Does Troponin T predict non-cardiac complications after major abdominal surgery?

High-sensitive cardiac troponin T measurements in prediction of non-cardiac complications after major abdominal surgery. Noordzij P, Van Geffen O, Dijkstra I, et al. Br J Anaesth. 2015 Jun;114(6):909-18. doi: 10.1093/bja/aev027.

Background

Postoperative non-cardiac complication rates are as high as 11–28% after high-risk abdominal procedures. Evidence of a relationship between raised post-op high-sensitive troponin and non-cardiac complications after major abdominal surgery. Based on previous studies relating troponin rise in the first 3 days post-op following a vascular surgery was associated with high mortality despite patients are asymptomatic. Vision Study has re-discovered that minor elevations of cTnT predicted 30 day postoperative mortality and more marked elevation were incrementally associated with high mortality. Similar studies by Beattie and colleagues and Van Waes and Colleagues recently had shown troponin elevations in the first days post-op are common and strongly predict both 30 day mortality and longterm mortality. Noordzij and colleagues focused on non cardiac complications.

Method

Prospective observational single-centre cohort study. Patients at risk of for coronary artery disease undergoing major elective abdominal surgery. Troponin levels measured before surgery and at day 1, 3 and 7. Multivariable logistic regression analysis was performed to examine the adjusted association for different cut off concentrations of post-operative myocardial injury & non-cardiac outcome.

Recruitment at a Teaching Hospital over a period of 18 months. n=210, 7 excluded. Patients identified at pre-assessment clinic.

Eligibility

  • Patients undergoing major elective abdominal surgery with mortality risk >3%
  • Age >45
  • One of the following criteria: DM, PVD, hospitalisation for congestive heart failure, myocardial infarct, stable angina, hx of bypass or angioplasty, creatinine >150, AS valve area <1cm2, AF and EF <55
  • 2 of minor risk factors: age>70, HTN, hyperchol, TIA, COPD, smoking or low functional CapacityPre-op use of cardiovascular drugs

End points
Occurrence of non cardiac events within 30 days after surgery: mortality sepsis/SIRS, anastomotic dehiscence, bowel ischaemia, wound infection and bleeding

Results

Myocardial injury after major abdominal surgery is common & associated with adverse non-cardiac 30 day outcome.
Relative increase in cTnT >100% is a superior independent predictor of noncardiac 30 day complications compared to their cut-offs.

Strengths

In summary, postoperative non-cardiac and cardiac complications correlating with low-levels and higher-levels postoperative troponin elevations, respectively, are two sides of the same spectrum of events. Non-cardiac complications pose a higher demand on the patient’s heart, and thus, it is not surprising that mortality is increased in those with underlying heart disease, which is often marked by an elevated cTn. Conversely, primary cardiac injury may lead to cardiac failure and a deterioration in other important systems, such as the kidneys, leading to what may appear to be a non-cardiac cause of death.

Our important role in the future is to develop ways to understand the specifics of both situations so that we can devise treatment strategies that take both cardiac and non-cardiac issues into account and improve patient care.

Limitations

Sample size was small, and single centre. The inclusion criteria did not consider peri-operative events to have an effect on outcomes. The type of surgery was not uniform and some of the surgeries were following ERAS protocols therefore, large differences in pre, peri and postoperative management.

Would it change my practice?

It is a promising study however, the evidence is not sufficient to help with preoperative risk stratification. Larger multi-centre studies would be beneficial.

 

Summary by Dr Dina Hadi

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