The added value of different biomarkers to the Revised Cardiac Risk Index to predict major adverse cardiac events and all-cause mortality after noncardiac surgery

This is a protocol for a Cochrane Review (Prognosis). The objectives are as follows: The primary objective of this Cochrane Review is to quantify the added predictive value of several biomarkers to the Revised Cardiac Risk Index (RCRI) and to estimate the predictive performance of biomarkers compared to the RCRI alone to predict major adverse cardiac events (MACEs) and all-cause mortality in patients undergoing noncardiac surgery. Table 1 represents the PICOTS of the review based on the CHARMS checklist (Moons 2014). Table 1. PICOTS of the review based on the CHARMS checklist Population targeted Patients undergoing noncardiac surgery Intervention (index model) Prognostic model; Revised Cardiac Risk Index (RCRI) Comparator model Addition of biomarkers to the RCRI or comparison of biomarkers alone to the RCRI Outcome(s) to be predicted Major adverse cardiac events (MACEs) and all-cause mortality Time span of the prediction All time spans Setting (intended role and use of the model) To inform physicians preoperatively of the patient's risk of developing events after noncardiac surgery Investigation of sources of heterogeneity between studies We will assess sources of heterogeneity based on the population, outcome definitions and prediction horizons. The RCRI was originally developed for a noncardiac, nonvascular surgical population to predict in-hospital MACEs. However, the RCRI has also been externally validated in vascular surgical patients (Gillmann 2014; Scrutinio 2014), in which the predictive performance was found to be moderate (Ford 2010). In addition, prediction horizons vary between studies from in-hospital to long-term events (e.g. postoperative 1-year all-cause mortality). Finally, the composition of items that defines MACEs varies among different studies.