B-type natriuretic peptide-guided therapy for perioperative medicine?

The utility of brain natriuretic peptide as a prognosticating marker in critical care patients

Background

Brain natriuretic peptide (BNP) is an established biomarker of morbidity and mortality in cardiac failure. Data also suggest potential prognostic utility in non-heart failure cohorts. The utility of BNP in predicting intensive care unit (ICU) outcomes has not been well evaluated in a mixed critical care population in the South African (SA) context.

Objectives

To evaluate the ability of BNP to predict ICU mortality in a heterogeneous critical care population in SA.

Methods

This was a retrospective observational study of 100 patients admitted to a multidisciplinary, closed, intensivist-run ICU in a tertiary academic hospital serving KwaZulu-Natal Province (1 January 2020 - 31 July 2022). Initial BNP was evaluated as a predictor of ICU mortality using univariate and multivariable analyses.

Results

There was a statistically significant difference in BNP between survivors and non-survivors in the cohort of patients without heart failure. The median initial BNP in the non-heart failure cohort was 411 (interquartile range (IQR) 116 - 848) ng/L in non-survivors, and 150 (44 - 356) ng/L in survivors (p=0.028). The optimal cut-off for BNP was determined as 366 ng/L. A BNP ≥366 ng/L was an independent predictor of ICU outcome.

Conclusion

This study highlights the potential utility of BNP as a predictor of ICU mortality in a heterogeneous ICU population, with the greatest utility in patients without heart failure. Further studies are required to confirm this finding.

Contribution of the study

The study is a retrospective, observational study conducted in multidisciplinary, closed, intensivist-run ICU at a tertiary academic hospital. It showed an elevated BNP is associated with increased ICU mortality, particularly in those without a baseline diagnosis of heart failure. This identifies the need for further prospective studies evaluating BNP as a prognostic marker in non-cardiac critically ill patients, and its utility as an addition in pre-existing ICU outcome prediction scores.

The frequency of postoperative BNP measurement and intervention threshold of BNP concentration in pediatric cardiac intensive care unit: a prospective multicenter observational study

PURPOSE

The purpose of this study is to investigate the current status of postoperative BNP measurement in the pediatric cardiac intensive care unit (PCICU).

METHODS

This was a prospective multicenter observational study. Children under 15 years old who underwent pediatric cardiac surgery were included. Postoperatively, all BNP measurement was collected in PCICU. We checked whether each BNP measurement was used for the decision-making of intervention or not. We divided the BNP measurements into 4 groups: group A 0-299 pg/ml (reference), group B 300-999 pg/ml, group C 1000-1999 pg/ml, group D ≧ 2000 pg/ml. We performed logistic regression analysis to compare the intervention ratio between group A and B, C, D. We also did multiple comparison analyses to compare the intervention ratio in each group.

RESULTS

Thirty-nine (15.8%) measurements were used as a criterion to intervene in all BNP measurements. There was no protocol for the measurement of BNP in all institutions. The number of BNP measurements in each group is as follows: group A 113 (45.9%), group B 81 (32.9%), group C 45 (18.3%), group D 7 (2.8%). The intervention ratio in each group was 6.2% (group A), 8.6% (group B), 44.4% (group C), and 71.4% (group D). The intervention ratio of group C and D were significantly higher than group A: (Odds ratio (95%CI): 12.1(4.8-33.9), p < 0.0001, 25.2(5.2-146.2), p < 0.0001). The result of multiple comparisons is similar to logistic regression analysis.

CONCLUSION

High BNP concentration, especially more than 1000 pg/ml, was more often intervened upon compared to that of less than 1000 pg/ml.

