[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.

Continuing chronic beta-blockade in the acute phase of severe sepsis and septic shock is associated with decreased mortality rates up to 90 days

Background

There is growing evidence that beta-blockade may reduce mortality in selected patients with sepsis. However, it is unclear if a pre-existing, chronic oral beta-blocker therapy should be continued or discontinued during the acute phase of severe sepsis and septic shock.

Methods

The present secondary analysis of a prospective observational single centre trial compared patient and treatment characteristics, length of stay and mortality rates between adult patients with severe sepsis or septic shock, in whom chronic beta-blocker therapy was continued or discontinued, respectively. The acute phase was defined as the period ranging from two days before to three days after disease onset. Multivariable Cox regression analysis was performed to compare survival outcomes in patients with pre-existing chronic beta-blockade.

Results

A total of 296 patients with severe sepsis or septic shock and pre-existing, chronic oral beta-blocker therapy were included. Chronic beta-blocker medication was discontinued during the acute phase of sepsis in 129 patients and continued in 167 patients. Continuation of beta-blocker therapy was significantly associated with decreased hospital (P=0.03), 28-day (P=0.04) and 90-day mortality rates (40.7% vs 52.7%; P=0.046) in contrast to beta-blocker cessation. The differences in survival functions were validated by a Log-rank test (P=0.01). Multivariable analysis identified the continuation of chronic beta-blocker therapy as an independent predictor of improved survival rates (HR = 0.67, 95%-CI (0.48, 0.95), P=0.03).

Conclusions

Continuing pre-existing chronic beta-blockade might be associated with decreased mortality rates up to 90 days in septic patients.

How peptide technology has improved costs and outcomes in patients with heart failure

INTRODUCTION

Heart failure (HF) is characterized by substantial health and economic burden, mainly attributed to increased hospitalizations and readmissions. Its diagnosis remains challenging due to the non-specific nature of the initial symptoms of the disease. Recently, scientific evidence has highlighted the potential of natriuretic peptides (NP) in improving the diagnosis and prognosis of HF and, by extension, in restraining healthcare costs. The present review aimed at providing evidence of their optimal use in terms of economic and health outcomes.

AREAS COVERED

Systematic literature research limited to studies published from February 2006 to February 2016 was performed with the aim of identifying and analyzing all cost-effectiveness and other economic evaluation studies that investigated the economic and health outcomes of NPs use as screening and management tools for HF. Expert commentary: NP testing either added in the standard of care, or substituting frequently used diagnostic procedures for the diagnosis and management of HF, regardless of the healthcare setting of interest, was proved to be a valid tool for clinical decision-making. Moreover it was associated with improved patient outcomes and important cost-savings mainly attributed to lower admission and readmission rates, shorter hospitalization length and improved health-related quality of life.

B-type natriuretic peptide in the evaluation and management of dyspnoea in primary care

OBJECTIVES

The rapid and accurate diagnosis of heart failure in primary care is a major unmet clinical need. We evaluated the additional use of B-type natriuretic peptide (BNP) levels.

DESIGN

A randomized controlled trial.

SETTING

Twenty-nine primary care physicians in Switzerland and Germany coordinated by the University Hospital Basel, Switzerland.

SUBJECTS

A total of 323 consecutive patients presenting with dyspnoea.

INTERVENTIONS

Assignment in a 1 : 1 ratio to a diagnostic strategy including point-of-care measurement of BNP (n = 163) or standard assessment without BNP (n = 160). The total medical cost at 3 months was the primary end-point. Secondary end-points were diagnostic certainty, time to appropriate therapy, functional capacity, hospitalization and mortality. The final diagnosis was adjudicated by a physician blinded to the BNP levels.

RESULTS

Heart failure was the final diagnosis in 34% of patients. The number of hospitalizations, functional status and total medical cost at 3 months [median $1655, interquartile range (IQR), 850-3331 vs. $1541, IQR 859-2827; P = 0.68] were similar in both groups. BNP increased diagnostic certainty as defined by the need for further diagnostic work-up (33% vs. 45%; P = 0.02) and accelerated the initiation of the appropriate treatment (13 days vs. 25 days; P = 0.01). The area under the receiver-operating characteristics curve for BNP to identify heart failure was 0.87 (95% confidence interval, 0.81-0.93).

CONCLUSIONS

The use of BNP levels in primary care did not reduce total medical cost, but improved some of the secondary end-points including diagnostic certainty and time to initiation of appropriate treatment.

