High circulating N-terminal pro-B-type natriuretic peptide is associated with greater systolic cardiac dysfunction and nonresponsiveness to fluids in septic vs nonseptic critically ill patients

[Natriuretic peptides in intensive care medicine]

Natriuretic peptides must be interpreted in their clinical context, especially in intensive care medicine. This overview presents the diagnostic, prognostic, and therapeutic significance of B‑type natriuretic peptide (BNP) and N‑terminal pro B‑type natriuretic peptide (NT-proBNP) in patients with cardiac dysfunction, kidney failure, sepsis, pulmonary embolism, acute respiratory distress syndrome (ARDS), acute exacerbations of chronic obstructive pulmonary disease (AECOPD), and weaning from a respirator.

N-Terminal B Natriuretic Peptide as a Prognostic Marker in Sepsis Induced Myocardial Dysfunction

BACKGROUND: Sepsis-induced myocardial dysfunction (SIMD) is an increasingly recognized form of transient cardiac dysfunction in sepsis patients. AIM: The aim of the study was to evaluation of N-terminal pro brain natriuretic peptide (NT-pro BNP) as a predictor of SIMD and poor outcome in patients with sepsis or septic shock. METHODS: Forty patients were enrolled and divided into: Group 1 with sepsis; Group 2 with septic shock. Each group was subdivided according to the presence or absence of cardiomyopathy. Echocardiography, NT-pro BNP - assay on the 1st and 2nd days of admission - were performed. RESULTS: NT-pro BNP level was significant predictor for cardiomyopathy in all case group with 75% sensitivity, 70% specificity (cutoff level >334 pg/ml) on 1st day of admission and 65% sensitivity, and 80% specificity (cutoff level >325 pg/ml) on 2nd day. On subgroup analysis, pro-BNP had 70% sensitivity, 90% specificity; cutoff level >334 pg/ml for prediction of cardiomyopathy in sepsis group and 70% sensitivity and 80% specificity; cutoff level >357pg/ml in septic shock group. Pro-BNP on 2nd day was excellent predictor of mortality in septic shock group with 100% sensitivity and specificity; cutoff level >350 pg/ml. CONCLUSION: N terminal pro-BNP is a good diagnostic and prognostic indicator for cardiomyopathy and mortality in septic patients.

Altered function of the left ventricle and clinical significance of heart-type fatty acid-binding protein in cardiac dysfunction among patients with sepsis

The present study aimed to determine the clinical significance of heart-type fatty acid-binding protein (H-FABP) in patients with sepsis-induced cardiac dysfunction. A total of 30 healthy subjects served as the control group and 80 patients with sepsis were recruited for the present single-center prospective observational study for the final analysis. Among these patients, 50 developed cardiac dysfunction, while no cardiac dysfunction was detected in the remaining 30 patients. Echocardiography was performed on days 1, 3, 7 and 10 of hospitalization. Routine blood biochemistry, serum H-FABP, N-terminal pro-brain natriuretic peptide (NT-proBNP) and troponin I were also analyzed. Alterations in cardiac biomarkers and echocardiography results were compared between patients with sepsis who did and who did not develop any cardiac dysfunction to determine the time of the occurrence of sepsis-induced cardiac dysfunction. Furthermore, the significance of H-FABP in the prediction of the 28-day mortality rate was evaluated using binary logistic regression analysis for sepsis and receiver operating characteristic (ROC) curve analysis. In addition, the specificity and sensitivity of H-FABP in the prediction of sepsis-induced cardiac dysfunction were verified using ROC curve analysis. For patients with cardiac dysfunction, the levels of cardiac output (CO), stroke volume (SV), mitral early diastolic peak velocity to mitral atrial systolic peak velocity ratio (E/A) and left ventricle ejection fraction (LVEF) were relatively decreased, while the levels of H-FABP and NT-proBNP were markedly increased compared with patients with sepsis and without cardiac dysfunction. CO and SV initially increased and subsequently decreased. EF was elevated, and E/A initially decreased and subsequently increased. Furthermore, H-FABP and NT-proBNP decreased in sepsis patients with cardiac dysfunction. The results of the ROC curve and binary logistic regression analyses suggest that H-FABP was associated with the 28-day prognosis for patients with sepsis. An H-FABP level of >35.7 ng/ml was able to predict the 28-day mortality for patients with sepsis, with an area under the curve (AUC) of 0.680. Furthermore, >30.3 ng/ml was the threshold for the prediction of sepsis-induced cardiac dysfunction, and the sensitivity and specificity were 76.27 and 61.76%, respectively, with an AUC of 0.673. In summary, patients with sepsis had an increased risk of cardiac insufficiency on days 7-10 of hospitalization. In addition, H-FABP may serve as an indicator to predict the prognosis of patients with sepsis in the short term, which has a certain significance in the diagnosis of sepsis-induced cardiac dysfunction.

