Effects of ramipril on the neurohormonal response to exercise in patients with mild or moderate congestive heart failure

Cachexia: pathophysiology and clinical relevance

Cachexia causes weight loss and increased mortality. It affects more than 5 million persons in the United States. Other causes of weight loss include anorexia, sarcopenia, and dehydration. The pathophysiology of cachexia is reviewed in this article. The major cause appears to be cytokine excess. Other potential mediators include testosterone and insulin-like growth factor I deficiency, excess myostatin, and excess glucocorticoids. Numerous diseases can result in cachexia, each by a slightly different mechanism. Both nutritional support and orexigenic agents play a role in the management of cachexia.

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.

The syndrome of cardiac cachexia

Cachexia, i.e. body wasting, has long been recognised as a serious complication of chronic illness. The occurrence of wasting in chronic heart failure (CHF) has been known for many centuries, but it has not been investigated extensively until recently. Cardiac cachexia is a common complication of CHF which is associated with poor prognosis, independently of functional disease severity, age, measures of exercise capacity, and left ventricular ejection fraction. Patients with cardiac cachexia suffer from generalised loss of lean tissue, fat tissue, as well as bone tissue. Cachectic CHF patients are weaker and fatigue earlier. This is due to both reduced skeletal muscle mass and impaired skeletal muscle quality. Concerning the pathophysiology of cardiac cachexia, there is increasing evidence that neurohormonal and immune abnormalities may play a crucial role. Cachectic CHF patients have raised plasma levels of norepinephrine, epinephrine, and cortisol, and they show high plasma renin activity and increased plasma aldosterone levels. A number of studies have also shown that cardiac cachexia is linked to raised plasma levels of inflammatory cytokines, such as tumor necrosis factor alpha. The available evidence suggests that cardiac cachexia is a multifactorial neuroendocrine and metabolic disorder with a poor prognosis. A complex imbalance of different body systems, termed catabolic/anabolic imbalance, is likely to be responsible for the development of the wasting process. It is hoped that a better understanding of the pathophysiological mechanisms involved in cardiac cachexia will lead to novel therapeutic strategies in the (near) future.

Early neurohormonal effects of trandolapril in patients with left ventricular dysfunction and a recent acute myocardial infarction: a double-blind, randomized, placebo-controlled multicentre study

Angiotensin-converting enzyme inhibitors improve long-term survival in patients with left ventricular dysfunction after a myocardial infarction, but their mechanism of action is not entirely clear. The neurohormonal effects may be important in this respect, as well as an early hemodynamic unloading induced by these drugs. The primary objective was to assess the effect of trandolapril on plasma levels of atrial natriuretic peptide. A secondary objective was to assess the effects of trandolapril on selected neurohormones, vasoactive peptides and enzymes, which may be important in the development of left ventricular remodeling and heart failure following an acute myocardial infarction. A total of 119 patients with an acute myocardial infarction and a wall motion index < or =1.2 (16-segment echocardiographic model) were randomized to double blind treatment with trandolapril or placebo within 3-7 days after the onset of infarction. Blind treatment was discontinued 21 days after the index infarction. Venous blood samples were collected at rest, before randomization and on the day after treatment was discontinued. At the end of the study, there were no differences in plasma levels of atrial natriuretic peptide between the two treatment groups. Angiotensin-converting enzyme activity was suppressed and plasma renin activity was higher in the trandolapril group. No differences in plasma levels of N-terminal pro-atrial natriuretic peptide, brain natriuretic peptide, aldosterone, noradrenaline, adrenaline, vasopressin, big endothelin-1 and neuropeptide Y were found between the two treatment groups. There were positive correlations between several markers of neurohormonal activation at baseline and variables expressing left ventricular dysfunction and clinical heart failure. Neurohormonal activation is related to left ventricular dysfunction. The effects of 2-3 weeks of angiotensin-converting enzyme inhibition on neurohormonal activation does not predict the already established beneficial long-term effects after myocardial infarction. Thus, early modulation of circulatory neurohormone levels may not be a major mechanism for the efficacy of angiotensin-converting enzyme inhibitors in these patients. Selected plasma hormone markers may still be used to identify patients who might get the greatest benefit from treatment.

Contracted plasma and blood volume in chronic heart failure

OBJECTIVES

The purpose of this study was to determine if long-term pharmacotherapy mediated changes in intravascular plasma and blood volumes in patients with chronic heart failure (CHF).

