Plasma vasoactive peptides after acute myocardial infarction in relation to left ventricular dysfunction

Natriuretic peptides in acute coronary syndromes: A new role to predict recurrent ischemic event-related mortality?

Risk stratification in acute coronary syndromes (ACS) has been previously based on the severity of acute clinical presentation, presence of cardiovascular comorbidities, and abnormalities of ischemia-specific biomarkers, most importantly troponins. Natriuretic peptides (NPs), which become elevated upon increased myocardial wall stress, are established diagnostic and prognostic biomarkers in patients with heart failure. Recently, their prognostic potential in ACS has been reported, specifically as predictors of future new-onset heart failure or left ventricular (LV) systolic dysfunction. In the current issue of the Hellenic Journal of Cardiology, a new role of NPs is suggested in ACS as predictors of long-term mortality associated with recurrent cardiac ischemic events, specifically in patients with preserved or mid-range LV ejection fraction upon index ACS. Potential pathophysiological mechanisms that explain the association between augmented NP levels with recurrent myocardial ischemia are hypothesized including the potential of NPs to reflect augmented local and/or systemic inflammation, prothrombotic state, and vascular dysregulation.

Post-myocardial infarction intraventricular conduction defects and B-type natriuretic peptide levels

BACKGROUND

Levels of B-type natriuretic peptide (BNP), a significant marker of left ventricular (LV) dysfunction, may provide information on the severity of heart failure in patients with intraventricular conduction defects (IVCD).The aim of this study was to measure serum BNP levels in post-myocardial infarction (MI) patients with IVCD.

METHODS

In 2004-2005 during standard follow-up at 6 mo after acute MI in 158 subjects, BNP was measured using an immunoenzymatic method. Of them, 126 patients had IVCD: 31, left bundle branch block (LBBB); 36, right bundle branch block (RBBB); 30, left anterior hemiblock (LAH); and 29, left posterior hemiblock (LPH). Thirty two patients with a previous MI, but without IVCD, served as controls, whereas 15 healthy subjects entered the comparative group.

RESULTS

In post-MI patients with IVCD, the mean BNP level was significantly higher than in their counterparts without IVCD (p < 0.001) and in healthy subjects (p < 0.001). The highest BNP level was found in patients with LBBB and RBBB. In patients with LAH and LPH, levels of BNP were insignificantly higher than in patients without IVCD.

CONCLUSIONS

Significantly higher BNP levels in patients with previous MI and IVCD suggest more severe heart failure than in their counterparts without IVCD with comparable LV ejection fraction.

The Biologic Variability of B-Type Natriuretic Peptide and N-Terminal Pro-B-Type Natriuretic Peptide in Stable Heart Failure Patients

BACKGROUND

There are conflicting data on the usefulness of B-type natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) in the optimization of therapy for heart failure (HF). Discordant results may be explained by the intra-individual variability of these peptides. This study evaluates the intraindividual variability of BNP and NT-proBNP and the impact of the covariates of age, sex, and renal function.

METHODS AND RESULTS

Stable HF patients attending our unit were included. Blood samples were drawn 1 hour apart on 2 occasions 1 week apart. Forty-five patients were enrolled (69.6 +/- 12.1 years, 64% male, 84% systolic HF). Within-hour and within-week intraindividual variability were: 6.9% and 21.1% for NT-proBNP; 14.6% and 28.4% for BNP (P < .01 for within-hour comparison of BNP and NT-proBNP). Reference change values over 1 week for NT-proBNP and BNP were 49.2% and 66.2%, respectively. There were no significant relationships identified between variability and age, gender, or glomerular filtration rate.

CONCLUSION

There is considerable intraindividual variability in these peptides in stable HF patients. Changes of approximately 50% and 66% for NT-proBNP and BNP from week to week are needed to indicate an altered clinical status and caution should be exercised in interpreting serial changes in these peptide levels when monitoring patient responses to treatment or clinical status.