The role of natriuretic peptides in the management, outcomes and prognosis of sepsis and septic shock

Sepsis continues to be a leading public health burden in the United States and worldwide. With the increasing use of advanced laboratory technology, there is a renewed interest in the use of biomarkers in sepsis to aid in more precise and targeted decision-making. Natriuretic peptides have been increasingly recognized to play a role outside of heart failure. They are commonly elevated among critically ill patients in the setting of cardiopulmonary dysfunction and may play a role in identifying patients with sepsis and septic shock. There are limited data on the role of these biomarkers in the diagnosis, management, outcomes and prognosis of septic patients. This review seeks to describe the role of natriuretic peptides in fluid resuscitation, diagnosis of ventricular dysfunction and outcomes and the prognosis of patients with sepsis. B-type natriuretic peptide (BNP) and N-terminal pro-BNP (NT-proBNP) have been noted to be associated with left ventricular systolic and diastolic and right ventricular dysfunction in patients with septic cardiomyopathy. BNP/NT-proBNP may predict fluid responsiveness, and trends of these peptides may play a role in fluid resuscitation. Despite suggestions of a correlation with mortality, the role of BNP in mortality outcomes and prognosis during sepsis needs further evaluation.

N-terminal pro-B-type natriuretic peptide for predicting fluid challenge in patients with septic shock

Background

The aim of this study is to examine whether plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentration could predict fluid responsiveness in septic shock patients following fluid challenge (FC).

Methods

We reviewed prospectively collected data from 79 septic shock patients who received invasive cardiac output (CO) monitoring following a 500 mL FC. Haemodynamics were recorded, and blood sampling for NT-proBNP values was performed. Patients were divided into responders and non-responders according to fluid responsiveness, which was defined as cardiac index (CI) increase ≥10% induced by FC. The NT-proBNP and the CI changes were analysed using Pearson correlation. The area under the curve (AUC) for NT-proBNP was used to test its ability to distinguish responders and non-responders. Subgroup analyses were also explored.

Results

Among 79 patients, there were 55 responders. High NT-proBNP values were common in the study cohort. Baseline NT-proBNP values were comparable between responders and non-responders. In general, NT-proBNP values were not significantly correlated with CI changes after FC (r=-0.104, P=0.361). Similarly, the NT-proBNP baseline values could not identify responders to FC with an AUC of 0.508 (95% confidence interval, 0.369-0.647). This result was further confirmed in the subgroup analyses.

Conclusions

Baseline NT-proBNP concentration value may not serve as an indicator of fluid responsiveness in patients with septic shock and should not be an indicator to withhold fluid loading.

Association of Heart Rate with N-Terminal Pro-B-Type Natriuretic Peptide in Septic Patients: A Prospective Observational Cohort Study

BACKGROUND

Excessive sympathetic stress has multiple adverse effects during critical illness including sepsis. Recent studies showed that heart rate control had a significant effect on reducing mortality in septic shock patients. Furthermore, elevated N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels in septic patients were reportedly associated with adverse outcome. However, no study has evaluated the relationship between hemodynamic profiles of septic patients and the circulating cardiac biomarker. Our objective was to determine whether hemodynamic profiles, specifically tachycardia and new-onset atrial fibrillation (AF), were associated with NT-proBNP elevation in septic patients.

METHODS

We consecutively enrolled patients admitted to our intensive care unit (ICU). NT-proBNP levels, heart rate, and rhythm at ICU admission were measured, and all clinical and laboratory data were prospectively collected. Tachycardia was defined as a heart rate of above 100 bpm.

RESULTS

Ninety-five patients out of 267 patients (35.6%) were diagnosed as sepsis. Of these septic patients, 47 presented with tachycardia and 6 developed new-onset AF. Multivariate Cox regression analysis revealed that tachycardia was an independent predictor of 28-day overall survival in septic patients (hazard ratio, 4.22; 95% confidence interval, 1.10-27.72; P < 0.05), but not in nonseptic patients. Multivariate linear regression analysis demonstrated that the presence of tachycardia was an independent determinant of NT-proBNP elevation (P < 0.05) in septic patients, but not in nonseptic patients.

CONCLUSIONS

Tachycardia was significantly and independently associated with NT-proBNP elevation and lower survival rate in septic patients, although no association was observed in nonseptic patients. Increased NT-proBNP in sepsis with tachycardia might predict poor outcomes in ICU.

