The ease of use and reproducibility of the Alere™ Heart Check System: a comparison of patient and healthcare professional measurement of BNP

The role of non-invasive devices for the telemonitoring of heart failure patients

Heart failure (HF) patients represent one of the most prevalent as well as one of the most fragile population encountered in the cardiology and internal medicine departments nowadays. Estimated to account for around 26 million people worldwide, diagnosed patients present a poor prognosis and quality of life with a clinical history accompanied by repeated hospital admissions caused by an exacerbation of their chronic condition. The frequent hospitalizations and the extended hospital stays mean an extremely high economic burden for healthcare institutions. Meanwhile, the number of chronically diseased and elderly patients is continuously rising, and a lack of specialized physicians is evident. To cope with this health emergency, more efficient strategies for patient management, more accurate diagnostic tools, and more efficient preventive plans are needed. In recent years, telemonitoring has been introduced as the potential answer to solve such needs. Different methodologies and devices have been progressively investigated for effective home monitoring of cardiologic patients. Invasive hemodynamic devices, such as CardioMEMS™, have been demonstrated to be reducing hospitalizations and mortality, but their use is however restricted to limited cases. The role of external non-invasive devices for remote patient monitoring, instead, is yet to be clarified. In this review, we summarized the most relevant studies and devices that, by utilizing non-invasive telemonitoring, demonstrated whether beneficial effects in the management of HF patients were effective.

BNP/NT-proBNP in pulmonary arterial hypertension: time for point-of-care testing?

Despite the advent of new therapies and improved outcomes in patients with pulmonary arterial hypertension (PAH), it remains a life-shortening disease and the time to diagnosis remains unchanged. Strategies to improve outcomes are therefore currently focused on earlier diagnosis and a treatment approach aimed at moving patients with PAH into a category of low-risk of 1-year mortality. B-type natriuretic peptide (BNP; or brain natriuretic peptide) and N-terminal prohormone of BNP (NT-proBNP) are released from cardiac myocytes in response to mechanical load and wall stress. Elevated levels of BNP and NT-proBNP are incorporated into several PAH risk stratification tools and screening algorithms to aid diagnosis of systemic sclerosis. We have undertaken a systematic review of the literature with respect to the use of BNP and NT-proBNP in PAH and the use of these biomarkers in the diagnosis and risk stratification of PAH, their relation to pulmonary haemodynamics and the potential for point-of-care testing to improve diagnosis and prognosis.

Synthesis, secretion, function, metabolism and application of natriuretic peptides in heart failure

As a family of hormones with pleiotropic effects, natriuretic peptide (NP) system includes atrial NP (ANP), B-type NP (BNP), C-type NP (CNP), dendroaspis NP and urodilatin, with NP receptor-A (guanylate cyclase-A), NP receptor-B (guanylate cyclase-B) and NP receptor-C (clearance receptor). These peptides are genetically distinct, but structurally and functionally related for regulating circulatory homeostasis in vertebrates. In humans, ANP and BNP are encoded by NP precursor A (NPPA) and NPPB genes on chromosome 1, whereas CNP is encoded by NPPC on chromosome 2. NPs are synthesized and secreted through certain mechanisms by cardiomyocytes, fibroblasts, endotheliocytes, immune cells (neutrophils, T-cells and macrophages) and immature cells (embryonic stem cells, muscle satellite cells and cardiac precursor cells). They are mainly produced by cardiovascular, brain and renal tissues in response to wall stretch and other causes. NPs provide natriuresis, diuresis, vasodilation, antiproliferation, antihypertrophy, antifibrosis and other cardiometabolic protection. NPs represent body's own antihypertensive system, and provide compensatory protection to counterbalance vasoconstrictor-mitogenic-sodium retaining hormones, released by renin-angiotensin-aldosterone system (RAAS) and sympathetic nervous system (SNS). NPs play central roles in regulation of heart failure (HF), and are inactivated through not only NP receptor-C, but also neutral endopeptidase (NEP), dipeptidyl peptidase-4 and insulin degrading enzyme. Both BNP and N-terminal proBNP are useful biomarkers to not only make the diagnosis and assess the severity of HF, but also guide the therapy and predict the prognosis in patients with HF. Current NP-augmenting strategies include the synthesis of NPs or agonists to increase NP bioactivity and inhibition of NEP to reduce NP breakdown. Nesiritide has been established as an available therapy, and angiotensin receptor blocker NEP inhibitor (ARNI, LCZ696) has obtained extremely encouraging results with decreased morbidity and mortality. Novel pharmacological approaches based on NPs may promote a therapeutic shift from suppressing the RAAS and SNS to re-balancing neuroendocrine dysregulation in patients with HF. The current review discussed the synthesis, secretion, function and metabolism of NPs, and their diagnostic, therapeutic and prognostic values in HF.

