NT-ProBNP in Acute Heart Failure: Correlation With Invasively Measured Hemodynamic Parameters During Recompensation

B-lines by lung ultrasound as a predictor of re-intubation in mechanically ventilated patients with heart failure

Introduction

There have been few studies on predictors of weaning failure from MV in patients with heart failure (HF). We sought to investigate the predictive value of B-lines measured by lung ultrasound (LUS) on the risk of weaning failure from mechanical ventilation (MV) and in-hospital outcomes.

Methods

This was a single-center, prospective observational study that included HF patients who were on invasive MV. LUS was performed immediate before ventilator weaning. A positive LUS exam was defined as the observation of two or more regions that had three or more count of B-lines located bilaterally on the thorax. The primary outcome was early MV weaning failure, defined as re-intubation within 72 h.

Results

A total of 146 consecutive patients (mean age 70 years; 65.8% male) were enrolled. The total count of B-lines was a median of 10 and correlated with NT-pro-BNP level (r2 = 0.132, p < 0.001). Early weaning failure was significantly higher in the positive LUS group (9 out of 64, 14.1%) than the negative LUS group (2 out of 82, 2.4%) (p = 0.011). The rate of total re-intubation during the hospital stay (p = 0.004), duration of intensive care unit stay (p = 0.004), and hospital stay (p = 0.010) were greater in the positive LUS group. The negative predictive value (NPV) of positive LUS was 97.6% for the primary outcome.

Conclusion

B-lines measured by LUS can predict the risk of weaning failure. Considering the high NPV of positive LUS, it may help guide the decision of weaning in patients on invasive MV due to acute decompensated HF.

Natriuretic peptides: role in the diagnosis and management of heart failure: a scientific statement from the Heart Failure Association of the European Society of Cardiology, Heart Failure Society of America and Japanese Heart Failure Society

Natriuretic peptides, brain (B-type) natriuretic peptide (BNP) and N-terminal prohormone of brain natriuretic peptide (NT-proBNP) are globally and most often used for the diagnosis of heart failure (HF). In addition, they can have an important complementary role in the risk stratification of its prognosis. Since the development of angiotensin receptor-neprilysin inhibitors (ARNIs), the use of natriuretic peptides as therapeutic agents has grown in importance. The present document is the result of the Trilateral Cooperation Project among the Heart Failure Association of the European Society of Cardiology, the Heart Failure Society of America and the Japanese Heart Failure Society. It represents an expert consensus that aims to provide a comprehensive, up-to-date perspective on natriuretic peptides in the diagnosis and management of HF, with a focus on the following main issues: (1) history and basic research: discovery, production and cardiovascular protection; (2) diagnostic and prognostic biomarkers: acute HF, chronic HF, inclusion/endpoint in clinical trials, and natriuretic peptide-guided therapy; (3) therapeutic use: nesiritide (BNP), carperitide (ANP) and ARNIs; and (4) gaps in knowledge and future directions.

Exercise Capacity, NT-proBNP, and Exercise Hemodynamics in Adults Post-Fontan

BACKGROUND

Cardiopulmonary exercise testing (CPET) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) measurement are frequently performed in adults post-Fontan, but their correlations with exercise invasive hemodynamics are poorly understood. Moreover, whether exercise cardiac catheterization provides incremental prognostic information is unknown.

OBJECTIVES

The authors sought to correlate resting and exercise Fontan pressures (FP) and pulmonary artery wedge pressure (PAWP) with peak oxygen consumption (VO2) on CPET, NT-proBNP, and clinical outcomes.

METHODS

This was a retrospective cohort of 50 adults (age ≥18 years) post-Fontan undergoing supine exercise venous catheterization between 2018 and 2022.

RESULTS

Median age was 31.5 years (IQR: 23.7-36.5 years). Ventricular ejection fraction was 48.5% ± 13.0%. Exercise FP and PAWP were related to peak VO2 and ln NT-proBNP levels. Patients with peak VO2 <50% predicted had higher exercise FP (30.0 ± 6.8 mm Hg vs 19 mm Hg [IQR: 16-24 mm Hg]; P < 0.001) and PAWP (25.9 ± 6.3 mm Hg vs 15.1 ± 7.0 mm Hg; P <0.001) compared with those with more preserved exercise capacity. Exercise FP (30.0 ± 7.1 mm Hg vs 23.2 ± 7.2 mm Hg; P = 0.003) and PAWP (25.1 ± 6.7 mm Hg vs 18.8 ± 7.9 mm Hg; P = 0.006) were higher in those with NT-proBNP levels ≥300 pg/mL. During a follow-up of 0.9 years (IQR: 0.6-2.9 years), exercise FP and PAWP remained independently associated with a composite of death, cardiac transplantation, or hospitalization due to heart failure/refractory arrhythmias after adjusting for confounders.

CONCLUSIONS

In adults post-Fontan, resting and exercise FP and PAWP were inversely related to exercise capacity on noninvasive CPET, and exercise hemodynamics were directly related to NT-proBNP levels. Exercise FP and PAWP were independently associated with clinical outcomes and might be more sensitive than resting values to predict clinical outcomes.

Natriuretic Peptides: Role in the Diagnosis and Management of Heart Failure: A Scientific Statement From the Heart Failure Association of the European Society of Cardiology, Heart Failure Society of America and Japanese Heart Failure Society

Natriuretic peptides, brain (B-type) natriuretic peptide (BNP) and N-terminal prohormone of brain natriuretic peptide (NT-proBNP) are globally and most often used for the diagnosis of heart failure (HF). In addition, they can have an important complementary role in the risk stratification of its prognosis. Since the development of angiotensin receptor neprilysin inhibitors (ARNIs), the use of natriuretic peptides as therapeutic agents has grown in importance. The present document is the result of the Trilateral Cooperation Project among the Heart Failure Association of the European Society of Cardiology, the Heart Failure Society of America and the Japanese Heart Failure Society. It represents an expert consensus that aims to provide a comprehensive, up-to-date perspective on natriuretic peptides in the diagnosis and management of HF, with a focus on the following main issues: (1) history and basic research: discovery, production and cardiovascular protection; (2) diagnostic and prognostic biomarkers: acute HF, chronic HF, inclusion/endpoint in clinical trials, and natriuretic peptides-guided therapy; (3) therapeutic use: nesiritide (BNP), carperitide (ANP) and ARNIs; and (4) gaps in knowledge and future directions.