Heart failure highlights in 2011

Heart failure (HF) remains a major medical problem, and the European Journal of Heart Failure is dedicated to publishing research further investigating its pathophysiology and diagnosis in order to help clinicians alleviate symptoms and improve patient outcomes.( 1) This review reports on important studies in the field of HF published in 2011. All research areas are addressed, including experimental studies, biomarkers, clinical trials, arrhythmias, and new insights into the role of device therapy.

Growth-differentiation factor-15 improves reclassification for the diagnosis of heart failure with normal ejection fraction in morbid obesity

AIMS

This study aimed to examine the incremental value of growth-differentiation factor-15 (GDF-15) to N-terminal pro brain natriuretic hormone (NT-proBNP) levels for the diagnosis of left ventricular diastolic dysfunction (LVDD) and possible heart failure (HF) in morbidly obese patients. Method and results We analysed data from 207 obese subjects [body mass index (BMI) 41 ± 8 kg/m(2)] with normal ejection fraction, LVDD, and symptoms and/or signs of HF (referred to as 'LVDD with possible HF', n = 88) and with normal left ventricular function (n = 119) before participating in a medical weight loss programme, in addition to the study of healthy lean subjects (n = 51). Median NT-proBNP (interquartile range) for obese subjects with 'LVDD and possibe HF' and with normal LV function was 52 (29-96) and 42 (25-66) pg/mL, respectively (P = 0.12). There was no correlation of NT-proBNP with parameters of left ventricular filling pressure, i.e. E/E' (r(2) = 0.002, P = 0.63) or E' velocity (r(2) = 0.02, P = 0.24). In contrast, GDF-15 was 665 (496-926) with 'LVDD and possible HF' and 451 (392- 679) pg/mL without (P < 0.0001). GDF-15 was significantly correlated to E/E', E' velocity, E/A ratio, isovolumetric relaxation time, duration of reversed pulmonary vein atrial systolic flow, and left atrial size. The area under the receiver operating characteristic curve that defines LVDD with possible HF was 0.56 for NT-proBNP and 0.74 for GDF-15 (P < 0.0001). The addition of GDF-15 to a multivariate predicition model increased the net reclassification improvement (NRI) by 9% (P= 0.022).

CONCLUSION

In morbidly obese individuals, GDF-15 levels seem to better correlate with diastolic dysfunction than NT-proBNP levels. GDF-15 significantly improves reclassification for the diagnosis of 'LVDD with possible HF' and, thus, adds incremental value to NT-proBNP.

Value of arterial blood gas analysis in patients with acute dyspnea: an observational study

Introduction

The diagnostic and prognostic value of arterial blood gas analysis (ABGA) parameters in unselected patients presenting with acute dyspnea to the Emergency Department (ED) is largely unknown.

Methods

We performed a post-hoc analysis of two different prospective studies to investigate the diagnostic and prognostic value of ABGA parameters in patients presenting to the ED with acute dyspnea.

Results

We enrolled 530 patients (median age 74 years). ABGA parameters were neither useful to distinguish between patients with pulmonary disorders and other causes of dyspnea nor to identify specific disorders responsible for dyspnea. Only in patients with hyperventilation from anxiety disorder, the diagnostic accuracy of pH and hypoxemia rendered valuable with an area under the receiver operating characteristics curve (AUC) of 0.86. Patients in the lowest pH tertile more often required admission to intensive care unit (28% vs 12% in the first tertile, P < 0.001) and had higher in-hospital (14% vs 5%, P = 0.003) and 30-day mortality (17% vs 7%, P = 0.002). Cumulative mortality rate was higher in the first (37%), than in the second (28%), and the third tertile (23%, P = 0.005) during 12 months follow-up. pH at presentation was an independent predictor of 12-month mortality in multivariable Cox proportional hazard analysis both for patients with pulmonary (P = 0.043) and non-pulmonary disorders (P = 0.038).

Conclusions

ABGA parameters provide limited diagnostic value in patients with acute dyspnea, but pH is an independent predictor of 12 months mortality.

Utile or futile: biomarkers in the ICU

Biomarkers complement other clinical information by proving quantitative data regarding a pathophysiological mechanism that can be used for the early diagnosis of a specific disease, to monitor and guide treatment, and to predict the risk of death or other adverse events. The stronger the link between the information provided by the biomarker and the immediate clinical course of action that we physicians take in response, the higher the clinical utility of the biomarker. This link is weakest for prognostic biomarkers applied in patients with a wide variety of diseases, such as in unselected intensive care unit (ICU) patients. Although the added value on top of current ICU mortality scores seems to be too low to justify clinical use, the observation that hemodynamic cardiac stress and inflammation are present in multiple conditions provides important insights into the pathophysiology of common disorders in the ICU.