Serum NT-proBNP concentrations in the early phase do not predict the severity of systolic or diastolic left ventricular dysfunction among patients with ST-elevation acute myocardial infarction

The cohort included 55 consecutive patients with first ST elevation acute myocardial infarction (STEAMI) who underwent reperfusion. Blood samples were drawn for N-terminal pro B-type natriuretic peptide (NT-proBNP), highly-sensitive C-reactive protein (hs-CRP), creatinine kinase (CK), cardiac troponin l (cTnl), and white blood cell (WBC) count within 24 hours of admission. Transthoracic echocardiography, performed within the same time frame, assessed left ventricular (LV) systolic function, as well as diastolic function. Variables significantly associated with poor systolic LV dysfunction were hs-CRP, peak CK, cTnl, and WBC. There was no significant correlation between NT-proBNP and systolic function early after STEAMI (p=0.49). Among patients with diastolic dysfunction, there was no significant correlation between NT-proBNP levels and peak mitral E-wave velocity to peak initial A-wave velocity (E/A ratio) (r =0.19, p=0.18) or E-wave deceleration time (r =0.22, p=0.15). Thus, NT-proBNP levels in the early phase after STEAMI were not indicative of systolic or diastolic function.

[The role of B type natriuretic peptide in the assessment of post myocardial infarction prognosis]

Recently cardiac peptides have received close attention as cardiovascular markers. Brain (B type) natriuretic peptide is a neurohormone synthesized predominantly in ventricular myocardium. Previous studies have shown that this hormone can provide prognostic information in patients with myocardial infarction. The aim of this review is to evaluate the impact of plasma levels of BNP on prediction of left ventricular ejection fraction and remodelling and major cardiac events after myocardial infarction.

Rise and fall of B-type natriuretic peptide levels in patients with coronary artery disease and normal left ventricular function after cardiac revascularization

BACKGROUND

Recently, it was shown that B-type natriuretic peptide levels are increased in patients with acute coronary syndromes.

AIMS

To assess the relation between B-type natriuretic peptide and ischemia in patients with stable and unstable angina pectoris with normal left ventricular function in relation to the extent of ischemia and response to revascularization.

METHODS

Fifty-nine consecutive patients were enrolled in the study, patients were divided into two groups: stable angina patients (group I, n=18), and unstable coronary patients (group II, n=41). Baseline characteristics were compared with 15 age-matched and sex-matched participants. B-type natriuretic peptide levels were measured at baseline and 3, 7 and 90 days after coronary revascularization in group I and II.

RESULTS

Patients with unstable angina pectoris had increased B-type natriuretic peptide levels compared with stable angina pectoris patients (B-type natriuretic peptide levels: controls 15.5+/-13 pg/ml, stable angina pectoris group 28.4+/-19 pg/ml, unstable angina pectoris group 104+/-81 pg/ml; P<0.01). A relationship between the number of affected coronary vessels and B-type natriuretic peptide was assessed (one-vessel 29.9+/-21 pg/ml, two-vessel 93.8+/-87 pg/ml, three-vessel 119+/-88 pg/ml; P<0.01). After revascularization, B-type natriuretic peptide levels decreased in groups I and II (25+/-20 vs. 39+/-28 pg/ml) and were similar after 90 days in percutaneous transluminal coronary angiograghy and in coronary artery bypass grafting groups (percutaneous transluminal coronary angiography 26+/-22 pg/ml, coronary artery bypass grafting 36+/-26 pg/ml; NS).

CONCLUSIONS

B-type natriuretic peptide levels increase in unstable angina pectoris patients and are linked to the extent of coronary disease in patients with normal left ventricular systolic function, and returned to baseline level after surgical or catheter revascularization.

Plasma B-type natriuretic peptide reflects left ventricular hypertrophy and diastolic function in hypertension

BACKGROUND

Hypertension is associated with changes in concentrations of vasoactive peptides and procollagen propeptides, but their relationships with left ventricular hypertrophy and cardiac function are unclear.

METHODS

We measured plasma levels of atrial natriuretic peptide (ANP), its amino terminal propeptide (NT-proANP), B-type natriuretic peptide (BNP), endothelin-1 (ET-1), and serum levels of the aminoterminal propeptide of type I procollagen (PINP) and the aminoterminal propeptide of type III procollagen (PIIINP) and echocardiographic parameters in 97 patients with hypertension in the Anglo-Scandinavian Cardiac Outcomes Trial.