ECG and Biomarker Profile in Patients with Acute Heart Failure: A Pilot Study

Background: Biomarkers, electrocardiogram (ECG) and Holter ECG are basic, accessible and feasible cardiac investigations. The combination of their results may lead to a more complex predictive model that may improve the clinical approach in acute heart failure (AHF). The main objective was to investigate which ECG parameters are correlated with the usual cardiac biomarkers (prohormone N-terminal proBNP, high-sensitive cardiac troponin I) in patients with acute heart failure, in a population from Romania. The relationship between certain ECG parameters and cardiac biomarkers may support future research on their combined prognostic value. Methods: In this prospective case-control study were included 49 patients with acute heart failure and 31 participants in the control group. For all patients we measured levels of prohormone N-terminal proBNP (NT-proBNP), high-sensitive cardiac troponin I (hs-cTnI) and MB isoenzyme of creatine phosphokinase (CK-MB) and evaluated the 12-lead ECG and 24 h Holter monitoring. Complete clinical and paraclinical evaluation was performed. Results: NT-proBNP level was significantly higher in patients with AHF (p < 0.001). In patients with AHF, NT-proBNP correlated with cQTi (p = 0.027), pathological Q wave (p = 0.029), complex premature ventricular contractions (PVCs) (p = 0.034) and ventricular tachycardia (p = 0.048). Hs-cTnI and CK-MB were correlated with ST-segment modification (p = 0.038; p = 0.018) and hs-cTnI alone with complex PVCs (p = 0.031). Conclusions: The statistical relationships found between cardiac biomarkers and ECG patterns support the added value of ECG in the diagnosis of AHF. We emphasize the importance of proper ECG analysis of more subtle parameters that can easily be missed. As a non-invasive technique, ECG can be used in the outpatient setting as a warning signal, announcing the acute decompensation of HF. In addition, the information provided by the ECG complements the biomarker results, supporting the diagnosis of AHF in cases of dyspnea of uncertain etiology. Further studies are needed to confirm long-term prognosis in a multi-marker approach.

Discharge FGF23 level predicts one year outcome in patients admitted with acute heart failure

BACKGROUND

Patients with acute heart failure (AHF) show high levels of fibroblast growth factor-23 (FGF23) on admission. We examined if plasma FGF23 changes during an episode of AHF, and if FGF23 holds prognostic significance in this setting.

METHODS

Consecutive AHF patients were enrolled. Blood samples were collected on admission and at discharge. Patients were then followed for all-cause death or HF hospitalization.

RESULTS

Patients (n = 125; median age 76 years [interquartile interval 71-83], 63% men, left ventricular ejection fraction 35% [25%-56%]) had median admission FGF23 70 ng/L (47-100), N-terminal pro-B-type natriuretic peptide (NT-proBNP) 5844 ng/L (2,503-10,468), high-sensitivity troponin T (hs-TnT) 40 ng/L (25-72), and soluble suppression of tumorigenesis-2 (sST2) 26 ng/mL (17-37). While other biomarkers decreased, FGF23 increased by 15% from admission to discharge (p = 0.033), with a significant correlation with percent changes in estimated glomerular filtration rate (rho = 0.306, p = 0.001). Over a 12-month follow-up, 64 patients (51%) experienced the endpoint. They were more often men, older, with higher systolic pulmonary artery pressure (sPAP), higher NT-proBNP, hs-TnT and discharge FGF23. The best FGF23 cut-off at discharge from receiver operating characteristics analysis was 78 ng/L. Both discharge FGF23 and the 78 ng/L cut-off independently predicted outcome in models including gender, sPAP, age, and 1) admission NT-proBNP, 2) discharge NT-proBNP, 3) admission NT-proBNP and hs-TnT, 4) discharge NT-proBNP and hs-TnT. The 78 ng/L cut-off also refined risk reclassification.

CONCLUSIONS

During an AHF episode, FGF23 increases from admission to discharge, and patients with higher discharge FGF23 have a higher risk of worse outcome.

Prognostic Value of NT-proBNP After Ischemic Stroke: A Systematic Review and Meta-analysis of Prospective Cohort Studies

BACKGROUND

Many studies have evaluated the relationship between N-terminal pro-brain natriuretic peptide (NT-proBNP) and its prognostic value in ischemic stroke. However, a widespread consensus has not been reached. Therefore, we completed a meta-analysis to evaluate the prognostic significance of NT-proBNP for mortality and functional outcome in patients with ischemic stroke.

METHODS

We performed a systematic search and review using the PubMed and EMBASE databases to identify literature that reported a correlation between NT-proBNP and mortality and functional outcome in ischemic stroke patients.

RESULTS

Eleven studies inclusive of 10,498 patients met the inclusion criteria. Elevated plasma NT-proBNP levels were associated with increased risk of mortality in ischemic stroke patients (all-cause mortality: odds ratio [OR] = 2.43, 95% confidence interval [CI] 1.62-3.64, P < .001, I²=74.3%; cardiovascular mortality: OR = 2.01, 95% CI 1.55-2.61, P < .001, I² = 42.6%). In addition, unfavorable functional outcomes were observed in patients with higher levels of NT-proBNP (OR = 1.68, 95% CI 1.13-2.50, P = .01, I² = 90.8%) after ischemic stroke.

CONCLUSIONS

This meta-analysis demonstrates that NT-proBNP could be a predictor of mortality and functional outcome in ischemic stroke patients.

An update on the use and discovery of prognostic biomarkers in acute decompensated heart failure

Introduction: Acute decompensated heart failure (ADHF) remains a significant health care burden as evidenced by high readmission rates and mortality. Over the years, the care of patients with ADHF has been transformed by the use of biomarkers, specifically to aid in the diagnosis and prognosis. Patients with HF follow a variable course given the complex and heterogenous pathophysiological processes, thus it is imperative for clinicians to have tools to predict short and long-term outcomes in order to educate patients and optimize management. Areas Covered: The natriuretic peptides, including B-type natriuretic peptide and N-terminal pro-B-type natriuretic peptide, are considered the gold standard biomarkers. Yet, other emerging biomarkers such as suppression of tumerogenicity-2, cardiac troponin, galectin-2, mid-regional pro-adrenomedullin, copeptin, cystatin, and neutrophil gelatinase-associated lipocalin have increasingly shown promise in evaluating prognosis in patients with ADHF. This article reviews the pathophysiology and utility of both established and emerging biomarkers for the prognostication of patients with ADHF. Expert Opinion: As of 2019, the most validated biomarkers for use in decompensated heart failure include natriuretic peptides, high sensitivity troponin, and sST2. These biomarkers are involved in the underlying pathophysiology of disease and as such provide added information to that of exam, x-ray, and echocardiography.

Prognostic Implications of Changes in Amino-Terminal Pro-B-Type Natriuretic Peptide in Acute Decompensated Heart Failure: Insights From ASCEND-HF

BACKGROUND

Amino-terminal pro-B-type natriuretic peptide (NTproBNP) is closely associated with prognosis in acute decompensated heart failure (ADHF). As a result, there has been great interest measuring it during the course of treatment. The prognostic implications in both short-term and follow-up changes in NTproBNP need further clarification.

METHODS

Baseline, 48-72 hour, and 30-day NTproBNP levels were measured in 795 subjects in the ASCEND-HF trial. Multivariable logistic and Cox-proportional hazards models were used to test the association between static, relative, and absolute changes in NTproBNP with outcomes during and after ADHF.