Direct comparison of serial B-type natriuretic peptide and NT-proBNP levels for prediction of short- and long-term outcome in acute decompensated heart failure

Introduction

Monitoring treatment efficacy and assessing outcome by serial measurements of natriuretic peptides in acute decompensated heart failure (ADHF) patients may help to improve outcome.

Methods

This was a prospective multi-center study of 171 consecutive patients (mean age 80 73-85 years) presenting to the emergency department with ADHF. Measurement of BNP and NT-proBNP was performed at presentation, 24 hours, 48 hours and at discharge. The primary endpoint was one-year all-cause mortality; secondary endpoints were 30-days all-cause mortality and one-year heart failure (HF) readmission.

Results

During one-year follow-up, a total of 60 (35%) patients died. BNP and NT-proBNP levels were higher in non-survivors at all time points (all P < 0.001). In survivors, treatment reduced BNP and NT-proBNP levels by more than 50% (P < 0.001), while in non-survivors treatment did not lower BNP and NT-proBNP levels. The area under the ROC curve (AUC) for the prediction of one-year mortality increased during the course of hospitalization for BNP (AUC presentation: 0.67; AUC 24 h: 0.77; AUC 48 h: 0.78; AUC discharge: 0.78) and NT-proBNP (AUC presentation: 0.67; AUC 24 h: 0.73; AUC 48 h: 0.75; AUC discharge: 0.77). In multivariate analysis, BNP at 24 h (1.02 [1.01-1.04], P = 0.003), 48 h (1.04 [1.02-1.06], P < 0.001) and discharge (1.02 [1.01-1.03], P < 0.001) independently predicted one-year mortality, while only pre-discharge NT-proBNP was predictive (1.07 [1.01-1.13], P = 0.016). Comparable results could be obtained for the secondary endpoint 30-days mortality but not for one-year HF readmissions.

Conclusions

BNP and NT-proBNP reliably predict one-year mortality in patients with ADHF. Prognostic accuracy of both biomarker increases during the course of hospitalization. In survivors BNP levels decline more rapidly than NT-proBNP levels and thus seem to allow earlier assessment of treatment efficacy. Ability to predict one-year HF readmission was poor for BNP and NT-proBNP.

Trial registration

ClinicalTrials.gov identifier: NCT00514384.

Effect of oral β-blocker on short and long-term mortality in patients with acute respiratory failure: results from the BASEL-II-ICU study

INTRODUCTION

Acute respiratory failure (ARF) is responsible for about one-third of intensive care unit (ICU) admissions and is associated with adverse outcomes. Predictors of short- and long-term outcomes in unselected ICU-patients with ARF are ill-defined. The purpose of this analysis was to determine predictors of in-hospital and one-year mortality and assess the effects of oral beta-blockers in unselected ICU patients with ARF included in the BASEL-II-ICU study.

METHODS

The BASEL II-ICU study was a prospective, multicenter, randomized, single-blinded, controlled trial of 314 (mean age 70 (62 to 79) years) ICU patients with ARF evaluating impact of a B-type natriuretic peptide- (BNP) guided management strategy on short-term outcomes.

RESULTS

In-hospital mortality was 16% (51 patients) and one-year mortality 41% (128 patients). Multivariate analysis assessed that oral beta-blockers at admission were associated with a lower risk of both in-hospital (HR 0.33 (0.14 to 0.74) P = 0.007) and one-year mortality (HR 0.29 (0.16 to 0.51) P = 0.0003). Kaplan-Meier analysis confirmed the lower mortality in ARF patients when admitted with oral beta-blocker and further shows that the beneficial effect of oral beta-blockers at admission holds true in the two subgroups of patients with ARF related to cardiac or non-cardiac causes. Kaplan-Meier analysis also shows that administration of oral beta-blockers before hospital discharge gives striking additional beneficial effects on one-year mortality.

CONCLUSIONS

Established beta-blocker therapy appears to be associated with a reduced mortality in ICU patients with acute respiratory failure. Cessation of established therapy appears to be hazardous. Initiation of therapy prior to discharge appears to confer benefit. This finding was seen regardless of the cardiac or non-cardiac etiology of respiratory failure.

TRIAL REGISTRATION

clinicalTrials.gov Identifier: NCT00130559.