RESULTS

Median values (reference values) of the peptides were: ANP 11.2 (6.9-14.9) pmol/l, NT-proANP 351 (143-311) pmol/l, BNP 1.1 (0.4-7.2) pmol/l, ET-1 8.7 (1.2-5.0) pmol/l, PIIINP 2.8 (1.7-4.2) microg/l and PINP 29 (19-84) microg/l. Plasma BNP levels in patients with left ventricular hypertrophy (1.2 pmol/l) and patients with echocardiographic signs of diastolic dysfunction (1.5 pmol/l) were greater than those in patients without hypertrophy (0.7 pmol/l) and normal diastolic parameters (0.9 pmol/l) (p<0.05). BNP was the only biochemical parameter that independently predicted interventricular septal diastolic diameter (p<0.05), left ventricular mass index (p<0.01) and ratio of the velocity-time integrals of the E and A waves of the mitral inflow in a stepwise logistic regression analysis (p<0.05).

CONCLUSIONS

The results show that BNP reflects the remodelling process in hypertension.

Molecular Heterogeneity Has a Major Impact on the Measurement of Circulating N-Terminal Fragments of A- and B-Type Natriuretic Peptides

Background: The N-terminal fragments of A- and B-type natriuretic peptides (NT-proANP and NT-proBNP) are powerful markers of cardiac function. The current assays require refinement with regard to standardization with native calibrators and the ability to detect the actual circulating forms.

Methods: The following peptides were prepared with recombinant methods: NT-proANP, NT-proBNP, proBNP1–108, and Tyr0-proBNP77–108. Fifteen peptides of 13–22 amino acids, spanning the sequences of NT-proANP and NT-proBNP, were prepared by solid-phase peptide synthesis. Two immunoassays for NT-proANP and four for NT-proBNP were set up, each with a different epitope specificity. The assays were applied for the measurement of NT-proANP and NT-proBNP in healthy individuals and in patients with acute myocardial infarction. The circulating molecular forms were analyzed by gel-filtration and reversed-phase HPLC.

Results: According to the HPLC analyses, circulating NT-proANP consists mainly of the full-length peptide, with some degradation at both ends. In contrast, circulating NT-proBNP is very heterogeneous. Most immunoreactive NT-proBNP is significantly smaller in size than NT-proBNP1–76, with truncation at both termini. The smallest fragments can be detected by assays directed at the central part of NT-proBNP only; assays directed at the ends gave 30–40% lower values. Despite the difference, the various assays correlated reasonably well with each other (r2 = 0.77–0.85). In patients with acute myocardial infarction, NT-proANP and NT-proBNP concentrations were 1.8–2.3 and 4.2–4.5 times higher than in healthy individuals. The development of heart failure further increased the concentrations.

Conclusions: Molecular heterogeneity of the circulating forms causes a serious risk of preanalytical errors in assays for NT-proBNP and, to a lesser extent, NT-proANP. The development of a sandwich assay for NT-proBNP would be especially challenging. The most robust and reliable assays use antibodies directed at the central portions of NT-proANP or NT-proBNP.

Atrial natriuretic peptide, B-type natriuretic peptide, and serum collagen markers after acute myocardial infarction

Experimental data suggest that atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) act locally as antifibrotic factors in heart. We investigated the interrelationships of natriuretic peptides and collagen markers in 93 patients receiving thrombolytic treatment for their first acute myocardial infarction (AMI). Collagen formation following AMI, evaluated as serum levels of amino terminal propeptide of type III procollagen, correlated with NH2-terminal proANP ( r = 0.45, P < 0.001), BNP ( r = 0.55, P < 0.001) and NH2-terminal proBNP ( r = 0.50, P < 0.01) on day 4 after thrombolysis. Levels of intact amino terminal propeptide of type I procollagen decreased by 34% ( P < 0.001), and levels of carboxy terminal cross-linked telopeptide of type I collagen (ICTP) increased by 65% ( P < 0.001). ICTP levels correlated with NH2-terminal proBNP ( r = 0.25, P < 0.05) and BNP ( r = 0.28, P < 0.05) on day 4. Our results suggest that ANP and BNP may act as regulators of collagen scar formation and left ventricular remodeling after AMI in humans. Furthermore, degradation of type I collagen is increased after AMI and may be regulated by BNP.

Brain natriuretic peptide levels during cardiac reperfusion: comparison between percutaneous coronary angioplasty and aorto-coronaric bypass

BACKGROUND

Several studies have documented brain natriuretic peptide (BNP) behavior during cardiac ischemia and after myocardial necrosis. Peptide levels have been shown to be increased during acute phase of cardiac ischemia and during late ventricular remodelling; however, there are fewer data about hormone levels during percutaneous transluminal coronary angioplasty (PTCA) and aorto-coronaric by pass (CABG).

