New horizons: NT-proBNP for risk stratification of patients with shock in the intensive care unit

Cardiac Troponin I but Not N-Terminal Pro-B-Type Natriuretic Peptide Predicts Outcomes in Cardiogenic Shock

This study investigates the prognostic value of cardiac troponin I (cTNI) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels in patients with cardiogenic shock (CS). Data regarding the prognostic value of cardiac biomarkers in CS is scarce, furthermore, most studies were restricted to CS patients with acute myocardial infarction (AMI). Therefore, consecutive patients with CS from 2019 to 2021 were included. Blood samples were retrieved from day of disease onset (day 1) and on days 2, 3 and 4 thereafter. The prognostic value of cTNI and NT-proBNP levels was tested for 30-day all-cause mortality. Statistical analyses included univariable t-tests, Spearman's correlations, Kaplan-Meier analyses and multivariable Cox proportional regression analyses. A total of 217 CS patients were included with an overall rate of all-cause mortality of 56% at 30 days. CTNI was able to discriminate 30-day non-survivors (area under the curve (AUC) = 0.669; p = 0.001), whereas NT-proBNP (AUC = 0.585; p = 0.152) was not. The risk of 30-day all-cause mortality was higher in patients with cTNI levels above the median (70% vs. 43%; log rank p = 0.001; HR = 2.175; 95% CI 1.510-3.132; p = 0.001), which was observed both in patients with (71% vs. 49%; log rank p = 0.012) and without AMI-related CS (69% vs. 40%; log rank p = 0.005). The prognostic impact of cTNI was confirmed after multivariable adjustment (HR = 1.915; 95% CI 1.298-2.824; p = 0.001). In conclusion, cTNI-but not NT-proBNP-levels discriminated 30-day all-cause mortality in CS patients.

What Is High Enough? Elevated NT-pro-BNP in Decompensated Paroxysmal Supraventricular Tachycardia

Since the late 1980s, elevated atrial natriuretic peptide (ANP) was considered the cause of brisk diuresis in adult patients with paroxysmal supraventricular tachycardia (PSVT). Pro-brain natriuretic peptide (pro-BNP) and related molecules, e.g., N-terminal pro b-type natriuretic peptide (NT-pro-BNP) are known biomarkers of heart failure in adult patients from many causes with probable relevance in children. Perhaps, pro-BNP or related molecules such as NT-pro-BNP are useful in the management of PSVT in infants, thus hastening treatment in children who may otherwise significantly decompensate. Case series of one infant and two neonates presenting with cardiogenic shock and evidence of heart failure are presented. Cardiac monitoring or electrocardiogram (ECG) confirmed the presence of PSVT. Adenosine was administered resulting in successful chemical cardioversion with each case. Significantly elevated NT-pro-BNP levels correlated with heart failure prior to cardioversion. In each case, patients were discharged home with lower NT-pro-BNP levels and maintenance with a β-blocker. Due to documented relationships between elevated pro-BNP level and heart failure in adults, the authors measured the related biomarker NT-pro-BNP in each case, as the relationship could be similar in pediatric PSVT. Based on our experience with children in acute heart failure from other causes, NT-pro-BNP can increase to potentially extreme levels in infants. It appears to correlate with clinical signs of insufficient cardiac output, such as tachycardia, respiratory distress, and moribund appearance. Indeed, in the case series, extremely high NT-pro-BNP values were obtained when the patients appeared moribund from decompensated PSVT. The question arising from these observations is: At what level of elevated NT-pro-BNP, would patients be identified for cardioversion prior to appearance of other signs and symptoms? For each patient within the case series, NT-pro-BNP levels of approximately 20,000 pg/mL were indicative of decompensated heart failure, which was subsequently confirmed by examination of the patient. Further investigation is needed to determine the clinical significance of NT-pro-BNP and related peptides in pediatric patients with PSVT and intermittent PSVT. However, the possibility exists that an increase in NT-pro-BNP and related peptides could be a biomarker for cardiac decompensation after prolonged or intermittent PSVT, thereby shortening the time of diagnosis and intervention, and hence, potentially preventing morbidity, mortality, and extended hospitalization. Additional evidence-based research would help provide biomarker information during PSVT allowing practitioners to more objectively analyze risks.