BACKGROUND

Intravascular fluid volume expansion is an acute compensatory adaptation to ventricular dysfunction in patients with CHF. To our knowledge there are no reports on plasma and blood volume measures in clinically stable patients with CHF receiving standard pharmacotherapy. Such information may provide a better understanding of the clinical hallmarks of heart failure.

METHODS

Plasma volume (PV) and blood volume (BV) were measured in 12 patients (62.8 +/- 8.2 years old, 175.2 +/- 6.8 cm, 96.2 +/- 18.2 kg, peak oxygen consumption (VO2max) 15.2 +/- 3.3 ml/kg per min) with CHF secondary to coronary artery disease (left ventricular ejection fraction 31.2 +/- 9.7, New York Heart Association functional class 2.5 +/- 0.5) and seven healthy subjects (71.7 +/- 5.3 years old, 177.1 +/- 10.8 cm, 84.4 +/- 11.7 kg, VO2max 26.0 +/- 6.5 ml/kg per min) 3 to 4 h after eating and after supine rest using the Evan's blue dye dilution technique. Venous blood samples were collected before blue dye infusion and analyzed for hematocrit (corrected 4% for trapped plasma and venous to whole body hematocrit ratio) and hemoglobin.

RESULTS

Hematocrit was 36.6 +/- 3.5% and 37.4 +/- 1.1%, and hemoglobin was 15.4 +/- 1.9 and 16.2 +/- 1.4 g/dl for patients with CHF and control subjects, respectively. Absolute PV was 3489.3 +/- 655.0 and 3728.7 +/- 813.2 ml, and absolute BV was 5,496.8 +/- 1,025.4 and 5,942.4 +/- 1,182.2 ml in patients with CHF and control subjects, respectively. Relative PV was 34.1 +/- 12.9 versus 44.5 +/- 9.0 ml/kg (p < or = 0.05), and relative BV was 58.5 +/- 12.3 versus 70.8 +/- 12.6 ml/kg (p < or = 0.05) in patients with CHF and control subjects, respectively.

CONCLUSIONS

Our data indicate significantly lower intravascular volumes in patients with CHF than in control subjects, indicating a deconditioned state or excessive diuresis, or both. The contracted PV and BV may contribute to exercise intolerance, shortness of breath and chronic fatigue, secondary to reduced cardiac output or regional blood flow, or both.

Atrial natriuretic peptide in aged patients with iron deficiency anemia

Anemia is a common disease in elderly people. However, since hemoglobin concentration often decreases subclinically with aging because of nutritional impairment, its pathological significance is unclear. To investigate the pathological significance of low hemoglobin concentration, we studied the relation between hemoglobin levels and arrhythmia, as well as circulatory parameters. Arrhythmia was detected by Holter type ambulatory electrocardiography in 42 elderly people (aged 60 or over) living in a nursing home. Plasma concentrations of human atrial natriuretic peptide (hANP) after iron therapy were determined by immunoradiometric assay. Changes in circulatory parameters in elderly people with iron deficiency anemia were examined. Supraventricular and ventricular premature contractions significantly increased in elderly people with low hemoglobin concentrations or hematocrit. hANP increased significantly as the hemoglobin concentration decreased in 22 elderly people. Of these 22 subjects, 11 showed a low serum concentration of iron, and were administered ferrous salts. No side effects, such as nausea, occurred. After iron supplementation, the average hemoglobin level increased from 9.0 to 10.5 g/dl, and the average hANP level was reduced from 58.3+/-23.5 to 41.2+/-27.9 pg/ml, which was statistically significant by Wilcoxon's signed rank sum test. The increase in the hemoglobin level inversely correlated with the hANP level. Heart rate, blood pressure and body weight of subjects decreased significantly after iron supplementation therapy. Although hemoglobin levels were increased by iron supplementation therapy after a long period of anemia, the duration of the period with low hemoglobin levels showed no significant relation to initial hANP concentration. In conclusion, low hemoglobin levels induced secretion of hANP, and treatment of iron deficiency might exert favorable effects on the circulatory system.

