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

2. 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

3. 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

4. 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

5. 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

6. 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

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

8. Results 3: adjusted mortality

9. 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

10. 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

11. 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

12. 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.

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

14. Further reading