N-terminal pro-brain natriuretic peptide and cardiac troponin I for the prognostic utility in elderly patients with severe sepsis or septic shock in intensive care unit: A retrospective study

BACKGROUNDS

Using biomarkers to predict mortality in patient with severe sepsis or septic shock is of importance, as these patients frequently have high mortality and unsatisfied outcome. N-terminal pro-brain natriuretic peptide (NT-proBNP) and cardiac troponin I (cTnI) play extremely important roles in prognostic value in the mortality of severe sepsis and septic shock.

AIMS

The present study was retrospectively designed to evaluate the predicting mortality of NT-proBNP and cTnI in elderly patients with severe sepsis or septic shock administered in the intensive care unit (ICU) and also to evaluate whether the predicting ability of Acute Physiology and Chronic Health Evaluation II (APACHE-II) score or C-reactive protein (CRP) was increased in combination with the biomarkers.

PATIENTS AND METHODS

A cohort of 430 patients (aged ≥65 years) with severe sepsis or septic shock admitted to our ICU between October 2011 and December 2013 was included in the study. Patient data including clinical, laboratory, and survival and mortality were collected. All patients were examined with NT-proBNP, cTnI, CRP, and APACHE-II score and were categorized as the survived and deceased groups according to the outcome 30 days after ICU treatment.

RESULTS

The levels of NT-proBNP and cTnI (P < .01) or CRP (P < .05) were significantly higher in the deceased group than those in the survived group. The predicting mortality of APACHE-II score alone was low but largely improved, when it was combined with both NT-proBNP and cTnI (P < .05).

CONCLUSION

The alteration of NT-proBNP and cTnI levels strongly predicated the ICU prognosis in elderly patients with severe sepsis or septic shock. N-terminal pro-brain natriuretic peptide and cTnI were superior to CRP in predicting mortality. The predicting ability of APACHE-II score was improved only when combined with NT-proBNP and cTnI.

Uncoordinated regulation of atrial natriuretic factor and brain natriuretic peptide in lipopolysaccharide-treated rats

We investigated the expression and secretion of the natriuretic peptides (NPs) ANF and BNP in lipopolysaccharide (LPS)-induced sepsis and its association with cytokines and other biologically active substances. LPS treatment increased plasma levels of ANF and BNP. The latter increase was larger than the increase in plasma ANF. LPS also increased cardiac content and gene expression of BNP but not of ANF. LPS treatment significantly increased gene expression cytokines, chemokines and proteases, which significantly correlated with BNP gene expression. SB203580, a p38 MAP kinase inhibitor, inhibited the elevation of BNP in plasma. The present work suggests that during inflammation, BNP gene expression and secretion is uniquely related to changes in gene expression in the absence of hemodynamic changes and hence differentiates ANF and BNP as biomarkers of cardiac disease.

B-type natriuretic peptide predicts long-term prognosis in a cohort of critically ill patients

B-type natriuretic peptide is an important prognostic marker in heart failure. However, there are limited data for its value in non-cardiac intensive care unit patients, namely regarding long-term prognosis. We investigated the long-term prognostic value of BNP in a cohort of critically ill patients. This was a prospective and observational study, conducted in a tertiary university hospital 20-bed intensive care unit. We included 103 mechanically-ventilated patients admitted for a non-cardiac primary diagnosis; B-type natriuretic peptide samples were obtained on admission. A mean 14 (3–30) month follow up was available in 96.1% of patients who were discharged from hospital. Mean age was 60.7±19.0 years and mean APACHE II score was 16.2±7.2. APACHE II score and renal dysfunction increased with rising B-type natriuretic peptide, with more than 60% of patients having B-type natriuretic peptide levels of 100 pg/mL or over; echocardiography-derived left ventricular ejection fraction was lower in patients with higher B-type natriuretic peptide (P < 0.001). Long-term survivors had lower median B-type natriuretic peptide values (117.5[2–1668] pg/mL) compared with intensive care unit non-survivors (191.0[5–4945] pg/mL), P<0.001. After adjustment to APACHE II score, B-type natriuretic peptide levels of 300 pg/mL or over were independently associated with long-term mortality (odds-ratio 4.1 [95% CI 1.45–11.5], P=0.008). We conclude that in an unselected cohort of intensive care unit patients, admission B-type natriuretic peptide is frequently elevated, even without clinically apparent acute heart disease, and is a strong independent predictor of long-term mortality.

Circulating high sensitivity troponin T in severe sepsis and septic shock: distribution, associated factors, and relation to outcome

PURPOSE

To assess the clinical utility of a recently developed highly sensitive cardiac troponin T (hs-cTnT) assay for providing prognostic information on patients with sepsis.

