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Editorial

Using High-Sensitivity Troponin for Enhancing Risk Prediction after Non-Cardiac Surgery – Are We There Yet?

The homeostatic disruption related to non-cardiac surgery is a well-described trigger for cardiovascular morbidity and mortality in the early and late post-operative periods.^, Through multiple mechanisms, including inflammation and hypercoagulability, hemodynamic instability and blood loss, hypoxemia or suspension of protective therapies, known or silent chronic cardiac conditions like coronary artery disease, left ventricular dysfunction or valve disease may serve as the substrate for myocardial ischemia and infarction, heart failure or arrhythmias.

Epidemiologically, a significant rate of cardiac complications, combined with an immense number of patients undergoing non-cardiac surgical procedures per annum creates a major public healthcare challenge, necessarily shifting the focus towards prevention. Traditionally, risk assessment has been based on patient factors, type of surgery, and urgency of the intervention, which are included, albeit with different weighing, in the available risk scores.^, Unfortunately, the discriminative ability of existing scores is far from optimal, leaving room for complementary tools like biomarkers. Specifically, the bloodstream release of cardiac troponin (cTn), reflecting multifactorial cardiomyocyte injury, has been shown to signal increased morbidity and mortality when elevated in the perioperative period. However, and until now, the integration of this so-called MINS (“myocardial injury after non-cardiac surgery”) with the more familiar clinical risk evaluation in the task of risk prediction remains a question to be properly answered.

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Original Article

Addition of High-Sensitivity Troponin to Perioperative Risk Assessment Improves the Predictive Ability of Death in Non-Cardiac Surgery Patients

Bruno Ferraz de Oliveira Gomes et al. Thiago Moreira Bastos da Silva Giovanni Possamai Dutra Leticia de Sousa Peres … Nathalia Duarte Camisão Walter de Souza Homena Júnior João Luiz Fernandes Petriz Plinio Resende do Carmo Junior Basilio de Bragança Pereira Gláucia Maria Moraes de Oliveira

Abstract

Background

Risk stratification is an important step in perioperative evaluation. However, the main risk scores do not incorporate biomarkers in their set of variables.

Objective

Evaluate the incremental power of troponin to the usual risk stratification

Methods

A total of 2,230 patients admitted to the intensive care unit after non-cardiac surgery were classified according to three types of risk: cardiovascular risk (CVR), Revised Cardiac Risk Index (RCRI); and inherent risk of surgery (IRS). The main outcome was all-cause mortality. Cox regression was used as well as c-statistics before and after addition of high-sensitivity troponin (at least one measurement up to three days after surgery). Finally, net reclassification index and integrated discrimination improvement were used to assess the incremental power of troponin for risk stratification. Significance level was set at 0.05.

Results

Mean age of patients was 63.8 years and 55.6% were women. The prevalence of myocardial injury after non-cardiac surgery (MINS) was 9.4%. High CVR-patients had a higher occurrence of MINS (40.1 x 24.8%, p<0.001), as well as high IRS-patients (21.3 x 13.9%, p=0.004) and those with a RCRI≥3 (3.0 x 0.7%, p=0.009). Patients without MINS, regardless of the assessed risk, had similar mortality rate. The addition of troponin to the risk assessment improved the predictive ability of death at 30 days and at 1 year in all risk assessments.

Conclusion

The prevalence of MINS is higher in the high-risk population. However, its prevalence in lower-risk population is not negligible and causes a higher risk of death. The addition of high-sensitivity troponin increased the predictive ability of risk assessment in all groups.