RESULTS

The median NTproBNP at baseline was 5773 (2981-11,579) pg/mL; at 48-72 hours was 3036 (1191-6479) pg/mL; and at 30 days was 2914 (1364-6667) pg/mL. Absolute changes in NTproBNP by 48-72 hours were not associated with 30-day heart failure rehospitalization or mortality (P = .065), relative changes in NTproBNP were nominally associated (P = .046). In contrast, both absolute and relative changes in NTproBNP from baseline to 48-72 hours and to 30 days were closely associated with 180-day mortality (P < .02 for all) with increased discrimination compared to the multivariable models with baseline NTproBNP (P <.05 for models with relative and absolute change at both time points).

CONCLUSIONS

Although the degree of absolute change in NTproBNP was dependent on baseline levels, both short-term absolute and relative changes in NTproBNP were independently and incrementally associated with long-term clinical outcomes. Changes in NTproBNP levels at 30-days were particularly well associated with long-term clinical outcomes.

NT-proBNP is a potential mediator between reduced ejection fraction and depression in patients with heart failure

Depression and anxiety are prevalent in patients with heart failure (HF). Reduced ejection fraction (EF) and increased N-terminal-prohormone B-type natriuretic peptide (NT-proBNP) have been shown to be independently associated with depressive symptoms and may therefore increase HF disease progression and mortality. This study evaluated whether NT-proBNP mediated the impact of reduced EF on depressive and anxiety symptoms in patients with HF. Participants (n = 124) were patients with a diagnosis of chronic HF enrolled in the Heart Failure Disease Management Program at Health Sciences North. Subjects were assessed for depressive and anxiety symptoms according to the Hospital Anxiety and Depression Scale questionnaire at enrolment. Ejection fraction, measured through Multigated Acquisition Technique and NT-proBNP, measured through chemiluminescent immunoassay, were obtained at baseline. Patient outcomes were monitored for 12-months after enrollment. Associations were determined using regression and multivariate models. Indirect effects were assessed using mediation analysis. EF and NT-proBNP were highly correlated. Mediation analysis showed no significant direct effect of EF on the levels of depressive and anxiety symptoms, however, there was a significant indirect effect of EF on depression that was mediated by the levels of NT-proBNP, but not for EF and anxiety. Our results suggest that NT-proBNP is a potential mechanism linking reduced EF and depressive symptoms in patients with HF. While results are still preliminary, this study suggests that NT-proBNP may be a potential biomarker in identifying HF patients with reduced EF at high risk for depression, disease progression and mortality.

The Effects of Continuous Positive Airway Pressure on Premature Ventricular Contractions and Ventricular Wall Stress in Patients with Heart Failure and Sleep Apnea

Background

We aimed to investigate the effects of continuous positive airway pressure (CPAP) treatment on electrocardiography (ECG), premature ventricular contraction load on 24-hour Holter recordings, and implantable cardioverter defibrillator (ICD) shocks in patients with obstructive sleep apnea syndrome (OSAS) and heart failure.

Methods

Patients with heart failure and ICD and patients with newly diagnosed OSAS were divided into two groups according to CPAP treatment. To compare the impact of CPAP on ECG parameters, both baseline and 6-month ECG, 24-hour Holter ECG, ambulatory blood pressure monitoring, echocardiography, polysomnography, and laboratory parameters were collected.

Results

CPAP treatment significantly reduced the frequency of premature ventricular contractions, T-peak to T-end, corrected QT, corrected QT dispersion, and T-peak to T-end/corrected QT ratio in the study group (p < 0.001 for all). Although the baseline NT-pro-BNP levels were similar between study and control groups, after six months, the NT-pro-BNP levels of the study group were significantly lower than that of the control group (39.18 ± 7.57 versus 46.11 ± 7.65; p < 0.001).

Conclusions

CPAP treatment in patients with heart failure and ICD and in patients with newly diagnosed OSAS may have beneficial effects on premature ventricular contractions and electrocardiographic arrhythmia indices and NT-pro-BNP levels. However, these results are needed to be clarified with further studies.

Hemodynamic Determinants of the Biologic Variation of N-Terminal Pro-B-Type Natriuretic Peptide in Patients With Stable Systolic Chronic Heart Failure

BACKGROUND CONTEXT

Biologic variation of N-terminal pro-B-type natriuretic peptide (NT-proBNP) in chronic heart failure (CHF) may affect blood levels and risk stratification. The sources of NT-proBNP variation are unknown.

METHODS AND RESULTS

We performed NT-proBNP measurements and clinical and hemodynamic assessments in 50 patients with heart failure with reduced ejection fraction (HFrEF) who met criteria for clinical stability over 2 time intervals. Hemodynamic variables were measured with the use of inert gas rebreathing and impedance cardiography. Heart rhythm was monitored with the use of external electrocardiographic event recorders throughout the study. Determinants of NT-proBNP-levels and both absolute (ΔNT-proBNP_abs) and relative (ΔNT-proBNP_%) changes at 1-week and 2-week intervals were identified with the use of univariable and multivariable linear mixed-effects models and linear regression analyses, respectively. Clinical and hemodynamic variables did not significantly change between study visits. The individual variation of NT-proBNP at 2 weeks was 9.2% (range 3.9%-18.6%). Weight and glomerular filtration rate were independently associated with baseline NT-proBNP concentrations (P = .01 and P = .005, respectively). There was no relationship between absolute and relative changes of NT-proBNP at 1-week intervals and changes in clinical and hemodynamic variables. Absolute change of NT-proBNP at 2-week intervals was associated with absolute change in left cardiac work index (P = .008), and relative change in NT-proBNP at 2-week intervals was determined by relative change of thoracic fluid content index (P = .008) and diastolic blood pressure (P = .01). The coefficients of determination (R²) for the multivariable models with Δ_1wkNT-proBNP_abs, Δ_2-weeksNT-proBNP_abs, Δ_1wkNT-proBNP_%, and Δ_2wksNT-proBNP_% as dependent variables were 0.21, 0.19, 0.10, and 0.32, respectively.

CONCLUSIONS

In patients with stable HFrEF, changes in clinical and hemodynamic variables only marginally contribute to the variation of NT-proBNP.

Congestive Heart Failure and Central Sleep Apnea

Congestive heart failure (CHF) is among the most common causes of admission to hospitals in the United States, especially in those over age 65. Few data exist regarding the prevalence CHF of Cheyne-Stokes respiration (CSR) owing to congestive heart failure in the intensive care unit (ICU). Nevertheless, CSR is expected to be highly prevalent among those with CHF. Treatment should focus on the underlying mechanisms by which CHF increases loop gain and promotes unstable breathing. Few data are available to determine prevalence of CSR in the ICU, or how CSR might affect clinical management and weaning from mechanical ventilation.

Similar hemodynamic decongestion with vasodilators and inotropes: systematic review, meta-analysis, and meta-regression of 35 studies on acute heart failure

BACKGROUND

Acute heart failure (AHF) with reduced left-ventricular ejection fraction (LVEF) is often a biventricular congested state. The comparative effect of vasodilators and inotropes on the right- and/or left-sided congestion is unknown.

