Myocardial Injury After Noncardiac Surgery tied to Preoperative Anaemia: Study

Preoperative anaemia is associated with adverse outcomes of noncardiac surgery, but its association with myocardial injury after noncardiac surgery (MINS) has not been fully investigated. Therefore, Dr Ji-Hye Kwon and her team conducted a study to evaluate the association between preoperative anaemia and MINS.

It was a single-centre retrospective cohort study of data from the tertiary care referral centre. The researchers included a total of 35 170 patients with measured cardiac troponin (cTn) I levels after noncardiac surgery. They were separated according to preoperative anaemia (haemoglobin <13 g dl−1 in men and <12 g dl−1 in women). Among 35 170 patients, 22 062 (62.7%) patients were in the normal group and, 13 108 (37.3%)were in the anaemia group. The researchers further stratified anaemia into mild and moderate-to-severe at a haemoglobin level threshold of 11 g dl−1. After propensity score matching, 11919 sets of patients were generated. The major outcome assessed was MINS, defined as a peak cTn I level more than 99th percentile of the upper reference limit within 30 postoperative days.

Key findings of the study were:

• Upon evaluation, the researchers found that the incidence of MINS was significantly associated with anaemia [14.5 vs 21.0%, odds ratio (OR) 1.57].
• Using multivariable analysis, they found a graded association between anaemia severity and MINS (OR 1.32 for mild anaemia and OR 1.80 for moderate-to-severe anaemia compared with the normal group).
• They also found a significantly higher incidence of MINS for moderate-to-severe anaemia than mild anaemia (18.6 vs 28.6%, OR 1.37).
• They noted that the estimated threshold for preoperative haemoglobin associated with MINS was 12.2 g dl−1, with an area under the curve of 0.622.

The authors concluded, "Preoperative anaemia was independently associated with MINS, suggesting that MINS may be related to the association between anaemia and postoperative mortality."

For further information:

DOI: 10.1097/EJA.0000000000001421