METHODS

Aim of this study was to investigate plasma BNP during acute or sub-acute myocardial ischemia in patients undergoing to PTCA or CABG, taking blood samples before and after both procedures. We studied 59 consecutive subjects, 25 submitted to coronary by-pass and 34 submitted to coronary angioplasty. Blood BNP levels were measured the day before intervention and after 3, 7 and 90 days from the procedures.

RESULTS

Peptide levels were significantly different just before intervention (GABG group 118.7+/-81 pg/ml vs. PTCA group 34.8+/-15 pg/ml, p<0.01). This difference was increased after 3 days (CABG group 403.2+/-185 pg/ml vs. PTCA group 105.3+/-56 pg/ml, p<0.0001) and after 7 days (CABG group 252.2+/-93 pg/ml vs. PTCA group 69.8+/-36 pg/ml, p<0.00001). These results trend to converge after 90 days (CABG group +/-93 pg/ml vs. PTCA group +/-36 pg/ml, p<0.05).

CONCLUSIONS

Plasma BNP shows a different behavior during and after different myocardial reperfusion procedures. PTCA causes only mild and temporary elevation of peptide levels, otherwise CABG demonstrates a more enhancing of BNP release not only in early phase but also after one week; increased levels tend to return towards the reference range after few weeks from cardiac surgery.

Diagnostic accuracy and prognostic relevance of the measurement of cardiac natriuretic peptides: a review

BACKGROUND

The pathophysiologic and clinical relevance of cardiac natriuretic hormone (CNH) assays has been investigated in numerous experimental and clinical studies. Authors have sought to evaluate the diagnostic accuracy and prognostic relevance of the measurement of CNHs according to evidence-based laboratory medicine principles.

METHODS

In June 2003, we ran a computerized literature search on National Library of Medicine using keywords "ANP" and "BNP" and found more than 12 300 and 1200 articles, respectively. A more refined search with keywords "ANP or BNP assay" extracted approximately 7000 and 800 articles, respectively. Only studies specifically designed to evaluate the diagnostic accuracy and prognostic relevance of CNH measurements were selected from this huge mass of articles to be discussed in this review.

CONTENT

Several studies suggested that CNH assays may be clinically useful for the screening and classification of patients with heart failure, as a prognostic marker in cardiovascular disease, in the follow-up of patients with heart failure, and because they may reduce the need for further cardiac investigation. However, it is difficult to compare even the best-designed studies because not only did the authors evaluate different populations, they also used different gold standards.

CONCLUSIONS

CNH assays and conventional diagnostic work-ups provide complementary information for evaluation of the presence and severity of cardiac dysfunction and clinical disease. Several aspects of CNH assays are still to be elucidated, and further work is needed to carefully assess their diagnostic accuracy and prognostic value in cardiac disease.

Cardiac hormones as diagnostic tools in heart failure

In patients with heart failure, plasma levels of atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP), and the N-terminal fragments of their prohormones (N-ANP and N-BNP) are elevated, because the cardiac hormonal system is activated by increased wall stretch due to increased volume and pressure overload. Patients suspected of having heart failure can be selected for further investigations on the basis of having an elevated plasma concentration of N-ANP, BNP, and N-BNP. High levels of cardiac hormones identify those at greatest risk for future serious cardiovascular events. Moreover, adjusting heart failure treatment to reduce plasma levels of N-BNP may improve outcome. Cardiac hormones are most useful clinically as a rule-out test. In acutely symptomatic patients, a very high negative predictive value is coupled with a relatively high positive predictive value. Measurement of cardiac hormones in patients with heart failure may reduce the need for hospitalizations and for more expensive investigations such as echocardiography. However, there have also been conflicting reports on the diagnostic value of cardiac hormones, they are not specific for any disease, and the magnitude of the effects of age and gender on BNP in the normal subgroup suggests that these parameters need to be considered when interpreting cardiac hormone levels.

Natriuretic peptides in the diagnosis of heart disease--first amongst equals?

The natriuretic peptides and their role in neurohumoral regulation of the cardiovascular system have become the focus of considerable interest from the scientific and clinical community in recent years. BNP in particular has been shown to be an important diagnostic and prognostic marker of use in a wide range of applications. As measurement techniques develop and are refined, routine evaluation of serum levels of these markers is expected to become more widespread. We have reviewed the biochemistry of the natriuretic peptide family, their role in cardiovascular pathophysiology and the evidence supporting their use in the clinical setting.