Prognostic Value of Preoperative Pro-B-Type Natriuretic Peptide: Early Predictor of Cardiovascular Complications and Mortality After Major Abdominal Surgery

Background and objectives

In surgical patients, coronary disease is the main cause of perioperative mortality. The incidence of serious cardiovascular complications is reported as 5% with a probability of 1-2% of death from the cardiac cause in major non-cardiac surgery. B-type natriuretic peptide (BNP) is a sensitive and specific predictor of left ventricular systolic dysfunction and predicts first cardiovascular event and death in the general population. The recent guidelines recommended the use of pro-BNP for independent perioperative prognosis in cardiac patients undergoing non-cardiac surgery. The aim of this study is to assess the predictive value of raised pro-BNP levels in patients who underwent major abdominal surgery and evaluate its relationship with cardiovascular complications and mortality occurring up to 30 days after surgery.

Materials and methods

We reviewed the medical records of patients undergone surgical procedures in the abdominal region lasting more than two hours, requiring postoperative high dependence or intensive care and an expected hospital stay of at least three days. All types of open or laparoscopic-assisted abdominal or pelvic surgeries that were evaluated for preoperative pro-BNP levels were included in the study. During the postoperative period, all patients were followed for cardiac complications and mortality for 30 days after surgery. Postoperative adverse cardiac events were predefined as angina pectoris, myocardial infarction, cardiogenic dyspnea, acute arrhythmias (atrial fibrillation/flutter, ventricular fibrillation/tachycardia), acute hypertensive event (hypertensive emergency or urgency), congestive heart failure, acute pulmonary edema, or primary cardiac death. While non-cardiac complications were also documented as either pulmonary, septic, postsurgical site infection, and other systemic complications. Subsequently, a survival analysis was done for the discretion of cardiovascular complications and mortality.

Results

The mean age of the study population was found to be 50.22 ± 14.28 years, mean pro-BNP levels were 909.29 ± 3950.04, and mean days of hospital stay were 7.43 ± 4.49 days. The 30-day postoperative all-cause mortality was found to be 9.8%. Hypertension and diabetes were frequent comorbidities amongst the study population. The mean preoperative pro-BNP levels were found higher in the male gender (p=0.071), also found higher in those with cardiovascular complications (p=0.006) and mortality (p=0.057). Receiver operating characteristic (ROC) analysis showed cardiovascular outcomes with a cut-off value of pro-BNP at 143 pg/ml, AUC of 0.891, at a sensitivity of 91%, positive predictive value (PPV) of 96%, a specificity of 75%, and negative predictive value (NPV) of 58%, while the same for mortality at a cut-off value of 164 pg/ml was found with AUC of 0.815, at a sensitivity of 84%, a specificity of 66%, PPV of 97%, and NPV of 21%. The unadjusted odds ratio for cardiovascular complications was found to be 17.857 (95% CI: 6.56-48.60) while that for mortality was 10.863 (95% Cl: 2.29-51.37). The Kaplan-Meier survival curves showing elevated pro-BNP levels were significantly associated with cardiovascular events, with 30 days mortality at a cut-off value of 164 pg/ml.

Conclusion

Pro-BNP is a useful marker in postoperative patients for not only predicting cardiovascular outcomes as cited by many previous studies but also mortality.

Cardiovascular Risk Assessment for Noncardiac Surgery: Are We Ready for Biomarkers?

Biomarkers aided perioperative cardiac assessment is a relatively new concept. Cardiac biomarkers with historical significance (aspartate transaminase, dehydrogenase, creatinine kinase and myoglobin) have paved the way for traditional biomarkers (cardiac troponin, C-reactive protein, lipoprotein). Contemporary biomarkers like natriuretic peptides (BNP and ProBNP) are validated risk markers in both acute and chronic cardiac diseases and are showing remarkable promise in predicting serious cardiovascular complications after non-cardiac surgery. This review is intended to provide a critical overview of traditional and contemporary biomarkers for perioperative cardiovascular assessment and management. This review also discusses the potential utility of newer biomarkers like galectin-3, sST-2, GDF-15, TNF-alpha, MiRNAs and many others that can predict inflammation, cardiac remodeling, injury and endogenous stress and need further investigations to establish their clinical utility. Though promising, biomarker led perioperative care is still in infancy and it has not been determined that it can improve clinical outcomes.