%), lobectomy(26/70, 37.1%), wedge resection (5/26, 19.2%) or pleural resection(1/16, 8.3%) (P-value chi-squared 0.046). Active smoking was an independent factor for postoperative troponin elevation (P-value 0.028).No differences were found in age, sex or baseline clinical characteristics (including history of coronary artery disease) neither in perioperative parameters. Overall 30-day mortality was of 3/117(2.6%) and no difference was found between patients with or without postoperative troponin elevation (P-value 0.154). 
Conclusions: In our study, 25.7% of high-risk patients undergoing major thoracic surgery showed postoperative troponin elevation, being more frequent in more extensive procedures.This elevation was not associated with a higher risk of early mortality, suggesting that may be regulated by other mechanisms other than myocardial ischemia.Further studies are needed to confirm this issue.
References: 
1. Vikenes K et al. Int J Cardiol 2004; 96:403-7 
2. Muley et al. Clin Lab 2011; 57:925-932 
3. Lucrezioti et al. Rev Esp Cardiol 2007; 60:1159