Differential regulation of atrial and brain natriuretic peptides and its implications for the management of left ventricular volume overload

BACKGROUND

In this study, we investigated the possibility that the atrial and brain natriuretic peptide expression in left ventricular volume overload (VOL) is transcriptionally regulated. We further evaluated the diagnostic and/or prognostic potential of this expression for the management of patients with this disorder.

DESIGN

We compared the myocardial mRNA expression and plasma levels of the two peptides in VOL patients using donor hearts and in healthy blood donors as controls.

RESULTS

The atrial natriuretic peptide (ANP) mRNA was elevated by 38% (P < 0.03) in the right atrium and by 53% (P < 0.003) in the left atrium, but was unchanged in the ventricular chambers of the patient group (n = 19) compared with controls (n = 8). Plasma ANP concentration was elevated by 62% (P < 0.001) compared with blood donor controls (n = 79). It increased slightly (by 36%) 2 h following surgery, and remained at 64% higher (P < 0.03 vs. presurgery) for the 5 days following surgery. The brain natriuretic peptide (BNP) mRNA was elevated by approximately one-fold in both the left ventricle (P < 0.02) and right atrium (P < 0.05), by 94% (P < 0.02) in the right ventricle and by 89% (P < 0.05) in the left atrium. Its plasma level in the patients was 3.4-fold (P < 0.00003) higher than in control subjects. It increased significantly by 1.2-fold (P < 0.01) 2 h following surgery, but dropped significantly (P < 0.05 vs. 2 h post surgery) to presurgical levels 5 days following surgery.

CONCLUSION

The results show chamber-specific elevation in both atrial and brain natriuretic peptide expression and differences in their circulating levels in VOL, suggesting that BNP is a potential prognostic indicator in the postsurgical management of these patients.

Natriuretic peptide system in fetal heart and circulation

Atrial natriuretic peptide, brain natriuretic peptide and C-type natriuretic peptide belong to a family of hormones that have diuretic, natriuretic and vasodepressor activity and play a part in pressure and volume homeostasis in adults. As little is known about the natriuretic peptides during cardiac maturation, this review summarizes current knowledge about the early expression of components of the natriuretic peptide system in the heart during embryonic and fetal development. The data indicate a functional importance of the fetal natriuretic peptide system, especially under pathophysiological conditions. Thus, in the fetus, the system fulfils important beneficial compensatory roles in cardiovascular disease, rather than in day-to-day pressure and volume homeostasis. In comparison with data on the relevance of natriuretic peptides in adults, those summarized here indicate a functional maturation of the natriuretic peptide system during ontogeny in mammals.

BNP and congestive heart failure

Brain natriuretic peptide (BNP), a peptide hormone secreted chiefly by ventricular myocytes, plays a key role in volume homeostasis. The plasma concentration of BNP is raised in various pathological states, especially heart failure. Many studies suggest that measurement of plasma BNP has clinical utility for excluding a diagnosis of heart failure in patients with dyspnea or fluid retention and for providing prognostic information in those with heart failure or other cardiac disease. It may also be of value in identifying patients after myocardial infarction in whom further assessment of cardiac function is likely to be worthwhile. Preliminary evidence suggests that measuring the plasma concentration of BNP may be useful in fine tuning therapy for heart failure. Artificially raising the circulating levels of BNP shows considerable promise as a treatment for heart failure. With simpler assay methods now available, it is likely that many physicians will measure plasma BNP to aid them in the diagnosis, risk stratification, and monitoring of their patients with heart failure or other cardiac dysfunction.

Neurohormonal activation in heart failure after acute myocardial infarction treated with beta-receptor antagonists

BACKGROUND

Few studies have described how neurohormonal activation is influenced by treatment with beta-receptor antagonists in patients with heart failure after acute myocardial infarction. The aims were to describe neurohormonal activity in relation to other variables and to investigate treatment effects of a beta(1) receptor-antagonist compared to a partial beta(1) receptor-agonist.

