Biomarker-Guided Treatment of Heart Failure

The multidimensional value of natriuretic peptides in heart failure, integrating laboratory and clinical aspects

Natriuretic peptides (NP) play an essential role in heart failure (HF) regulation, and their measurement has improved diagnostic and prognostic accuracy. Clinical symptoms and objective measurements, such as NP levels, should be included in the HF definition to render it more reliable and consistent among observers, hospitals, and healthcare systems. BNP and NT-proBNP are reasonable surrogates for cardiac disease, and their measurement is critical to early diagnosis and risk stratification of HF patients. NPs should be measured in all patients presenting with dyspnea or other symptoms suggestive of HF to facilitate early diagnosis and risk stratification. Both BNP and NT-proBNP are currently used for guided HF management and display comparable diagnostic and prognostic accuracy. Standardized cutoffs for each NP assay are essential for data comparison. The value of NP testing is recognized at various levels, including patient empowerment and education, analytical and operational issues, clinical HF management, and cost-effectiveness.

Natriuretic peptide-guided therapy: further research required for still-unresolved issues

It has been asserted that serial measurements of natriuretic peptides (NPs), i.e., B-type natriuretic peptide (BNP) or the amino-terminal fragment of pro-B-type natriuretic peptide (NT-pro BNP), could help modulate more accurately the intensity of drug treatment in patients with chronic heart failure (CHF). Nevertheless, there are still several open questions about the presumed role of NP-guided pharmacologic adjustment as a valuable strategy in this setting. In this review, we outline the main randomized controlled trials (RCTs) carried out to date regarding NP-guided therapy in CHF patients and we focus on some of the still-unresolved issues. In particular, we discuss which NP plasma level should be assumed as the optimal target level to be attained, and we debate the possible influence exerted by different age classes on clinical end points during NP-guided therapy. The possible advantages and limitations for the cardiovascular system arising from the functional activation of NPs in CHF patients are also discussed. Although the pooling of data derived from the RCTs demonstrates an overall effect of slightly significant improvement in clinical outcomes with the NP-guided approach, we have noted that there are some relatively large studies that failed to document a significant clinical improvement in terms of mortality and morbidity using an NP-guided strategy. Thus, in our opinion, larger and better conducted trials addressing the unresolved issues of NP-guided therapy should be undertaken in the future.

Novel biomarkers in chronic heart failure

Understanding of chronic heart failure (HF) has progressed from a syndrome of disordered hemodynamics caused by alterations in the structure of the heart to one that involves intertwined molecular pathways in disarray. Accordingly, the assessment and treatment of patients with chronic HF has shifted from a focus on hemodynamics to modification of maladaptive molecular processes. Accumulating evidence shows that molecular biomarkers of disease could provide a unique window into the pathophysiology of chronic HF, potentially improving our ability to predict adverse outcomes, provide novel drug targets, and even help gauge therapeutic efficacy. The more 'traditional' biomarkers such as cardiac troponin, natriuretic peptides, and C-reactive protein have been studied in large cohorts of patients with chronic HF and have relatively established clinical applications. In this Review, we summarize the properties, clinical data, and potential applications of some emerging biomarkers that could uniquely indicate the level of biomechanical stretch, inflammation, ventricular remodeling, myocardial injury, and renal dysfunction that occurs in chronic HF. We will also discuss the potential role for these biomarkers within a multimarker-based strategy that could, in the future, lead to better care for these patients.

Heart failure treatment in the elderly

Heart failure is a growing epidemic, particularly in the elderly. As a consequence, we will see a greater number of elderly patients with heart failure in our practices. Elderly heart failure patients have not been well studied. Data suggest that most medical and other therapies are appropriate for elderly individuals. This article identifies the available data regarding treatment of heart failure in elderly patients.

Use of amino-terminal pro-B-type natriuretic peptide to guide outpatient therapy of patients with chronic left ventricular systolic dysfunction

OBJECTIVES

The aim of this study was to evaluate whether chronic heart failure (HF) therapy guided by concentrations of amino-terminal pro-B-type natriuretic peptide (NT-proBNP) is superior to standard of care (SOC) management.

BACKGROUND

It is unclear whether standard HF treatment plus a goal of reducing NT-proBNP concentrations improves outcomes compared with standard management alone.

METHODS

In a prospective single-center trial, 151 subjects with HF due to left ventricular (LV) systolic dysfunction were randomized to receive either standard HF care plus a goal to reduce NT-proBNP concentrations ≤1,000 pg/ml or SOC management. The primary endpoint was total cardiovascular events between groups compared using generalized estimating equations. Secondary endpoints included effects of NT-proBNP-guided care on patient quality of life as well as cardiac structure and function, assessed with echocardiography.

RESULTS

Through a mean follow-up period of 10 ± 3 months, a significant reduction in the primary endpoint of total cardiovascular events was seen in the NT-proBNP arm compared with SOC (58 events vs. 100 events, p = 0.009; logistic odds for events 0.44, p = 0.02); Kaplan-Meier curves demonstrated significant differences in time to first event, favoring NT-proBNP-guided care (p = 0.03). No age interaction was found, with elderly patients benefitting similarly from NT-proBNP-guided care as younger subjects. Compared with SOC, NT-proBNP-guided patients had greater improvements in quality of life, demonstrated greater relative improvements in LV ejection fraction, and had more significant improvements in both LV end-systolic and -diastolic volume indexes.

CONCLUSIONS

In patients with HF due to LV systolic dysfunction, NT-proBNP-guided therapy was superior to SOC, with reduced event rates, improved quality of life, and favorable effects on cardiac remodeling. (Use of NT-proBNP Testing to Guide Heart Failure Therapy in the Outpatient Setting; NCT00351390).

Emerging biomarkers in heart failure

BACKGROUND

Until recently, biomarker testing in heart failure (HF) syndromes has been viewed as an elective supplement to diagnostic evaluation of patients suspected to suffer from this condition. This approach to the use of biomarker testing contrasts with other cardiovascular diagnoses such as acute myocardial infarction, for which biomarkers are integral to disease process definition, risk stratification, and in some cases treatment decision making.

CONTENT

In this review we consider various perspectives on the evaluation of biomarkers in HF. In addition, we examine recent advances in the understanding of established biomarkers in HF (such as the natriuretic peptides), the elucidation of novel biomarkers potentially useful for the evaluation and management of patients with HF, and the growing understanding of important and relevant comorbidities in HF. We also review candidate biomarkers from a number of classes: (a) myocyte stretch, (b) myocyte necrosis, (c) systemic inflammation, (d) oxidative stress, (e) extracellular matrix turnover, (f) neurohormones, and (g) biomarkers of extracardiac processes, such as renal function.

SUMMARY

Novel applications of established biomarkers of HF as well as elucidation and validation of emerging assays for HF syndromes have collectively led to a growing interest in the more widespread use of such testing in patients affected by the diagnosis.

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

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