Plasma atrial natriuretic factor concentration during maximal cardiopulmonary exercise in men with mild heart failure

Natriuretic peptide response to dynamic exercise in patients with atrial fibrillation

BACKGROUND

In patients with atrial fibrillation (AF) information regarding exercise release of atrial natriuretic peptide (ANP) is sparse and data on plasma brain natriuretic peptide (BNP) response to exercise is lacking. The aim of this study was to investigate plasma ANP and BNP response to exercise in patients with permanent AF and to assess if the response was different from the response in healthy age- and sex-matched control subjects.

METHODS

Plasma venous concentrations of ANP and BNP were determined at rest, at peak exercise and 30 min from the end of exercise in 38 patients with permanent AF and in 43 age- and sex-matched healthy control subjects.

RESULTS

Plasma concentrations of ANP and BNP were significantly higher in AF patients compared with the healthy control group at rest, peak exercise and after 30 min of recovery (p<0.0001). ANP and BNP increased significantly during exercise in both patients with AF and in the healthy control subjects (p<0.05). The increase in plasma concentration of ANP and BNP during exercise was significantly higher in AF patients compared with healthy controls (p=0.0002 for ANP; p<0.0001 for BNP). In the recovery period plasma BNP decreased significantly (p<0.0001) where as the decrease in plasma ANP was insignificant (p=0.4).

CONCLUSIONS

Patients with permanent AF have elevated levels of ANP and BNP at rest and exhibit much higher exercise release compared to healthy control subjects. This enhanced secretion of potent vasodilating and natriuretic agents may represent an important compensatory mechanism to improve exercise capacity in patients with AF.

Hormonal responses to the 6-minute walk test in women and men with coronary heart disease: a pilot study

BACKGROUND

Women with coronary heart disease (CHD) are more likely than men to develop congestive heart failure (CHF). Dysregulation of sympathetic and volume-regulatory hormones may contribute to the onset of symptomatic CHF. We hypothesized that this hormonal dysregulation develops at an earlier stage of CHD in women than in men.

OBJECTIVES

The study goals were (1) to determine the effect of gender on basal and exercise-induced plasma concentrations of catecholamines and volume-regulatory hormones in patients diagnosed with CHD, New York Heart Association class I and (2) to determine efficacy of the 6-minute walk test as a stimulus for release of these hormones.

METHODS

Study participants were 9 women and 9 men with normal left ventricular ejection fraction (>50%) and CHD confirmed by arteriography. Data were collected under resting conditions, and after the 6-minute walk test, in the general clinical research center of a northeastern university medical center.

RESULTS

Basal plasma vasopressin (VP) concentration was significantly higher in men than in women (P = .018). Exercise, for women and men combined, significantly increased atrial natriuretic peptide (P < .0005), VP (P = .04), norepinephrine (P < .0005), and epinephrine (P = .038) but not plasma renin activity (P = .09). No further gender differences were detected for basal levels, or for the magnitude of exercise-induced increases, for any of the hormones measured.

CONCLUSIONS

The 6-minute walk test is an exercise of sufficient intensity and duration to initiate the release of hormones associated with sympathetic activation and fluid-electrolyte regulation in both women and men with CHD. It appears that a gender difference was detected only for basal VP levels.

Effect of exercise on natriuretic peptides in plasma and urine in chronic heart failure

BACKGROUND

Plasma atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are elevated in chronic heart failure (CHF). ANP is known to be increased during exercise in healthy subjects and CHF, while the response in BNP during exercise is less clear and does not exist in C-type natriuretic peptide (CNP) and aquaporin-2 (AQP2) in either healthy subjects or CHF.

METHODS

Eleven patients with CHF and eleven healthy subjects performed a maximal aerobic exercise test. ANP and BNP in plasma were determined every 3 min and at maximum exercise by radioimmunoassay (RIA) and CNP and AQP2 in urine were determined before and after the exercise test by RIA.

RESULTS

The absolute increase in BNP during exercise was higher in patients with CHF (CHF: 4.1 pmol/l; healthy subjects: 1.3 pmol/l, P<0.05) and was positively correlated to BNP at rest (P<0.05), while the absolute increase in ANP during exercise was the same in the two groups (CHF: 4.2 pmol/l; healthy subjects: 6.8 pmol/l, not significant, NS). In CHF, exercise did not change either u-CNP excretion (rest: 9.8 ng/mmol creatinine; after exercise: 8.8 ng/mmol, NS) or u-AQP2 (rest: 466 ng/mmol creatinine; after exercise: 517 ng/mmol creatinine, NS) as well as in healthy subjects where u-CNP (rest: 9.7 ng/mmol creatinine; after exercise: 9.2 ng/mmol creatinine) and u-AQP2 (rest: 283 ng/mmol creatinine; after exercise: 307 ng/mmol creatinine) were the same at rest and after exercise.