METHODS AND RESULTS

A systematic review, meta-analysis, and meta-regression of AHF studies using pulmonary artery catheter were performed using PubMed, Embase, and Cochrane library. Data from 35 studies, including 3016 patients, were studied. Included patients had a weighted mean age of 60 years, left-ventricular ejection fraction (LVEF) of 24 %, and plasma B-type natriuretic peptide (BNP) of 892 pg/ml. Both the left- and right-ventricular filling pressures were elevated: weighted mean pulmonary artery wedge pressure (PAWP) was 25 mmHg (range 17-31 mmHg) and right atrial pressure (RAP) 12 mmHg (range 7-18 mmHg). Vasodilators and inotropes had similar beneficial effects on PAWP [-6.3 mmHg (95 % CI -7.4 to -5.2 mmHg) and -5.8 mmHg (95 % CI -7.6 to -4.0 mmHg), respectively] and RAP [-2.9 mmHg (95 % CI -3.8 to -2.1 mmHg) and -2.8 mmHg (95 % CI -3.8 to -1.7 mmHg), respectively]. Among inotropes, inodilators, such as levosimendan, have greater beneficial effect on the left-ventricular filling pressure than dobutamine. Drug-induced improvement of PAWP tightly paralleled that of RAP with all studied drugs (r ² = 0.90, p < 0.001). Vasodilators and inotropes had no short-term effect of renal function.

CONCLUSION

The left- and right-sided filling pressures are similarly improved by vasodilators or inotropes, in AHF with reduced LVEF.

Clinical Research on Brain Natriuretic Peptide Guiding the Application of β1 Receptor Blocker in Patients with Moderate to Severe Heart Failure

BACKGROUND

This study aimed to explore the feasibility of guiding the application of metoprolol succinate in patients with moderate to severe heart failure (HF) through monitoring plasma brain natriuretic peptide (BNP) levels.

METHODS

A total of 195 patients with moderate to severe HF (NYHA Functional Class III to IV) were selected and randomized into two groups: an observation group and a BNP group. The groups were established to observe the clinical conditions and establish plasma BNP levels to guide the application of metoprolol succinate. The average start-up of metoprolol succinate and average dose of metoprolol succinate after one month, as well as the recurrence rate and mortality of HF during hospital stay were compared between the two groups.

RESULTS

Start-up of metoprolol succinate was shorter in the BNP group than in the observation group [(5.89 ± 1.76) d vs. (7.03 ± 2.08) d, p < 0.01], but no significant differences in recurrence rate (26.60% vs. 23.91%, p > 0.05) and mortality (6.38% vs. 5.43%, p > 0.05) of HF were observed between the two groups. The average dose of metoprolol succinate after one month was higher in the BNP group compared with that of the observation group [(47.65 ± 13.09) mg/d vs. (35.08 ± 11.08) mg/d, p < 0.01].

CONCLUSIONS

Although monitoring plasma BNP might have limited the clinical impact on the change of left ventricular ejection fraction, recurrence of HF or mortality within 1 month, it could safely facilitate early use and up-titration of the metoprolol succinate in patients with moderate to severe HF.

KEY WORDS

BNP; Heart failure; β receptor blocker.

Fatigue as Presenting Symptom and a High Burden of Premature Ventricular Contractions Are Independently Associated With Increased Ventricular Wall Stress in Patients With Normal Left Ventricular Function

Background—

High idiopathic premature ventricular contractions (PVC) burden has been associated with PVC-induced cardiomyopathy. Patients may be symptomatic before left ventricular (LV) dysfunction develops. N-terminal pro–B-type natriuretic peptide (NT-proBNP) and circumferential end-systolic wall stress (cESS) on echocardiography are markers for increased ventricular wall stress. This study aimed to evaluate the relation between presenting symptoms, PVC burden, and increased ventricular wall stress in patients with frequent PVCs and preserved LV function.

Methods and Results—

Eighty-three patients (41 men; 49±15 years) with idiopathic PVCs and normal LV function referred for PVC ablation were included. Type of symptoms (palpitations, fatigue, and [near-]syncope), PVC burden on 24-hour Holter, NT-proBNP levels, and cESS on echocardiography were assessed before and 3 months after ablation. Sustained successful ablation was defined as ≥80% PVC burden reduction during follow-up. Patients were symptomatic for 24 months (Q1–Q3, 16–60); 73% reported palpitations, 47% fatigue, and 30% (near-)syncope. Baseline PVC burden was 23±13%, median NT-proBNP 92 pg/mL (Q1–Q3 50–156), and cESS 143±35 kdyne/cm 2 . Fatigue was associated with higher baseline NT-proBNP and cESS ( P <0.001, P =0.011, respectively). After sustained successful ablation, achieved in 81%, NT-proBNP and cESS decreased significantly ( P <0.001 and P =0.036, respectively). Fatigue was independently associated with a significantly larger reduction in NT-proBNP. In patients with nonsuccessful ablation, NT-proBNP and cESS remained unchanged.

Conclusions—

In patients with frequent PVCs and preserved LV function, fatigue was associated with higher baseline NT-proBNP and cESS, and with a significantly larger reduction in NT-proBNP after sustained successful ablation. These findings support a link between fatigue and PVC-induced increased ventricular wall stress, despite preserved LV function.

Congestive heart failure and central sleep apnea

Congestive heart failure (CHF) is among the most common causes of admission to hospitals in the United States, especially in those over age 65. Few data exist regarding the prevalence CHF of Cheyne-Stokes respiration (CSR) owing to congestive heart failure in the intensive care unit (ICU). Nevertheless, CSR is expected to be highly prevalent among those with CHF. Treatment should focus on the underlying mechanisms by which CHF increases loop gain and promotes unstable breathing. Few data are available to determine prevalence of CSR in the ICU, or how CSR might affect clinical management and weaning from mechanical ventilation.

Oxidative stress markers and C-reactive protein are related to severity of heart failure in patients with dilated cardiomyopathy

Background. The aim of study was to determine relationships between functional capacity (NYHA class), left ventricle ejection fraction (LVEF), hemodynamic parameters, and biomarkers of redox state and inflammation in patients with dilated cardiomyopathy (DCM). Methods. DCM patients (n = 109, aged 45.97 ± 10.82 years), NYHA class IIV, and LVEF 2.94 ± 7.1% were studied. Controls comprised age-matched healthy volunteers (n = 28). Echocardiography and right heart catheterization were performed. Serum activities of superoxide dismutase isoenzymes (MnSOD and CuZnSOD), concentrations of uric acid (UA), malondialdehyde (MDA), and C-reactive protein (hs-CRP) were measured. Results. MnSOD, UA, hs-CRP, and MDA were significantly higher in DCM patients compared to controls. Except MDA concentration, above parameters were higher in patients in III-IV NYHA class or with lower LVEF. hsCRP correlated with of MnSOD (P < 0.05) and CuZnSOD activity (P < 0.01). Both isoenzymes positively correlated with mPAP and pulmonary capillary wedge pressure (MnSOD, resp., P < 0.01 and P < 0.05 and CuZnSOD P < 0.05; P < 0.05). UA positively correlated with MnSOD (P < 0.05), mPAP (P < 0.05), and PVRI (P < 0.05). The negative correlation between LVEF and UA (P < 0.01) was detected. Conclusion. There are relationships among the severity of symptoms of heart failure, echocardiographic hemodynamic parameters, oxidative stress, and inflammatory activation. Increased MnSOD activity indicates the mitochondrial source of ROS in patients with advanced heart failure.

