Prediction of perioperative myocardial infarction/injury in high-risk patients after noncardiac surgery

Abstract

Aims: Perioperative myocardial infarction/injury (PMI) is a surprisingly common yet difficult-to-predict cardiac complication in patients undergoing noncardiac surgery. We aimed to assess the incremental value of preoperative cardiac troponin (cTn) concentration in the prediction of PMI.

Methods and results: Among prospectively recruited patients at high cardiovascular risk (age ≥65 years or ≥45 years with preexisting cardiovascular disease), PMI was defined as an absolute increase in high-sensitivity cTnT (hs-cTnT) concentration of ≥14 ng/L (the 99th percentile) above the preoperative concentration. Perioperative myocardial infarction/injury was centrally adjudicated by two independent cardiologists using serial measurements of hs-cTnT. Using logistic regression, three models were derived: Model 1 including patient- and procedure-related information, Model 2 adding routinely available laboratory values, and Model 3 further adding preoperative hs-cTnT concentration. Models were also compared vs. preoperative hs-cTnT alone. The findings were validated in two independent cohorts. Among 6944 patients, PMI occurred in 1058 patients (15.2%). The predictive accuracy as quantified by the area under the receiver operating characteristic curve was 0.73 [95% confidence interval (CI) 0.71-0.74] for Model 1, 0.75 (95% CI 0.74-0.77) for Model 2, 0.79 (95% CI 0.77-0.80) for Model 3, and 0.74 for hs-cTnT alone. Model 3 included 10 preoperative variables: age, body mass index, known coronary artery disease, metabolic equivalent >4, risk of surgery, emergency surgery, planned duration of surgery, haemoglobin, platelet count, and hs-cTnT. These findings were confirmed in both independent validation cohorts (n = 722 and n = 966).

Conclusion: Preoperative cTn adds incremental value above patient- and procedure-related variables as well as routine laboratory variables in the prediction of PMI.

Keywords: Diagnostic screening programme; High-sensitivity troponin; Perioperative care; Perioperative myocardial injury; Preoperative care; Troponin.

Graphical Abstract

ASA, American society of anesthesiology; AUC, area under the receiver operating characteristics curve; Hb, haemoglobin; Na, potassium; RCRI, revised cardiac risk index

Figure 1

Patient flow chart. Study population selection can be seen in this flow chart. Missing laboratory values included missing preoperative routinely available laboratory values, as well as missing preoperative hs-cTnT or s-cTnI values. PMI, perioperative myocardial infarction/injury; hs-cTnT, high-sensitivity cardiac troponin T; s-cTnI, sensitive cardiac troponin I.

Figure 2

Accuracy for the prediction of perioperative myocardial infarction/injury. Area under the receiver operating characteristic curve to compare the diagnostic accuracy of Model 3 with the RCRI, the ASA classification, and hs-cTnT alone (A). Area under the receiver operating characteristic curve quantifying the accuracy of the three prediction models in the derivation cohort (B). AUC, area under the receiver operating characteristic curve; RCRI, revised cardiac risk index; ASA, American Society of Anesthesiologists.

Figure 3

Examples for usage of the online calculator tool. A patient with age of 70 years, normal weight, no history of coronary artery disease or myocardial infarction, metabolic equivalent of task > 4, intermediate risk of surgery according to the European Society of Cardiology, elective surgery, planned duration of surgery of 100 min, no anaemia, normal level of thrombocytes, and a high-sensitivity cardiac troponin T of 3 ng/L has a risk of perioperative myocardial infarction/injury of 1.6% (A). A patient with age of 75 years, underweight, history of coronary artery disease without myocardial infarction, metabolic equivalent of task < 4, intermediate risk of surgery according to the European Society of Cardiology, elective surgery, planned duration of surgery of 150 min, mild-to-moderate anaemia, normal level of thrombocytes, and a high-sensitivity cardiac troponin T of 12 ng/L has a risk of perioperative myocardial infarction/injury of 20.7% (B). A patient with age of 80 years, overweight, history of coronary artery disease with myocardial infarction, metabolic equivalent of task < 4, high risk of surgery according to the European Society of Cardiology, urgent surgery <24 h, planned duration of surgery of 60 min, mild-to-moderate anaemia, thrombocytosis, and a high-sensitivity cardiac troponin of 30 ng/L has a risk of perioperative myocardial infarction/injury of 44.5% (C). PMI, perioperative myocardial infarction/injury; BMI, body mass index; CAD, coronary artery disease; MI, myocardial infarction; MET, metabolic equivalent of task; ESC, European Society of Cardiology; WHO, World Health Organization.

Figure 4

Recalibration cohort. Comparison of Model 3 with the revised cardiac risk index and the American Society of Anesthesiologists classification for the prediction of perioperative myocardial infarction/injury in the recalibration cohort (A). Comparison of the area under the receiver operating characteristic curve of the three prediction models to perioperative myocardial infarction/injury in the recalibration cohort (B). RCRI, revised cardiac risk index; ASA, American Society of Anesthesiologists; PMI, perioperative myocardial infarction/injury; AUC, area under the receiver operating characteristic curve.