CONCLUSION

The absolute increase in BNP during exercise is higher in patients with CHF compared to healthy subjects. It is suggested that this is a compensatory phenomenon to improve the exercise capacity in CHF, and that BNP is a more important factor in cardiovascular homeostasis during exercise in CHF than ANP.

Augmented response in plasma brain natriuretic peptide to dynamic exercise in patients with left ventricular dysfunction and congestive heart failure

OBJECTIVES

We have previously demonstrated that patients with symptomatic congestive heart failure (CHF), but not with asymptomatic left ventricular dysfunction (LVD), have augmented plasma atrial natriuretic peptide (ANP) response to exercise. Plasma brain natriuretic peptide (BNP) response to exercise is less extensively studied. The aim of this study was to determine whether responses of plasma BNP during exercise normalized for exercise workload are altered in patients with LVD and CHF.

SUBJECTS AND METHODS

Twenty-nine patients with LVD, 32 patients with CHF (NYHA classes II-III) and 27 age-matched control subjects were studied. Ventilatory, plasma ANP and BNP responses were assessed during symptom-limited cardiopulmonary exercise testing. Plasma natriuretic peptide levels were measured at rest and immediately after peak exercise. The increment in plasma BNP was divided by the increment in oxygen uptake (VO2) from rest to peak exercise, and this ratio [BNP exercise ratio: (peak BNP - rest BNP)/(peak VO2 - rest VO2)] was compared amongst the three groups.

RESULTS

Peak VO2 (Control, LVD and CHF: 28.2 +/- 1.7, 21.1 +/- 1.8, 16.2 +/- 0.6 ml, min(-1) kg(-1), respectively), anaerobic threshold and peak workload became smaller as heart failure worsened. Resting and peak plasma ANP levels were significantly higher only in CHF, whilst resting and peak plasma BNP levels displayed a significant and continuous increase from normal subjects to LVD and CHF. The ANP exercise ratio (1.25 +/- 0.36, 2.61 +/- 0.57, 7.72 +/- 1.65, ANOVA P = 0.0002) was significantly higher only in patients with CHF, whilst the BNP exercise ratio (0.35 +/- 0.10, 2.60 +/- 0.69, 4.98 +/- 0.97, ANOVA P = 0.0001) was significantly higher in patients with LVD and became progressively higher in patients with CHF.

CONCLUSIONS

These data showed that the BNP exercise ratio, an exercise plasma BNP response normalized with exercise workload, was augmented in patients with LVD, and became progressively higher in CHF, suggesting that an augmented exercise BNP ratio exists early in the course of developing CHF.

Plasma levels of atrial natriuretic peptide and of other vasoconstricting hormones in patients with chronic heart failure: relationship to exercise capacity

We investigated the relationship between exercise capacity and the level of neurohormonal activation at rest and during exercise in patients with various degrees of severity of chronic heart failure. We performed exercise testing with measurements of peak oxygen consumption (pVo2) and blood sampling at rest and at peak exercise in eight patients with moderate heart failure (pVo2 = 17 +/- 0.4 ml/kg/min) (mean +/- S.E.M.) and eight patients with severe CHF (pVo2 = 9 +/- 1 ml/kg/min). None of the patients was taking angiotensin converting enzyme inhibitors or beta-blockers. Plasma levels of atrial natriuretic peptide, cGMP, arginine-vasopressin, renin, angiotensin II, epinephrine and norepinephrine increased significantly (P < 0.01), from rest to peak exercise, in all patients. Among all the studied neurohormonal factors, only atrial natriuretic peptide levels at rest as well as at peak exercise, in patients with severe heart failure were correlated significantly to pVo2 (r = -0.77, P = 0.04; r = -0.85, P = 0.01, respectively) and to exercise duration (r = -0.72, P = 0.05; r = -0.79; P = 0.03, respectively). The relationship between plasma levels of atrial natriuretic peptide and of cGMP was shifted downward in the more severe patients suggesting the loss of biological activity of atrial natriuretic peptide.

Plasma brain natriuretic peptide as an indicator of left ventricular systolic function and long-term survival after acute myocardial infarction. Comparison with plasma atrial natriuretic peptide and N-terminal proatrial natriuretic peptide

BACKGROUND

Elevated plasma levels of atrial natriuretic peptide (ANP) and the N-terminal fragment of the ANP prohormone (N-ANP) are associated with decreased left ventricular function and decreased long-term survival after acute myocardial infarction (AMI). Previous data suggest that plasma brain natriuretic peptide (BNP) may increase proportionally more than plasma ANP after AMI and in chronic heart failure. The diagnostic and prognostic value of plasma BNP as an indicator of left ventricular dysfunction and long-term survival after AMI, relative to that of ANP and N-ANP, remain to be established.