Usefulness of N-terminal pro-brain natriuretic peptide levels to predict success of weaning from intra-aortic balloon pumping

There is currently no reliable method of predicting the success of weaning from intra-aortic balloon pumping (IABP). The aim of this study was to investigate the ability of serum N-terminal pro-brain natriuretic peptide (NT-proBNP) level to predict the success of weaning from IABP. Consecutive patients scheduled for weaning from IABP were prospectively enrolled. NT-proBNP levels were measured at baseline (before the start of weaning) and cessation (just before cessation of IABP). Changes in NT-proBNP level between baseline and cessation were analyzed in 2 groups of patients: those who were successfully weaned and those who were not successfully weaned for any reason, including a decision to discontinue weaning, worsening of pulmonary edema after cessation of IABP, or unstable hemodynamics after cessation of IABP. A total of 30 patients were enrolled (mean age 66 ± 12 years, 16 men, 16 with acute myocardial infarctions, and 14 with acute exacerbation of chronic heart failure). Median (interquartile range) baseline NT-proBNP levels were not significantly different between the successful and unsuccessful weaning groups (4,200 [1,400 to 8,752] pg/ml vs (5,620 [2,035 to 13,950] pg/ml, p = 0.30). In the unsuccessful weaning group, the median NT-proBNP level was significantly higher at cessation (9,995 [2,920 to 15,100] pg/ml) than at baseline (p = 0.008). All patients with decreases in NT-proBNP level between baseline and cessation were successfully weaned from IABP. In conclusion, these results show that NT-proBNP levels were useful for predicting the success of weaning from IABP. If the NT-proBNP level increases during weaning from IABP, more intense management should be considered.

Changes in brain natriuretic peptide are correlated with changes in global end-diastolic volume index

BACKGROUND AND OBJECTIVE

It is believed that the stretch of cardiomyocytes is the most important stimulus of brain natriuretic peptide (BNP) release; however, its correlation with volume status represented by global end diastolic volume index (GEDVI) is less well established. The study aimed to investigate the correlation between the changes in BNP and the changes in GEDVI measured with transpulmonary thermodilution technique.

METHODS

Critically ill patients requiring hemodynamic monitoring (PiCCO system) in a tertiary 18-bed intensive care unit were prospectively enrolled. Hemodynamic variables were measured simultaneously with blood sampling for BNP concentration. Correlations between changes in BNP and changes in GEDVI were tested using pairwise correlation analysis.

RESULTS

A total of 46 patients were included in the study. BNP level (median 4,602 pg/mL; IQR 1,988 to 12,439 pg/mL) was markedly elevated in the study population, but was not correlated with GEDVI (rho=-0.09, P=0.56). The changes in BNP (ΔBNP) showed significant correlation with changes in GEDVI (ΔGEDVI) (Figure 2; rho=0.52, P<0.01). Variables including Age (r=0.43, P=0.002), serum creatinine (r=0.36, P=0.012) and cardiac index (CI) (r=-0.35, P=0.016) were also significantly correlated with logBNP. Other variables such as APACHE II score, central venous pressure (CVP), heart rate (HR), intrathoracic blood volume (ITBVI), extravascular lung water (EVLWI) and systemic vascular resistance index (SVRI) were not significantly correlated with logBNP.

CONCLUSIONS

Changes in BNP concentrations are correlated with changes in GEDVI and serial measurements of BNP concentrations may be a useful tool for monitoring volume status.

N-terminal pro-B-type natriuretic peptide-guided, intensive patient management in addition to multidisciplinary care in chronic heart failure a 3-arm, prospective, randomized pilot study

OBJECTIVES

This study was designed to investigate whether the addition of N-terminal pro-B-type natriuretic peptide-guided, intensive patient management (BM) to multidisciplinary care (MC) improves outcome in patients following hospitalization due to heart failure (HF).

BACKGROUND

Patients hospitalized due to HF experience frequent rehospitalizations and high mortality.

METHODS

Patients hospitalized due to HF were randomized to BM, MC, or usual care (UC). Multidisciplinary care included 2 consultations from an HF specialist who provided therapeutic recommendations and home care by a specialized HF nurse. In addition, BM included intensified up-titration of medication by HF specialists in high-risk patients. NT-proBNP was used to define the level of risk and to monitor wall stress. This monitoring allowed for anticipation of cardiac decompensation and adjustment of medication in advance.

RESULTS

A total of 278 patients were randomized in 8 Viennese hospitals. After 12 months, the BM group had the highest proportion of antineurohormonal triple-therapy (difference among all groups). Accordingly, BM reduced days of HF hospitalization (488 days) compared with the hospitalization for the MC (1,254 days) and UC (1,588 days) groups (p < 0.0001; significant differences among all groups). Using Kaplan-Meier analysis, the first HF rehospitalization (28%) was lower in the BM versus MC groups (40%; p = 0.06) and the MC versus UC groups (61%; p = 0.01). Moreover, the combined end point of death or HF rehospitalization was lower in the BM (37%) than in the MC group (50%; p < 0.05) and in the MC than in the UC group (65%; p = 0.04). Death rate was similar between the BM (22%) and MC groups (22%), but was lower compared with the UC group (39%; vs. BM: p < 0.02; vs. MC: p < 0.02).

CONCLUSIONS

Compared with MC alone, additional BM improves clinical outcome in patients after HF hospitalization. (BNP Guided Care in Addition to Multidisciplinary Care; NCT00355017).

Comparison of the cardiac markers B-type natriuretic peptide and N-terminal pro B-type natriuretic peptide

B-type natriuretic peptide and N-terminal pro B-type natriuretic peptide have emerged as powerful biomarkers for heart failure and other cardiovascular conditions. B-type natriuretic peptide and N-terminal pro B-type natriuretic peptide are synthesized on the basis of myocardial stress and hypertrophy and are detectable in serum by several commercially available assays. Although both markers display wide similarities in their predictive values for acute and chronic heart failure, important differences exist regarding cutoff values and influence of noncardiac variables. The similarities and differences between B-type natriuretic peptide and N-terminal pro B-type natriuretic peptide will be reviewed and illustrated in detail regarding preanalytics and analytics, predictive properties for acute and chronic heart failure and prognosis as well as the influence of noncardiac parameters.