METHODS

cTnT levels were measured by the novel hs-cTnT assay at two time points (inclusion and 72 h thereafter) in a subgroup of patients from the FINNSEPSIS study and associations with clinical outcomes were examined. Results for the hs-cTnT assay were compared to those of the established fourth-generation cTnT assay.

RESULTS

cTnT measured by the fourth-generation and hs-cTnT assay was detectable in 124 (60%) and 207 (100%) patients, respectively, on inclusion in this study. hs-cTnT levels on inclusion correlated with several indices of risk in sepsis, including the simplified acute physiology score (SAPS) II and sequential organ failure assessment (SOFA) scores. The level of hs-cTnT on inclusion was higher in hospital non-survivors (n = 47) than survivors (n = 160) (median 0.054 [Q1-3, 0.022-0.227] versus 0.035 [0.015-0.111] μg/L, P = 0.047), but hs-cTnT level was not an independent predictor of in-hospital mortality. hs-cTnT levels on inclusion were also higher in patients with septic shock during the hospitalization (0.044 [0.024-0.171] versus 0.033 [0.012-0.103] μg/L, P = 0.03), while this was not the case for the fourth-generation cTnT assay or NT-proBNP levels.

CONCLUSIONS

Circulating hs-cTnT is present in patients with severe sepsis and septic shock, associates with disease severity and survival, but does not add to SAPS II score for prediction of mortality. hs-cTnT measurement could still have a role in sepsis as an early marker of shock.

What is the value of B-type natriuretic peptide testing for diagnosis, prognosis or monitoring of critically ill adult patients in intensive care?

BACKGROUND

B-natriuretic peptide (BNP) and aminoterminal proBNP (NT-proBNP) are clinically useful for the diagnosis of decompensated heart failure and for prognosis in heart failure and acute coronary syndromes. Clinical use of these biomarkers in critically ill patients being treated in intensive care is not well established.

METHODS

This is a narrative review of evidence identified searching MEDLINE with the strategy [(BNP OR NT-proBNP) AND (critical illness AND intensive care)]. Seven primary reports and two narrative reviews were retrieved. For completeness, literature from each of the following searches was reviewed: [(BNP OR NT-proBNP) AND (critical illness)] and [(BNP OR NT-proBNP) AND (intensive care)].

RESULTS

Primary literature used BNP and NT-proBNP for diagnosis, prognosis and monitoring. For diagnosis of acute lung injury in unselected intensive care patients and for diagnosis of heart failure in trauma patients, the biomarkers had low sensitivity and are of modest use. BNP and NT-proBNP were found to have a significant ability to prognosticate adverse outcomes in critically ill patients. A single paper examined the use of BNP as a non-invasive replacement for pulmonary capillary wedge pressure, finding little value. The impact of renal insufficiency on the markers was noted as a confounder in most studies. In the secondary searches, some preliminary data suggested a possible role for the natriuretic peptides in exclusion of a cardiac cause for certain conditions among intensive care unit (ICU) patients. However, the general findings were that the performance of BNP and NT-proBNP is unimpressive among ICU patients.

CONCLUSIONS

Currently, utilization of BNP and NT-proBNP does not appear to provide much useful information or have a substantial role in the care of critically ill patients in intensive care.

Interpretation of B-type natriuretic peptide in cardiac disease and other comorbid conditions

B-Type natriuretic peptide (BNP) is elevated in states of increased ventricular wall stress. BNP is most commonly used to rule out congestive heart failure (CHF) in dyspneic patients. BNP levels are influenced by age, gender and, to a surprisingly large extent, by body mass index (BMI). In addition, it can be elevated in a wide variety of clinical settings with or without CHF. BNP is elevated in other cardiac disease states such as the acute coronary syndromes, diastolic dysfunction, atrial fibrillation (AF), amyloidosis, restrictive cardiomyopathy (RCM), and valvular heart disease. BNP is elevated in non-cardiac diseases such as pulmonary hypertension, chronic obstructive pulmonary disease, pulmonary embolism, and renal failure. BNP is also elevated in the setting of critical illness such as in acute decompensated CHF (ADHF) and sepsis. This variation across clinical settings has significant implications given the increasing frequency with which BNP testing is being performed. It is important for clinicians to understand how to appropriately interpret BNP in light of the comorbidities of individual patients to maximize its clinical utility. We will review the molecular biology and physiology of natriuretic peptides as well as the relevant literature on the utilization of BNP in CHF as well as in other important clinical situations, conditions that are commonly associated with CHF and or dyspnea.