METHODS AND RESULTS

Venous blood samples for analysis of ANP, N-ANP, and BNP were obtained on day 3 after symptom onset from 131 patients with documented AMI. Left ventricular ejection fraction was determined by echocardiography in a subsample of 79 patients. Twenty-eight cardiovascular and 3 noncardiovascular deaths occurred during the follow-up period (median, 1293 days). All three peptides proved to be powerful predictors of cardiovascular mortality by univariate Cox proportional hazards regression analyses (ANP: P < .0001; N-ANP: P = .0002; BNP: P < .0001). In a multivariate model, plasma BNP (P = .021) but not ANP (P = .638) or N-ANP (P = .782) provided additional prognostic information beyond left ventricular ejection fraction. Logistic regression analysis showed that ANP (P = .003) and N-ANP (P = .027) but not BNP (P = .14) were significantly associated with a left ventricular ejection fraction < or = 45%.

CONCLUSIONS

These results suggest that plasma BNP determination provides important, independent prognostic information after AMI. Although plasma ANP appears to be a better predictor of left ventricular dysfunction, plasma BNP may have greater potential to complement standard prognostic indicators used in risk stratification after AMI because of its strong, independent association with long-term survival, enhanced in vitro stability, and simplicity of analysis.

Neurohumoral measurements as indicators of long-term prognosis after acute myocardial infarction

The objective of this study was to evaluate the prognostic accuracy and usefulness of neurohumoral determination as a risk stratification tool after acute myocardial infarction (AMI) by comparing the long-term prognostic value of subacute neurohumoral measurements with other established indicators of adverse outcome. The study included 145 patients with documented AMI. During a median follow-up of 3.7 years, 30 cardiovascular and 6 noncardiovascular deaths occurred. By univariate analysis, plasma atrial natriuretic factor (ANF) and endothelin levels were strongly related to long-term cardiovascular mortality. In multivariate models, both peptides added prognostic information to that obtained from clinical evaluation, but not to that obtained from left ventricular ejection fraction (LVEF). Estimation of the area under the receiver-operating characteristic curve showed comparable prognostic accuracy for LVEF (0.7788), plasma ANF (0.7795), plasma endothelin (0.7493), and Killip classification (0.8203), meaning that for all these prognostic indicators, a randomly selected patient from the group of patients dying will have a test value larger than that of a randomly selected patient from the group of surviving patients 75% to 82% of the time. The clinical usefulness of neurohumoral determination in routine risk stratification after AMI appears to be limited since no additional prognostic information to that provided by objective evaluation of LV systolic function is obtained. However, in patients for whom objective assessment of LV performance is not readily available, measurement of plasma ANF and endothelin may be helpful in identifying asymptomatic patients at risk for cardiac death.

Plasma endothelin determination as a prognostic indicator of 1-year mortality after acute myocardial infarction

BACKGROUND

Plasma endothelin concentrations are increased in the acute phase of myocardial infarction and in chronic heart failure. Since endothelin may contribute to hemodynamic deterioration by potent vasoconstrictory and cardiotoxic actions, increased plasma levels may be associated with an unfavorable prognosis after myocardial infarction.

METHODS AND RESULTS

We tested the hypothesis that plasma endothelin determination in the subacute phase of myocardial infarction is related to subsequent survival and assessed whether plasma endothelin measurements provide additional prognostic information to that obtained from clinical and biochemical variables previously known to be associated with high mortality. Plasma endothelin determination was obtained from 142 patients (average age +/- SD, 67.8 +/- 10.1 years) on day 3 after documented myocardial infarction and was related to 1-year mortality. Sixteen patients died during the follow-up period. In a univariate Cox proportional-hazards model, day 3 plasma endothelin concentrations were significantly related to mortality (P < .0001). Patient age, previous treatment for systemic hypertension, presence of clinical heart failure, and plasma atrial natriuretic factor levels were all related to mortality in univariate analysis but provided no additional prognostic information to that obtained from endothelin determination in a multivariate model.

CONCLUSIONS

Plasma endothelin concentrations are strongly related to outcome after myocardial infarction and provide prognostic information independent of clinical and biochemical variables previously associated with a poor prognosis.

Prognostic significance of N-terminal pro-atrial natriuretic factor (1-98) in acute myocardial infarction: comparison with atrial natriuretic factor (99-126) and clinical evaluation

OBJECTIVE

To evaluate the prognostic significance of plasma N-terminal pro-atrial natriuretic factor (1-98) concentrations measured in the subacute phase after acute myocardial infarction, and to compare the predictive value of measurement of N-terminal pro-atrial natriuretic factor (1-98) with the measurement of atrial natriuretic factor (99-126) and with clinical assessment of the degree of heart failure.