Activation of NF-kappaB is a critical element in the antiapoptotic effect of anesthetic preconditioning

Anesthetic preconditioning (APC), defined as brief exposure to inhalational anesthetics before cardiac ischemia-reperfusion (I/R), limits injury in both animal models and in humans. APC can result in the production of reactive oxygen species (ROS), and prior work has shown that APC can modify activation of NF-kappaB during I/R, with consequent reduction in the expression of inflammatory mediators. However, the role of NF-kappaB activation before I/R is unknown. Therefore, these experiments tested the hypothesis that APC-induced ROS results in activation of NF-kappaB before I/R, with consequent increased expression of antiapoptotic proteins such as Bcl-2 and decreased apoptosis. Experiments utilized an established perfused heart rat model of sevoflurane APC and I/R. The role of NF-kappaB was defined by a novel method of transient inhibition of the regulatory kinase IKK using the reversible inhibitor SC-514. In addition to functional measures of left ventricular developed and end-diastolic pressure, phosphorylation of IkappaBalpha and activation of NF-kappaB were measured along with cytosolic protein content of Bcl-2, release of cytochrome c, and degradation of caspase-3. APC resulted in ROS-dependent phosphorylation of IkappaBalpha and activation of NF-kappaB before I/R. APC also increased the expression of Bcl-2 before I/R. In addition to functional protection following I/R, APC resulted in lower release of cytochrome c and caspase-3 degradation. These protective effects of APC were abolished by transient inhibition of IkappaBalpha phosphorylation and NF-kappaB activation by SC-514 followed by washout. ROS-dependent activation of NF-kappaB by APC before I/R is a critical element in the protective effect of APC. APC reduces apoptosis and functional impairment by increasing Bcl-2 expression before I/R. Interventions that increase NF-kappaB activation before I/R should protect hearts from I/R injury.

Natriuretic peptide determinations in critical care medicine: part of routine clinical practice or research test only?

Measurement of N-terminal pro-B-type natriuretic peptide has been shown a good rule-out test for cardiac dysfunction in patients in the intensive care unit. The peptide measurement should not be used as a replacement for other forms of monitoring, and performs best as a diagnostic test when interpreted together with other clinical findings and investigations. At a cutoff value similar to that found in other clinical studies in acute decompensated heart failure, measurement of N-terminal pro-B-type natriuretic peptide offers an additional tool for diagnostic assessment of patients presenting to the intensive care physician.

Natriuretic peptides and filling pressure at rest and stress

The natriuretic peptides are a family of compounds secreted from the atria and ventricles in response to a variety of stimuli, including increased wall stress, tachycardia, and myocardial ischemia. Increases in the levels of these compounds correlate with increased left-ventricular filling pressure in patients with systolic dysfunction, although the production of the compounds from severely impaired ventricles may be reduced, leading to lower than anticipated levels in severe heart failure. The association of increased natriuretic peptides with diastolic dysfunction has been variable, with no elevation reported in many patients with mild dysfunction. These patients with mild diastolic dysfunction become symptomatic with exercise, in association with increased filling pressure with stress, which may be documented using echocardiography or possibly the natriuretic peptide response. However, the variability of peptide levels within individuals may pose a problem to the interpretation of sequential data in response to exercise or therapies.

Advances in congestive heart failure management in the intensive care unit: B-type natriuretic peptides in evaluation of acute heart failure

BACKGROUND

Circulating concentrations of B-type natriuretic peptide (BNP) and the aminoterminal fragment (NT-proBNP) of its prohormone (proBNP) are increased in congestive heart failure in proportion to the severity of symptoms, the degree of left ventricular dysfunction, and cardiac filling pressures. Following the introduction of rapid, automated assays for determination of BNP and NT-proBNP, these peptides are increasingly used for diagnostic and prognostic purposes.

OBJECTIVE

To review studies evaluating the diagnostic and prognostic value of BNP and NT-proBNP, with special emphasis on their performance as indicators of acute heart failure in the intensive care unit.

RESULTS

In patients presenting with acute dyspnea, both BNP and NT-proBNP are accurate indicators of acute heart failure and provide prognostic information above and beyond conventional risk markers. Increased plasma levels of BNP and NT-proBNP are not specific for heart failure and may be influenced by a variety of cardiac and noncardiac conditions commonly seen in the intensive care unit, including myocardial ischemia, cardiac arrhythmias, sepsis, shock, anemia, renal failure, hypoxia, acute pulmonary embolism, pulmonary hypertension, and acute respiratory distress syndrome.

CONCLUSIONS

The diagnostic performance of BNP and NT-proBNP as indicators of acute heart failure depends on the clinical setting. In the intensive care unit, particular caution should be used in the interpretation of elevated BNP and NT-proBNP levels.

Usefulness of clinical and NT-proBNP monitoring for prognostic guidance in destabilized heart failure outpatients

AIMS

To study the relative prognostic value of N-terminal pro-B-type natriuretic peptide (NT-proBNP) monitoring in addition to clinical disease severity scores (CDSSs) in outpatients with destabilized heart failure (HF).

METHODS AND RESULTS

Seventy-one outpatients with recently destabilized HF were recruited. At baseline, and at all following visits, a CDSS based on Framingham criteria was obtained, and NT-proBNP levels were measured in a blind fashion. CDSS did not correlate with NT-proBNP levels at any time (P > 0.1), although their relative changes correlated during follow-up (P < 0.001). Forty patients (56%) had clinical events (cardiovascular death and/or HF hospitalization) within 1 year of follow-up. Changes in CDSS from baseline were not predictive of subsequent events (P > 0.1 for all visits), whereas changes in NT-proBNP levels were predictive at several time points: week 2 (P = 0.005), week 3 (P = 0.037), week 4 (P = 0.015), and 6 months (P = 0.026). A change in NT-proBNP levels at follow-up week 2 (%) added independent prognostic information (P < 0.001, HR 0.982, 95% CI 0.972-0.992) to baseline CDSS (P = 0.002, HR 2.05, 95% CI 1.290-3.266), age (P = 0.007, HR 1.034, 95% CI 1.009-1.059), and left ventricular ejection fraction (P = 0.013, HR 0.942, 95% CI 0.898-0.987).

CONCLUSION

Serial monitoring for per cent change in NT-proBNP concentrations offers superior prognostic information to clinical assessment among outpatients with recent destabilized HF.

Amino-terminal pro-B-type natriuretic peptide testing for inpatient monitoring and treatment guidance of acute destabilized heart failure

Although typically elevated at presentation in the context of destabilized heart failure (HF), amino-terminal pro-B-type natriuretic peptide (NT-proBNP) values typically decrease rapidly among patients who have a favorable response to therapy. Given this, it is natural to examine the relation between NT-proBNP and therapeutic interventions for acute HF. Both presentation and posttreatment NT-proBNP concentrations have some value for prognostication of recurrent HF hospitalization or death. However, the percent change in NT-proBNP after treatment for acute HF may be a more powerful method for risk stratification. Although prospective studies on the effect of NT-proBNP measurement in guiding therapy in acute destabilized HF are lacking, observational data suggest that a 30% decrease in NT-proBNP values during hospitalization is a reasonable goal. If a baseline measure of NT-proBNP is not available, an NT-proBNP level <4,000 ng/L after acute treatment is an alternative goal. Because the criteria for determining restabilization from destabilized HF prominently include clinical and routine laboratory testing rather than NP measures, the frequency of NT-proBNP measurement should not be excessive in patients with acute HF, with measures at baseline/presentation and after perceived recompensation to evaluate for the desired decrease in NT-proBNP concentrations. A remeasurement of NT-proBNP may also be useful for evaluation of new or worsened symptoms. In those patients without a decrease in NT-proBNP despite perceived recompensation from HF, a review of adequacy of treatment, goals of therapy, and consideration of prognosis is recommended.