Cardiopulmonary involvement in Puumala hantavirus infection

BACKGROUND

Hantavirus infections cause potentially life-threatening disease in humans world-wide. Infections with American hantaviruses may lead to hantavirus pulmonary syndrome characterised by severe cardiopulmonary distress with high mortality. Pulmonary involvement in European Puumala hantavirus (PUUV) infection has been reported, whereas knowledge of potential cardiac manifestations is limited. We aimed to comprehensively investigate cardiopulmonary involvement in patients with PUUV-infection.

METHODS

Twenty-seven hospitalised patients with PUUV-infection were examined with lung function tests, chest high-resolution CT (HRCT), echocardiography including speckle tracking strain rate analysis, ECG and measurements of cardiac biomarkers N-terminal pro-B-type natriuretic peptide (NT-ProBNP) and troponin T. Patients were re-evaluated after 3 months. Twenty-five age and sex-matched volunteers acted as controls for echocardiography data.

RESULTS

Two-thirds of the patients experienced respiratory symptoms as dry cough or dyspnoea. Gas diffusing capacity was impaired in most patients, significantly improving at follow-up but still subnormal in 38%. HRCT showed thoracic effusions or pulmonary oedema in 46% of the patients. Compared to controls, the main echocardiographic findings in patients during the acute phase were significantly higher pulmonary vascular resistance, higher systolic pulmonary artery pressure, lower left ventricular ejection fraction and impaired left atrial myocardial motion. Pathological ECG, atrial fibrillation or T-wave changes, was demonstrated in 26% of patients. NT-ProBNP concentrations were markedly increased and were inversely associated with gas diffusing capacity but positively correlated to pulmonary vascular resistance. Furthermore, patients experiencing impaired general condition at follow-up had significantly lower gas diffusing capacity and higher pulmonary vascular resistance, compared to those feeling fully recovered.

CONCLUSIONS

In a majority of patients with PUUV-infection, both cardiac and pulmonary involvement was demonstrated with implications on patients' recovery. The results demonstrate vascular leakage in the lungs that most likely is responsible for impaired gas diffusing capacity and increased pulmonary vascular resistance with secondary pulmonary hypertension and right heart distress. Interestingly, NT-ProBNP was markedly elevated even in the absence of overt ventricular heart failure. The method of simultaneous investigations of important cardiac and respiratory measurements improves the interpretation of the underlying pathophysiologic mechanisms.

Clinical utility of natriuretic peptides in left ventricular failure

Left ventricular failure (LVF) is a clinical syndrome caused by abnormal systolic or diastolic function failing to meet the metabolic requirements of the body. It is important to diagnose and manage LVF in the earliest stages to prevent mortality and morbidity. This article extensively reviews the diagnostic, therapeutic, and prognostic utility of natriuretic peptides in LVF.

Sepsis-induced cardiomyopathy

Myocardial dysfunction is one of the main predictors of poor outcome in septic patients, with mortality rates next to 70%. During the sepsis-induced myocardial dysfunction, both ventricles can dilate and diminish its ejection fraction, having less response to fluid resuscitation and catecholamines, but typically is assumed to be reversible within 7-10 days. In the last 30 years, It´s being subject of substantial research; however no explanation of its etiopathogenesis or effective treatment have been proved yet. The aim of this manuscript is to review on the most relevant aspects of the sepsis-induced myocardial dysfunction, discuss its clinical presentation, pathophysiology, etiopathogenesis, diagnostic tools and therapeutic strategies proposed in recent years.

Plasma Brain Natriuretic Peptide and Troponin Levels in Severe Sepsis and Septic Shock

The aim of this study was to evaluate and compare brain natriuretic peptide (BNP) and cardiac troponin I (cTnI) levels as mortality prognosticator and predictor for myocardial dysfunction in severe sepsis and septic shock. Baseline clinical and biological variables were collected from 47 patients with severe sepsis or septic shock. Ventricular systolic function assessed by echocardiography was measured over a 5-day period. Both cTnI and BNP plasmatic levels were determined at intensive care unit (ICU) admission and during the following 15 days. At admission, cTnI and BNP levels were compared to those of 12 control critically ill nonseptic patients. The plasma levels of BNP and cTnI in patients with sepsis were elevated at admission and significantly higher than in the controls. Among patients with sepsis, BNP levels were significantly more elevated in nonsurvivors compared to survivors at admission and 1 day later. The cTnI levels were also significantly more elevated in nonsurvivors compared to survivors, but only at admission. From admission to day 5, patients with sepsis with left ventricular systolic dysfunction had higher BNP plasmatic concentrations than those without; differences were significant at days 3 and 4. In contrast, plasma cTnI levels were similar between the 2 groups. In critically ill patients, sepsis induces significant increase in BNP and cTnI levels. High BNP and cTnI plasma levels during ICU admission appear to be associated with poor outcome of sepsis. Time course of BNP levels seems helpful to discriminate between surviving and nonsurviving patients with sepsis and to detect myocardial dysfunction where troponin levels fail to do so.