DESIGN

Prospective observational.

SETTING

Norwegian central hospital.

PATIENTS

139 patients (mean (SD) age 66.9 (11.1) years, 71.2% males) with acute myocardial infarction. Patients in cardiogenic shock or with severe heart failure (New York Heart Association class IV) were excluded.

MAIN OUTCOME MEASURE

Cardiovascular death within 12 months.

RESULTS

During the follow up period 15 patients died. In a univariate Cox proportional hazards model N-terminal pro-atrial natriuretic factor (1-98) was significantly related to mortality (p = 0.0003). In a multivariate model the prognostic value of N-terminal pro-atrial natriuretic factor (1-98) was better than that of atrial natriuretic factor (99-126) and clinical assessment of heart failure (N-terminal pro-atrial natriuretic factor (1-98), p = 0.0003; atrial natriuretic factor (99-126), p = 0.4513; heart failure, p = 0.0719). The odds ratio estimate of patients in whom plasma concentrations of N-terminal pro-atrial natriuretic factor (1-98) were greater than 2000 pmol/l was 25 (95% confidence interval 2.8-225.0) compared with patients with plasma concentrations less than 1000 pmol/l.

CONCLUSIONS

These results suggest that determination of plasma N-terminal pro-atrial natriuretic factor (1-98) in the subacute phase of myocardial infarction may provide clinically relevant prognostic information that is superior to that obtained from atrial natriuretic factor (99-126) measurements and clinical evaluation.

The effect of early converting enzyme inhibition on neurohumoral activation in acute myocardial infarction

The effect of early converting enzyme inhibition with enalapril on the extent of neurohumoral activation in acute myocardial infarction was evaluated in a randomized, placebo-controlled double blind fashion. Plasma levels of atrial natriuretic factor and noradrenaline on day 1, i.e. prior to randomization (n = 99), and on days 3 (n = 145) and 30 (n = 69) following myocardial infarction were determined. Enalapril did not significantly affect neurohumoral activation on day 3 (enalapril vs. placebo (mean (S.E.M.); atrial natriuretic factor: 35.3 (3.0) vs. 37.2 (2.9) pmol/l; noradrenaline: 2.82 (0.20) vs. 3.70 (1.02) nmol/l) or at 1 month (atrial natriuretic factor: 33.1 (3.0) vs. 32.4 (3.9) pmol/l; noradrenaline: 2.77 (0.25) vs. 2.82 (0.28) nmol/l). However, in myocardial infarction patients developing heart failure, a significant attenuation of the day 3 atrial natriuretic factor, but not of the noradrenaline response, was seen (atrial natriuretic factor: 47.0 (7.7) vs. 59.0 (6.4) pmol/l, P < 0.05; noradrenaline: 3.37 (0.42) vs. 6.59 (3.26) nmol/l, P = ns). In conclusion, enalapril did not significantly reduce neurohumoral activation in acute myocardial infarction, possibly because the activation in most patients is modest and confined to the early convalescent phase. However, in patients with myocardial infarction and heart failure enalapril therapy was associated with a reduction in early plasma atrial natriuretic factor levels, compatible with decreased cardiac filling pressures.

Prognostic value of plasma atrial natriuretic factor, norepinephrine and epinephrine in acute myocardial infarction

Neurohumoral activation in acute myocardial infarction (AMI) may reflect the degree of hemodynamic compromise, contribute to the progression of heart failure and augment to the risk of serious ventricular arrhythmias. Consequently, assessment of neurohumoral variables may provide an index of prognostic value in AMI. Plasma levels of atrial natriuretic factor (ANF), norepinephrine and epinephrine were determined in 145 patients on day 3 after AMI. During the 360-day follow-up period 17 patients died. In univariate analysis, all 3 neurohormones were significantly related to 1-year mortality rates (ANF, p < 0.001; norepinephrine, p = 0.009; epinephrine, p = 0.048). After correction for age, sex, anamnestic, biochemical and clinical variables including signs of clinical heart failure in a multivariate model, ANF remained independently related to mortality. The association between plasma norepinephrine and survival failed to reach statistical significance after introduction of clinical heart failure in the model. Comparison of patients subdivided according to median hormone levels (ANF, 30.3 pmol/liter; norepinephrine, 2.29 nmol/liter) demonstrated a significantly increased mortality rate in patients with elevated ANF (p < 0.001), but not elevated norepinephrine levels. These results suggest that early plasma ANF levels are related to survival in patients with AMI, independently of signs of clinical heart failure.