Screening and therapy of pulmonary hypertension in systemic sclerosis

PURPOSE OF REVIEW

Systemic sclerosis is a major risk factor for the development of pulmonary arterial hypertension. Often this disease is far advanced by the time it is detected in the individual patient, severely impacting quality of life and survival.

RECENT FINDINGS

Therapeutic options available for patients with scleroderma-associated pulmonary arterial hypertension have increased significantly over the last few years, fueling our desire to improve early detection of disease.

SUMMARY

During the course of this manuscript I will review the literature examining approaches towards screening for scleroderma-associated pulmonary arterial hypertension. I will then discuss the most recent studies examining therapeutic options for patients with this disease.

N-terminal pro-B-type natriuretic peptide is an independent predictor of outcome in an unselected cohort of critically ill patients*

OBJECTIVES

Natriuretic peptides emerged during recent years as potent prognostic markers in patients with heart failure and acute myocardial infarction. In addition, natriuretic peptides show strong predictive value in patients with pulmonary embolism, sepsis, renal failure, and shock. The present study tests the prognostic information of N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) in an unselected cohort of critically ill patients.

DESIGN

Prospective, observational study.

SETTING

A tertiary intensive care unit in a university hospital.

PATIENTS

A total of 289 consecutive patients admitted to the intensive care unit during a 16-month period with the following data: age 64 +/- 14 yrs, male n = 191, Simplified Acute Physiology Score II of 52 +/- 24, mechanical ventilation n = 180 (62%), vasopressors n = 179 (62%), renal failure n = 24 (8%).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Plasma NT-pro-BNP samples (Roche Diagnostics) were obtained on intensive care unit admission. Data are given as median [range]. Intensive care unit survivors had significantly lower NT-pro-BNP values compared with intensive care unit nonsurvivors (3394 [24-35,000] vs. 6776 [303-35,000] pg/mL, survivors vs. nonsurvivors, respectively, p = .001). Hospital survivors were characterized by significantly lower NT-pro-BNP values (2656 [24-35,000] vs. 8390 [303-35,000] pg/mL, survivors vs. nonsurvivors, respectively, p = .001). NT-pro-BNP levels were not significantly different in patients with primary cardiac diagnosis compared with those with a noncardiac admission diagnosis (4794 [26-35,000], n = 202 vs. 3349 [24-35,000], n = 87, cardiac vs. noncardiac, respectively, p = .28). In a logistic regression model, Simplified Acute Physiology Score II and NT-pro-BNP were independently associated with hospital survival (chi = 35.6, p = .0001 and chi = 11.3, p = .0008, Simplified Acute Physiology Score II and NT-pro-BNP, respectively). Areas under the receiver operating characteristic curves of NT-pro-BNP and Simplified Acute Physiology Score II were not statistically significant different regarding the prediction of outcome.

CONCLUSIONS

NT-pro-BNP on admission is an independent prognostic marker of outcome in an unselected cohort of critically ill patients. A single measurement of NT-pro-BNP might facilitate triage of emergency and intensive care unit patients.

In critically ill patients, B-type natriuretic peptide (BNP) and N-terminal pro-BNP levels correlate with C-reactive protein values and leukocyte counts

BACKGROUND

B-type natriuretic peptide (BNP) and its N-terminal portion (NT-pro-BNP) are used for the assessment of cardiac dysfunction in patients with heart failure. However, it remains controversial whether or not this option is still valid in critically ill patients because of a possible interaction between the systemic inflammatory response and the natriuretic peptide levels. The aim of this study was to assess the relationship between natriuretic peptic levels, laboratory parameters of systemic inflammation, and pulmonary artery occlusion pressure (PAOP) in critically patients.

METHODS

Twelve haemodyamic unstable patients, all monitored with a pulmonary artery catheter, were included in this study. Subgroups were compared using measurement values on ICU admission. Within patient associations between different variables were evaluated by a repeated measurement ancova.

RESULTS

Acute heart failure and septic shock were diagnosed in 6 patients each. Despite significant differences in cardiac index and troponin T plasma level, BNP and NT-pro-BNP levels did not differ significantly between the two groups. Within patient, changes in BNP and NT-pro-BNP levels correlated significantly (p<0.01) with those in C-reactive protein values and those in leukocyte counts, but did not follow changes in PAOP.

CONCLUSION

Our results add further evidence to the hypothesis that there is an interaction between the systemic inflammatory response and the natriuretic peptides. Thus, BNP and NT-pro-BNP levels should only be used cautiously as surrogates of cardiac filling and function in haemodynamic unstable critically ill patients.

Severe septic inflammation as a strong stimulus of myocardial NT-pro brain natriuretic peptide release

BACKGROUND

Septic shock (SS) has recently been identified as stimulus of N-terminal pro-brain natriuretic peptide (NT-proBNP) release. We tested whether SS mediates NT-proBNP release through cardiomyocyte necrosis. Moreover, the discriminative value of NT-proBNP for the distinction between SS and non-septic shock (NSS) was assessed.

METHODS

The study included 50 ICU patients with SS (n=25) and NSS (n=25), 40 patients with acute coronary syndrome and elevated troponin-I (ACStrop+) and 16 patients with unstable angina and normal troponin-I (UAtrop-). Eleven subjects without inflammation or cardiac disease served as controls. NT-proBNP levels of coronary patients were measured on admission, those of ICU patients 48 h after onset of shock symptoms.

RESULTS

ACStrop+ (1525 [25th-75th percentile: 790-3820] pg/L) and NSS (687 [254-1552]) patients showed increased NT-proBNP levels above those of UAtrop- patients (107 [43-450], p<0.001) and controls (52 [42-99], p<0.001), but SS patients exhibited still higher levels (11,335 [4716-25,769], p<0.001 vs all others). Among ICU patients with shock symptoms, NT-proBNP discriminated SS and NSS with high sensitivity and specificity (area under ROC curve: 0.946 [95% confidence interval, 0.872-1.019]). NT-proBNP correlated with troponin-I, as marker of cardiomyocyte damage, among ACStrop+ (p<0.001) and SS patients (p=0.013). But, whereas SS patients showed the greatest NT-proBNP values, ACStrop+ patients had higher troponin-I levels (p<0.001), suggesting different mechanisms by which myocardial ischemia and SS mediate NT-proBNP release.

CONCLUSIONS

SS is a more potent stimulus of NT-proBNP release than myocardial ischemia. NT-proBNP reliably distinguishes SS from other forms of shock. SS-related NT-proBNP release appears to involve cardiomyocyte damage but not genuine cardiomyocyte necrosis.