METHODS

Double-blind, randomized comparison of metoprolol 50-100 mg b.i.d. (n=74), and xamoterol 100-200 mg b.i.d (n=67). Catecholamines, neuropeptide Y-like immunoreactivity (NPY-LI), renin activity, and N-terminal pro-atrial natriuretic factor (N-ANF) were measured in venous plasma before discharge and after 3 months. Clinical and echocardiographic variables were assessed.

RESULTS

N-ANF showed the closest correlations to clinical and echocardiographic measures of heart failure severity, e.g. NYHA functional class, furosemide dose, exercise tolerance, systolic and diastolic function. Plasma norepinephrine, dopamine and renin activity decreased after 3 months on both treatments, in contrast to a small increase in NPY-LI which was greater (by 3.9 pmol/l, 95% CI 1.2-6.6) in the metoprolol group. N-ANF increased on metoprolol, and decreased on xamoterol (difference: 408 pmol/l, 95% CI 209-607). Increase above median of NPY-LI (>25.2 pmol/l, odds ratio 2.8, P=0.0050) and N-ANF (>1043 pmol/l, odds ratio 2.8, P=0.0055) were related to long term (mean follow-up 6.8 years) cardiovascular mortality.

CONCLUSIONS

Decreased neurohormonal activity, reflecting both the sympathetic nervous system and the renin-angiotensin system, was found 3 months after an acute myocardial infarction with heart failure treated with beta-receptor antagonists. The small increase in NPY-LI may suggest increased sympathetic activity or reduced clearance from plasma. The observed changes of N-ANF may be explained by changes in cardiac preload, renal function, and differences in beta-receptor mediated inhibition of atrial release of N-ANF. NPY-LI, and N-ANF at discharge were related to long term cardiovascular mortality.

Pro-atrial natriuretic peptide hormone from right atria is correlated with cardiac depression in septic patients

N-terminal pro-atrial natriuretic peptide [proANP(1-98)] has been extensively investigated in patients with chronic heart failure and ishemic heart disease. It is found to be a better marker of cardiac dysfunction than atrial natriuretic peptide (ANP). The possible involvement of proANP(1-98) in cardiac depression caused by sepsis has not been studied yet. Therefore, we analyzed atrial plasma concentration of proANP(1-98) in 17 septic patients with hemodynamic variables measured or calculated using pulmonary artery catheter. The results of altogether 96 measurements show a significant negative correlation of proANP(1-98) and cardiac index (p<0.024), oxygen delivery (p<0.03) and oxygen consumption (p<0.03). There is also a positive correlation with pulmonary vascular resistance (p<0.03). ProANP(1-98) is significantly higher in patients who developed acute respiratory distress syndrome (ARDS) (p<0.001). This study implies that proANP(1-98) is a possible novel hormone marker of cardiac depression caused by sepsis that could be used for prediction of ARDS.

Early expression of natriuretic peptides and SERCA in mild heart failure: association with severity of the disease

BACKGROUND

We investigated changes in genetic expression of atrial and brain natriuretic peptides (ANP and BNP) and sarcoplasmic reticulum Ca(2+)-ATPase (SERCA) in patients with stable mild to moderate chronic heart failure (CHF), since data on this topic were primarily obtained in end-stage CHF.

METHODS

We studied tissue from 25 patients with idiopathic dilated cardiomyopathy (IDC) in New York Heart Association (NYHA) class II (n=12) and III-IV (n=13). Myocardial tissue from normal hearts (n=10) served as controls. Messenger RNA (mRNA) expression of ANP, BNP, and SERCA was isolated, and correlated with severity of CHF, left ventricular function (LVEF), peak oxygen uptake (peak VO(2)), and wedge pressure.

RESULTS

A significant trend for gradual changes in mRNA expression according to increasing NYHA class was found for ANP, BNP (P<0.0001) and SERCA (P=0.04), with a marked increase in patients with more advanced CHF (ANP and BNP: P<0.01 vs. controls; SERCA: NS) and less pronounced changes in patients with mild CHF. mRNA of ANP and BNP correlated strongly with LVEF (-0.621 and -0.621, respectively, both P<0.01) and peak VO(2) (-0.625 and -0.555, respectively, both P<0.01) and, to a lesser extent, with wedge pressure (0.440 and 0.488, respectively, both P<0.05). SERCA correlated most strongly with wedge pressure (-0.623, P<0.01), and weak, non-significant correlations with LVEF and peak VO(2) were found.