A systematic evaluation of immunoassay point-of-care testing to define impact on patients' outcomes

Background Point-of-care testing has been developed to provide rapid test results. Most published studies focus on analytical performance, neglecting its impact on patient outcomes. Objective To review the analytical performance and accuracy of point-of-care testing specifically planned for immunoassay and to evaluate the impact of faster results on patient management. Methods A search of electronic databases for studies reporting immunoassay results obtained in both point-of-care testing and central laboratory scenarios was performed. Data were extracted concerning the study details, and the methodological quality was assessed. The analytical characteristics and diagnostic accuracy of six points-of-care testing: troponin, procalcitonin, parathyroid hormone, brain natriuretic peptide, C-reactive protein and neutrophil gelatinase-associated lipocalin were evaluated. Results A total of 116 scientific papers were analysed. Studies measuring procalcitonin, parathyroid hormone and neutrophil gelatinase-associated lipocalin reported a limited impact on diagnostic decisions. Seven studies measuring C-reactive protein claimed a significant reduction of antibiotic prescription. Several authors evaluated brain natriuretic peptide or troponin reporting faster decision-making without any improvement in clinical outcome. Forty-four per cent of studies reported analytical data, showing satisfactory correlations between results obtained through point-of-care testing and central laboratory setting. Half of studies defined the diagnostic accuracy of point-of-care testing as acceptable for troponin (median sensitivity and specificity: 74% and 94%, respectively), brain natriuretic peptide (median sensitivity and specificity: 82% and 88%, respectively) and C-reactive protein (median sensitivity and specificity 85%). Conclusions Point-of-care testing immunoassay results seem to be reliable and accurate for troponin, brain natriuretic peptide and C-reactive protein. The satisfactory analytical performance, together with an excellent practicability, suggests that it could be a consistent tool in clinical practice, but data are lacking regarding the patient outcomes.

Measuring B-Type Natriuretic Peptide From Capillary Blood or Venous Sample: Is It the Same?

BACKGROUND

In recent years, several systems have been implemented to achieve quick and non-invasive measurements of B-type natriuretic peptide (BNP). Among them, Alere^TM Heart Check (AHC) BNP test represents the most recent advancement. It is a rapid point-of-care (POC) immunoassay, projected for measuring BNP directly from a capillary whole blood sample. This study aimed at comparing the analytical and clinical performances of this new POC to our reference method (Abbott Architect System).

METHODS

One hundred eleven patients with stable chronic heart failure (CHF) referring to one cardiac rehabilitation center were enrolled from December 2013 to May 2015. These patients were subjected to a simultaneous capillary (AHC) and plasma (Abbott) BNP measurements. Clinical and analytical performances of AHC were assessed and compared to the reference method.

RESULTS

Capillary BNP showed a good correlation with the reference method (r = 0.94, P < 0.0001), although the values diverged when BNP was higher than 1,500 pg/mL. Indeed, the AHC had a relatively poor precision and the coefficient of variability was 10.1% and 18% for low and high controls, respectively. However, both methods showed similar diagnostic performances in discriminating the patients with heart failure in New York Heart Association (NYHA) class I from those belonging to NYHA classes II-III, with values of area under the curve (AUC) of 0.983 and 0.984, respectively, and equivalent sensitivity, specificity, and positive and negative likelihood ratios.

CONCLUSION

The AHC BNP test is a good POC able to provide reliable information about the hemodynamic status of CHF patients, especially of those belonging to NYHA classes I-III.

Clinical evaluation of the Heart Check system, a new quantitative measurement of fresh capillary BNP

AIM

We have evaluated here the clinical and analytical performance of the Alere™ Heart Check (AHC) test, a rapid point-of-care immunoassay designed for the measurement of BNP from fresh capillary whole blood.

PATIENTS & METHODS

One-hundred-and-sixty-three patients with stable chronic heart failure followed at the cardiac rehabilitation were submitted to simultaneous capillary (AHC) and plasma (Abbott architect system) BNP measurements.

RESULTS

Both methods showed a good correlation, although the values diverged when BNP was higher than 2000 pg/ml. Despite a relatively poor precision of AHC, however, both methods showed the same performances to assess patients' dyspnea and equivalent sensitivity, specificity, negative and positive predicting values.

CONCLUSION

AHC BNP test is a good POC for the management of heart failure despite a relatively poor precision.

Effect of low-dose diuretics on the level of serum cystatin C and prognosis in patients with asymptomatic chronic heart failure

The aim of the present study was to investigate the effect of low-dose diuretics on the serum cystatin C (CysC) and serum creatinine (Scr) levels, and on the prognosis in patients with asymptomatic chronic heart failure (HF). A total of 66 asymptomatic chronic HF patients were divided into the observation and control groups (n=33 in each group). Patients in the control group were treated with a routine treatment, while the patients in the observation group were treated with the diuretic hydrochlorothiazide along with the same routine treatment as the control group. The left ventricular ejection fraction (LVEF), serum CysC levels, Scr levels, heart function, prognosis, adverse reactions and complications of the patients in the two groups were compared prior to and following treatment. The LVEF increased in the two groups following treatment, while the levels of serum CysC and Scr decreased. The LVEF in the observation group increased following treatment for 1, 3 and 6 months compared with the LVEF values in the control group. In addition, the levels of serum CysC and Scr in the observation group were found to be lower compared with those in the control group (P<0.05). The incidence of adverse prognosis following treatment for 6 months in the observation group was lower compared with that in the control group (P<0.05). The proportion of HF patients with New York Heart Association (NYHA) class I and II increased following treatment for 6 months in the two groups (P<0.05). However, in the observation group, a higher number of patients exhibited class I and II disease after treatment for 6 months compared with the number in the control group (P<0.05). Furthermore, no statistically significant difference was observed between adverse reactions and complications in the two groups (P>0.05). In conclusion, low-dose diuretics may effectively improve the cardiac and renal functions and prognosis in asymptomatic chronic HF patients, without increasing the incidence of side effects.