B-type natriuretic peptide (BNP) is more sensitive to rapid hemodynamic changes in acute heart failure than N-terminal proBNP

BACKGROUND

We examined whether B-type natriuretic peptide (BNP) and its precursor fragment, N-terminal proBNP (NT-proBNP), can serve as non-invasive markers of hemodynamic response to treatment in acute heart failure in a prospective observational study.

METHODS

29 unselected, consecutive patients (mean age: 61.6, 39-83 years; 25 males, 4 females) in urgent need for positive inotropic support and invasive hemodynamic monitoring by a Swan-Ganz catheter. Positive hemodynamic response to treatment was defined as > or =25% decrease in pulmonary artery occlusion pressure after 24 h. Hemodynamics were recorded simultaneously with blood sampling for BNP and NT-proBNP testing before and 24 h after initiation of inotropic support. BNP (Bayer Diagnostics) and NT-proBNP (Roche Diagnostics) were measured by commercial immunoassays.

RESULTS

Both markers were markedly elevated. However, there were no close correlations (r<0.43, p<0.05) of BNP or NT-proBNP with hemodynamic parameters at baseline or 24 h thereafter. Only BNP showed a significant (p=0.023) decrease compared to baseline values in hemodynamic responders. The area under receiver operating characteristics curve for relative changes of BNP for the prediction of hemodynamic response was 0.76.

CONCLUSIONS

Our preliminary results indicate that BNP is more sensitive to acute hemodynamic changes than NT-proBNP. This study also highlights limitations of both markers as surrogates of hemodynamics in critically ill acute heart failure patients.

Natriuretic peptide testing for the evaluation of critically ill patients with shock in the intensive care unit: a prospective cohort study

Introduction

Amino-terminal pro-brain natriuretic peptide (NT-proBNP) is useful in evaluating heart failure, but its role in evaluating patients with shock in the intensive care unit (ICU) is not clear.

Method

Forty-nine consecutive patients in four different ICUs with shock of various types and with an indication for pulmonary artery catheter placement were evaluated. Analyses for NT-proBNP were performed on blood obtained at the time of catheter placement and results were correlated with pulmonary artery catheter findings. Logistic regression identified independent predictors of mortality.

Results

A wide range of NT-proBNP levels were observed (106 to >35,000 pg/ml). There was no difference in median NT-proBNP levels between patients with a cardiac and those with a noncardiac origin to their shock (3,046 pg/ml versus 2,959 pg/ml; P = 0.80), but an NT-proBNP value below 1,200 pg/ml had a negative predictive value of 92% for cardiogenic shock. NT-proBNP levels did not correlate with filling pressures or hemodynamics (findings not significant). NT-proBNP concentrations were higher in patients who died in the ICU (11,859 versus 2,534 pg/ml; P = 0.03), and the mortality rate of patients in the highest log-quartile of NT-proBNP (66.7%) was significantly higher than those in other log-quartiles (P < 0.001); NT-proBNP independently predicted ICU mortality (odds ratio 14.8, 95% confidence interval 1.8–125.2; P = 0.013), and was superior to Acute Physiology and Chronic Health Evaluation II score and brain natriuretic peptide in this regard.

Conclusion

Elevated levels of NT-proBNP do not necessarily correlate with high filling pressures among patients with ICU shock, but marked elevation in NT-proBNP is strongly associated with ICU death. Low NT-proBNP values in patients with ICU shock identifed those at lower risk for death, and may be useful in excluding the need for pulmonary artery catheter placement in such patients.

Changes in Plasma N-Terminal proBNP Levels and Ventricular Filling Pressures During Intensive Unloading Therapy in Elderly With Decompensated Congestive Heart Failure and Preserved Left Ventricular Systolic Function

BACKGROUND

Plasma B-type natriuretic peptide (BNP) levels depend on left ventricular (LV) filling pressures and correlate with the state of neurohormonal modulation in patients with congestive heart failure (CHF). In these subjects, therapy of decompensated CHF can determine acute changes in BNP levels.

METHODS AND RESULTS

We defined the sequential pattern of N-terminal (T) proBNP in elderly with decompensated CHF and preserved LV systolic function undergoing intensive unloading therapy, assessed the prevalence of patients who significantly reduced NTproBNP at the end of treatment, and verified the relations between changes in NTproBNP and ventricular filling pressures. NTproBNP was measured in 30 patients hospitalized for worsening CHF with LV ejection fraction >50% at admission and after 2 to 4 and 6 to 8 days from the start of treatment. Patients who exhibited a reduction in NTproBNP >35% from baseline to 8-day evaluation were defined as "responders." Twelve healthy subjects matched for age and sex were used as controls. NTproBNP was significantly higher in CHF patients than controls in all time points, to a greater extent in baseline evaluation (2982 [lower/upper quartile 1273/8146] versus 235 [150/280] pg/mL). A progressive, linear reduction of NTproBNP was detected in CHF patients during unloading. At Day 8, 18 patients (60%) resulted in "responders," whereas 12 (40%) were "nonresponders." The former could be predicted through higher pulmonary artery wedge pressure at baseline. Surprisingly, ventricular filling pressures similarly declined in responders and non responders. At Day 8, NTproBNP was yet 7-fold higher in CHF patients than controls.

CONCLUSION

Intensive unloading therapy is associated with a significant short-term reduction in NTproBNP in elderly with CHF and preserved LV systolic function. This behavior is progressive and linear during the first week and parallels a reduction in ventricular filling pressures which, however, does not differ between patients who significantly reduce NTproBNP and those who do not. Thus the short-term changes in NTproBNP during intensive unloading therapy in our patients do not depend only on the acute improvement in hemodynamic conditions.

Clinical relevance of biological variation: the lesson of brain natriuretic peptide (BNP) and NT-proBNP assay

The clinical relevance of brain natriuretic peptide (BNP) and N-terminal (NT)-proBNP assays as a diagnostic tool and prognostic marker in patients with cardiovascular diseases has recently been confirmed. However, several studies demonstrated variation of intra-individual BNP concentrations of >30% (ranging from 30% to 50%) with reference change values at the 95% confidence interval (i.e., the estimated critical difference) ranging from 99% to 130% in healthy subjects and heart failure patients. According to this estimated confidence interval, only a great variation in plasma BNP levels should be considered significant in an individual patient (for example, a decrease of >50% or an increase of more than two-fold). Many recent clinical studies have demonstrated that BNP variations below this estimated critical difference could also have clinical relevance. Like the concentration of other neuro-hormones, levels of plasma BNP fluctuate widely and rapidly along with heart rhythm and blood pressure variations in response to physiological stimuli. However, biological variation of BNP should not be interpreted strictly as random fluctuation around a homeostatic set point, as assumed by the common model used in all studies on biological variation of BNP reported in the literature. These results cannot be directly transferred to clinical practice. While awaiting more accurate studies, we suggest that variations of plasma BNP three-fold greater than the analytical imprecision should be considered as potentially relevant from a physiological and clinical point of view.