Myocardial Injury after Noncardiac Surgery and Association with Short Term Mortality Wilton A van Klei Anesthesiologist and acting chair Department Anesthesiology, UMC Utrecht

University Medical Center Utrecht (NL) University teaching hospital 1000 beds Adults hospital Childrens hospital Dutch military hospital Medical faculty 30 surgical suites All types of surgery 25,000 procedures / year

Postoperative troponin measurements Meta-analysis (Levy etal Anesthesiology 2011) Increased troponin after surgery is a predictor of mortality Intensive postoperative troponin monitoring? VISION study (JAMA 2012) Increased troponin after surgery is associated with mortality Monitoring postoperative troponin enhances risk stratification Third universal definition MI (Thygesen etal, Circulation 2012) Routine monitoring of cardiac biomarkers in high-risk patients, both prior to and after major surgery, is recommended

Implementation of routine postoperative troponin measurement monitoring Introduction January 2011 Clinical protocol All intermediate and high-risk noncardiac surgery Age 60 or greater General or spinal anesthesia Postoperative admission at least 24h Troponin measurements day 1, 2 and 3 Elevated -> ward physician notified Additional tests / cardiology consultation left at discretion of attending physician

Determinant and outcomes Definition of postoperative myocardial injury Troponin I (3rd generation Beckman Coulter) Cut-off > 60 ng/L Outcomes All cause 30-day mortality Incidence of postoperative myocardial infarction Postoperative length of stay

Results 1: patients Eligible patients 2232 Lost to follow-up 16 (0.7%) Myocardial injury and age Eligible patients 2232 Lost to follow-up 16 (0.7%) Included patients 2216 Tn according to protocol 1627 (73%) Myocardial injury (Tn >60 ng/L) 315 (19%) Over 50% elevations on first postop day Incidence increased with increasing age

Results 2: crude mortality 30-day mortality yes no total Myocardial injury yes 27 (8.6%) no 29 (2.2%) 288 1283 315 1312

Results 3: adjusted mortality

Results 4: clinical course of patients Elevated troponin 315 Myocardial infarction 10 (3.2%) Coronary Care Unit 8 Angiography 7 PCI 4 CABG 1 ECG changes new ischemia 30 (9.5%) ST elevation (STEMI) 1 ST depression > 1 mm 14 Repolarization changes 15 Median postoperative length of stay was 10 days, compared to 5 days in patients without myocardial injury Median time to death after elevated troponin was almost 2 weeks

Results 5: summary One of the first studies showing results of implementation of routine postoperative monitoring of troponin Tn elevation in 19%, and Tn elevation was an independent predictor of 30-day mortality Association was dependent on the degree of Tn elevation but independent of preoperative factors Most of the patients with myocardial injury did not show any clinical symptoms and ECG changes are often not found

Discussion Preoperative troponin measurement not available New protocol not always followed (it takes time to implement) Often unintentionally not ordered after emergency surgery Results of sensitivity analysis after multiple imputation did not change results Results comparable to those from VISION study The improved risk discrimination of patients with primarily asymptomatic myocardial injury, together with the time interval between troponin I elevation and death (2 weeks), may allow physicians to modify prognosis

Future To modify prognosis, the underlying pathophysiological mechanisms of postoperative myocardial injury must be explored. In addition, it must be elucidated whether there is a causal relationship between myocardial injury and mortality or whether myocardial injury merely indicates a worse outcome whether patients with myocardial injury may benefit from postoperative cardiovascular treatment.

Acknowledgements Funding International Anesthesia Research Society – Clinical Scholar Research Award 2011 Friends of the University Medical Center Utrecht Foundation Departmental

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