Brain natriuretic Peptide production and secretion in inflammation

Gene expression and secretion of the cardiac polypeptide hormones atrial natriuretic factor (ANF) and brain natriuretic peptide (BNP) are simultaneously upregulated in various cardiac disorders such as congestive heart failure, ischemic heart disease, and hypertensive heart disease, in which hemodynamic or neuroendocrine changes are key components in the progression of disease. However, during acute cardiac allograft rejection, plasma BNP levels are increased but not those of ANF. Successful treatment of the rejection episode decreases the elevated plasma BNP to prerejection values suggesting that substances related to inflammation may selectively influence BNP gene expression. Indeed, cytokines such as TNFα and IL-1β selectively stimulate cardiac BNP at the transcriptional and translational levels in cardiomyocyte cultures without affecting ANF. This selective BNP increase is seen in vivo, in addition to acute cardiac allograft rejection, in several circumstances where inflammation significantly contributes to the pathogenesis of disease such as in sepsis and in acute myocarditis.

Predictors of survival in sepsis: what is the best inflammatory marker to measure?

PURPOSE OF REVIEW

Sepsis is relevant due to its high morbidity and mortality. For both sepsis diagnosis and outcome prediction many biomarkers have been described in the literature. Most of these markers are objects of scientific interest rather than being introduced into daily clinical practice. However, due to their unspecific character and their insufficient predictive value for the individual person, research focus is still on new aspects in sepsis-related biomarkers.

RECENT FINDINGS

Beyond the widely used acute-phase proteins C-reactive protein (CRP) and procalcitonin (PCT), many new molecules have been studied deriving from different organs or cells affected, due to the systemic nature of sepsis. Cytokines, coagulation factors/characteristics, vasoactive hormones, and several others have been recently proved to be relevant in sepsis syndrome and probably useful for outcome prediction. However, single time point measurements may be less predictive than consideration of the time-dependent course of parameters. Clinical decision just based on a biomarker is still not feasible because of the huge inter-individual differences in the inflammatory response.

SUMMARY

Many biomarkers display relevant correlation with the clinical outcome of patients with severe sepsis and septic shock. Consideration of their time courses may be more reliable than absolute levels. Clinical decision should not be based only on biomarkers but organ dysfunctions, for example, should also be taken into account.

Relationship between thyroid function and ICU mortality: a prospective observation study

Introduction

Although nonthyroidal illness syndrome is considered to be associated with adverse outcome in ICU patients, the performance of thyroid hormone levels in predicting clinical outcome in ICU patients is unimpressive. This study was conducted to assess the prognostic value of the complete thyroid indicators (free triiodothyronine (FT3), total triiodothyronine; free thyroxine, total thyroxine, thyroid-stimulating hormone and reverse triiodothyronine) in unselected ICU patients.

Methods

A total of 480 consecutive patients without known thyroid diseases were screened for eligibility and followed up during their ICU stay. We collected each patient's baseline characteristics, including the Acute Physiology and Chronic Health Evaluation II (APACHE II) score and thyroid hormone, N-terminal pro-brain natriuretic peptide (NT-proBNP) and C-reactive protein (CRP) levels. The primary outcome was ICU mortality. Potential predictors were analyzed for possible association with outcomes. We also evaluated the ability of thyroid hormones together with APACHE II score to predict ICU mortality by calculation of net reclassification improvement (NRI) and integrated discrimination improvement (IDI) indices.

Results

Among the thyroid hormone indicators, FT3 had the greatest power to predict ICU mortality, as suggested by the largest area under the curve (AUC) of 0.762 ± 0.028. The AUC for FT3 level was less than that for APACHE II score (0.829 ± 0.022) but greater than that for NT-proBNP level (0.724 ± 0.030) or CRP level (0.689 ± 0.030). Multiple regression analysis revealed that FT3 level (standardized β = -0.600, P = 0.001), APACHE II score (standardized β = 0.912, P < 0.001), NT-proBNP level (standardized β = 0.459, P = 0.017) and CRP level (standardized β = 0.367, P = 0.030) could independently predict primary outcome. The addition of FT3 level to APACHE II score gave an NRI of 54.29% (P < 0.001) and an IDI of 36.54% (P < 0.001). The level of FT3 was significantly correlated with NT-proBNP levels (r = -0.344, P < 0.001) and CRP levels (r = -0.408, P < 0.001).

Conclusion

In unselected ICU patients, FT3 was the most powerful and only independent predictor of ICU mortality among the complete indicators. The addition of FT3 level to the APACHE II score could significantly improve the ability to predict ICU mortality.