Absolute Postoperative B-Type Natriuretic Peptide Concentrations, but Not Their General Trend, Are Associated With 12-Month, All-Cause Mortality After On-Pump Cardiac Surgery

Prediction of acute kidney injury after cardiac surgery from preoperative N-terminal pro-B-type natriuretic peptide

BACKGROUND

Acute kidney injury (AKI) is common after cardiac surgery and is difficult to predict. N-terminal pro-B-type natriuretic peptide (NT-proBNP) is highly predictive for perioperative cardiovascular complications and may also predict renal injury. We therefore tested the hypothesis that preoperative NT-proBNP concentration is associated with renal injury after major cardiac surgery.

METHODS

We included 35 337 patients who had cardiac surgery and measurements of preoperative NT-proBNP and postoperative creatinine. The primary outcome was Kidney Disease: Improving Global Outcomes Stages 1-3 AKI. We also separately considered severe AKI, including Stage 2, Stage 3, and new-onset dialysis.

RESULTS

Postoperative AKI occurred in 11 999 (34.0%) patients. Stage 2 AKI occurred in 1200 (3.4%) patients, Stage 3 AKI in 474 (1.3%) patients, and new-onset dialysis was required in 241 (0.7%) patients. The NT-proBNP concentrations (considered continuously or in quartiles) were significantly correlated with any-stage AKI and severe AKI (all adjusted P<0.01). Including NT-proBNP significantly improved AKI prediction (net reclassification improvement: 0.24 [0.22-0.27]; P<0.001) beyond basic models derived from other baseline factors in the overall population. Reclassification was especially improved for higher grades of renal injury: 0.30 (0.25-0.36) for Stage 2, 0.46 (0.37-0.55) for Stage 3, and 0.47 (0.35-0.60) for dialysis.

CONCLUSIONS

Increased preoperative NT-proBNP concentrations were associated with postoperative AKI in patients having cardiac surgery. Including NT-proBNP substantially improves AKI predictions based on other preoperative factors.

Utility of NT-proBNP as an objective marker of postoperative heart failure after coronary artery bypass surgery: a prospective observational study

Background

Postoperative heart failure (PHF) is the main cause for mortality after cardiac surgery but unbiased evaluation of PHF is difficult. We investigated the utility of postoperative NT-proBNP as an objective marker of PHF after coronary artery bypass surgery (CABG).

Methods

Prospective study on 382 patients undergoing isolated CABG for acute coronary syndrome. NT-proBNP was measured preoperatively, the first (POD1) and third postoperative morning (POD3). A blinded Endpoints Committee used prespecified criteria for PHF. Use of circulatory support was scrutinized.

Results

After adjusting for confounders PHF was associated with 1.46 times higher NT-proBNP on POD1 (p = 0.002), 1.54 times higher on POD3 (p < 0.0001). In severe PHF, NT-proBNP was 2.18 times higher on POD1 (p = 0.001) and 1.81 times higher on POD3 (p = 0.019). Postoperative change of NT-proBNP was independently associated with PHF (OR 5.12, 95% CI 1.86–14.10, p = 0.002). The use of inotropes and ICU resources increased with incremental quartiles of postoperative NT-proBNP.

Conclusions

Postoperative NT-proBNP can serve as an objective marker of the severity of postoperative myocardial dysfunction. Due to overlap in individuals, NT-proBNP is useful mainly for comparisons at cohort level. As such, it provides a tool for study purposes when an unbiased assessment of prevention or treatment of PHF is desirable.

Trial registration

ClinicalTrials.gov Identifier: NCT00489827https://clinicaltrials.gov/ct2/show/NCT00489827?term=glutamics&draw=2&rank=1.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13741-021-00194-4.

Postoperative Cardiac Troponin I Thresholds Associated With 1-Year Cardiac Mortality After Adult Cardiac Surgery: An Attempt to Link Risk Stratification With Management Stratification in an Observational Study

OBJECTIVES

Cardiac troponin (cTn) concentrations are measured routinely in some centers after cardiac surgery as part of risk stratification, but there are no data on how increased cTn concentrations could change patients' management. The aim of this study was to estimate relevant cTnI thresholds and identify potential interventions (additional monitoring/therapeutic interventions) that could be part of management changes of patients with cTnI greater than relevant thresholds.

DESIGN

Retrospective, single-center, observational study.

SETTING

Bichat-Claude Bernard Hospital, Paris, France, between January 1, 2009, and December 31, 2012.

PARTICIPANTS

Consecutive adult patients undergoing cardiac surgery.

MEASUREMENTS AND MAIN RESULTS

cTnI was measured on the 20th postoperative hour. Causes of death and possible interventions were determined by analysis of individual medical records. cTnI thresholds for 1-year cardiac mortality with a specificity >80% were calculated. For this study, 3,228 procedures were analyzed; 129 deaths occurred (4%), 83 of which (2.6%) were cardiac deaths. Threshold cTnI values were 4.2 µg/L for coronary artery bypass grafting (95% confidence interval [CI] 3.9-4.5) and 10.7 µg/L for non-coronary artery bypass grafting (95% CI 10.0-11.3). In multivariable analysis, the EuroSCORE II (odds ratio 1.1 [95% CI 1.06-1.13]; p < 0.001) and cTnI concentrations greater than the thresholds (odds ratio 5.62 [95% CI 3.37-9.37]; p < 0.001) were associated with significantly increased risk of death. The additive and absolute Net Reclassification Index were 0.288% and 14.1%, respectively, for a logistic model including cTnI and EuroSCORE II (area under the curve C-index 0.82 [95% CI 0.77-0.87]) compared with a model including only EuroSCORE II (area under the curve C-index 0.80 [95% CI 0.75-0.84]). Fifty-three of the 83 patients who experienced cardiac death (64%) had a cTnI concentration greater than the threshold, and an intervention was deemed possible in 47 of those 53 (89%) (mostly patients with mild postoperative cardiac dysfunction). For noncardiac deaths, 28% of patients had a cTnI concentration greater than the threshold and no interventions were deemed possible.

CONCLUSIONS

In an attempt to evolve from risk to management stratification, this study's results identified a subgroup of patients with mild cardiac dysfunction and a cTnI concentration greater than the threshold who could be the target for interventions in future validation studies concerning changes in patient management.

Natriuretic Peptides in Cardiac Anesthesia and Intensive Care

Natriuretic peptides, predominantly B-type, are widely used in cardiology as prognostic and diagnostic biomarkers or, much less often, as a substantive treatment tool. They are hormones that are produced mainly in the myocardium in response to overload and ischemia, and their level quite accurately reflects the degree of myocardial dysfunction. Although their use in cardiac anesthesia and intensive care setting seems to be very beneficial for assessing the risk of acute disturbance of myocardial function or its laboratory monitoring, the actual significance of natriuretic peptides in this area is not yet recognized. This is due to the lack of clear diagnostic and prognostic values for these biomarkers supported by high-quality researches. On the basis of the available data, main advantages, existing difficulties, and most effective ways of using natriuretic peptides for determining the risk of heart surgery and assessing the severity of sepsis, pneumonia, and other critical conditions have been discussed in this review. In addition, the expediency of using natriuretic peptides as target parameters for goal-oriented therapy and as a substantive tool for treatment is considered.