CONCLUSIONS

Genetic expression of ANP, BNP, and SERCA is progressively altered in proportion to the severity of CHF, although this is more marked for ANP and to a lesser extent BNP, than for SERCA. These changes support the concept that already early in CHF, genetic expression is affected, which has implications for the understanding of the pathophysiology of CHF.

Plasma and pericardial fluid natriuretic peptide levels in postinfarction ventricular dysfunction

AIMS

In the present study we examined plasma and pericardial fluid ANP and BNP concentrations in postinfarction ventricular dysfunction. The association of peptide levels to left ventricular (LV) dysfunction and to the localization of the myocardial infarction (MI) was studied.

METHODS AND RESULTS

Plasma and pericardial fluid samples were obtained from 37 patients undergoing coronary bypass surgery. According to the ECG and preceding coronary angiography, the patients were divided into three groups: previous anterior myocardial infarction (MI) (n=12), previous inferior/posterior MI (n=15) and no history of MI (n=10). When compared to the control group with no MI, the patients with anterior MI had elevated plasma ANP and BNP (134+/-13 vs. 81+/-15 pg/ml, P<0.01 and 95+/-10 pg/ml vs. 26+/-8 pg/ml, P<0.01, respectively) and pericardial fluid BNP (473+/-60 pg/ml vs. 57+/-8 pg/ml, P<0.001) levels. The plasma natriuretic peptide concentrations were not increased in the patients with inferior/posterior MI, but the pericardial fluid BNP concentrations were greater than in the patients with no history of MI (129+/-35 pg/ml vs. 57+/-8 pg/ml, P<0.05). Six of the 12 patients with previous anterior MI had LVEF> or =45%. Despite their normal LV systolic function, these patients had increased plasma and pericardial fluid BNP levels when compared to the group with no history of MI (68+/-18 pg/ml vs. 26+/-8 pg/ml, P<0.05 and 534+/-258 pg/ml vs. 57+/-8 pg/ml, P<0.01, respectively).

CONCLUSIONS

Previous anterior myocardial infarction was associated with increased cardiac BNP production even if the LV systolic function was normal (LVEF> or =45%). The high pericardial fluid BNP concentrations in postinfarction patients suggest that the BNP synthesis and release are augmented in the ventricular myocardium independent from the LVEF.

Measurement of Cardiac Natriuretic Hormones (Atrial Natriuretic Peptide, Brain Natriuretic Peptide, and Related Peptides) in Clinical Practice: The Need for a New Generation of Immunoassay Methods

Background: Cardiac natriuretic hormones (CNHs) are a family of related peptides, including atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and other peptides derived from the N-terminal portion of the proANP and proBNP peptide chains. Assays for cardiac natriuretic peptides have been proposed to help assess clinical conditions associated with expanded fluid volume. In particular, the assays can be useful for distinguishing healthy subjects from patients in different stages of heart failure. Measurements of these hormones have also been considered for prognostic indicators of long-term survival in patients with heart failure and/or after acute myocardial infarction. The different CNHs differ in their production/secretion patterns and have different clearance rates. Furthermore, there are numerous proposed assay configurations for each of these hormones, and it is not clear which assay provides the best pathophysiological and/or clinical information.

Approach: Here we review recent studies concerning the competitive (such as RIA, enzyme immunoassay, or luminescence immunoassay) and noncompetitive immunoassays (such as two-site IRMA, ELISA, or immunoluminometric assay) for the different cardiac natriuretic peptides to compare the analytical characteristics and clinical relevance of assays for the different CNHs and the different assay formats.

Content: Developing sensitive, precise, and accurate immunoassays for cardiac natriuretic peptides has been difficult because of their low concentrations (on average, ∼3–6 pmol/L) in healthy subjects and because of their structural, metabolic, and physiological characteristics. Competitive assays have historically suffered from lack of sensitivity and specificity for the biologically active peptides. These usually require tedious extraction procedures prior to analysis. Recently, immunometric assays have been developed that have improved sensitivity and specificity; it appears these will be the methods of choice.

Summary: To date, there is no consensus on the best assay procedure of cardiac natriuretic peptides. To facilitate widespread propagation of determination of these hormones in routine clinical practice, it will be necessary to study the new generation of noncompetitive immunometric methods that are less time-consuming and more sensitive and specific. Although several studies suggest that BNP exhibits better clinical utility than the other CNHs, more studies examining multiple CNHs in the same cohorts of patients will be necessary.