Relationship between natriuretic peptides and hemodynamics in patients with heart failure at rest and after ergometric exercise

Sixteen patients with heart failure who underwent right heart catherization were studied with regard to plasma natriuretic peptide levels and hemodynamic parameters at rest and immediately after symptom-limited ergometry. Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) were measured and correlated with left ventricular ejection fraction (LVEF), mean pulmonary arterial pressure (MPAP), pulmonary arterial wedge pressure (PAWP) and cardiac index (CI). Compared to normal controls, ANP and BNP were elevated at rest. During exercise ANP and BNP increased. BNP was highly significantly correlated with LVEF (P = 0.005) at rest, whereas ANP did not (P = 0.082). BNP significantly correlated with MPAP and PAWP after exercise and showed a significant inverse correlation with CI. Our data provide evidence that BNP might be a better indicator for LVEF at rest than ANP. In addition, BNP correlates very well with MPAP and PAWP, after exercise. This close correlation is likely to reflect a correlation of BNP with left ventricular enddistolic pressure in heart failure when patients are exposed to physical exercise.

Additive beneficial effects of beta-blockers to angiotensin-converting enzyme inhibitors in the Survival and Ventricular Enlargement (SAVE) Study. SAVE Investigators

OBJECTIVES

This study assessed whether treatment with a beta-adrenergic blocking agent in addition to the use of the angiotensin-converting enzyme (ACE) inhibitor captopril decreases cardiovascular mortality and morbidity in patients with asymptomatic left ventricular dysfunction after myocardial infarction (MI) and whether the presence of neurohumoral activation at the time of hospital discharge predicts the effects of beta-blocker treatment in these patients.

BACKGROUND

Both beta-blockers and ACE inhibitors have been shown to have beneficial effects in patients with left ventricular dysfunction but no overt heart failure after MI. These patients often have persistent neurohumoral activation at the time of hospital discharge, and one would expect that patients with activation of the sympathetic nervous system derive the most benefit from treatment with beta-blockers. However, beta-blockers are underutilized in this high risk group of patients, and it is unknown whether their beneficial effects are additive to those of ACE inhibitors.

METHODS

We performed a retrospective analysis of data from the Survival and Ventricular Enlargement (SAVE) study and its neurohumoral substudy. The relations between beta-blocker use at the time of randomization and neurohumoral activation and the subsequent development of cardiovascular events were analyzed by use of Cox proportional hazards models controlling for covariates.

RESULTS

After adjustment for baseline imbalances, beta-blocker use was associated with a significant reduction in risk of cardiovascular death (30%, 95% confidence interval [CI] 12% to 44%) and development of heart failure (21%, 95% CI 3% to 36%), but the reduction in recurrent MI (11%, 95% CI 13% to 31%) was not significant. These reductions were independent of the use of captopril. Beta-blockers were not found to have a greater effect in patients with neurohumoral activation at the time of hospital discharge.

CONCLUSIONS

The beneficial effects of beta-blocker use at the time of hospital discharge in patients with asymptomatic left ventricular dysfunction after MI appear to be additive to those of captopril and other interventions known to improve prognosis. Neurohumoral activation at the time of hospital discharge fails to identify those patients who will derive the greatest benefit from treatment with beta-blockers.

Prognostic value of plasma catecholamines, plasma renin activity, and plasma atrial natriuretic peptide at rest and during exercise in congestive heart failure: comparison with clinical evaluation, ejection fraction, and exercise capacity

Survival in congestive heart failure is related to plasma catecholamines and atrial natriuretic peptide at rest, but the prognostic importance of changes during exercise is unknown. The aim of this study was to evaluate the prognostic value of catecholamines and atrial natriuretic peptide at rest and during maximal exercise in congestive heart failure, and to compare it to clinical and exercise test variables and left ventricular ejection fraction. One hundred ninety consecutive patients (136 men and 54 women; median age, 66 years; range, 42-75 years) with clinically stable congestive heart failure were included. Sixteen patients were in New York Heart Association class I, 87 in class II, 83 in class III, and 4 in class IV. Left ventricular ejection fraction was 0.30 (range, 0.06-0.74). Total survival after 1 year was 79%, after 2 years, it was 68%. Prognostic variables at univariate analysis were: plasma noradrenaline at rest (P < .0001), plasma adrenaline at rest (P = .049), and atrial natriuretic peptide at rest (P = .016). During exercise, plasma catecholamines and plasma atrial natriuretic peptide increased significantly; the change, however, was not related to survival. Six variables carried significant, independent prognostic information in a multivariate analysis: left ventricular ejection fraction (P = .03), plasma noradrenaline at rest (P = .009), New York Heart Association class III + IV (P = .005), increase in heart rate during exercise < or = 35 min-1 (P < .0001), serum creatinine > 121 mumol/L (P = .004), and serum urea > 7.6 mmol/L (P = .007). Patients with congestive heart failure have a poor survival despite intensive medical treatment. Plasma catecholamines and plasma atrial natriuretic peptide are elevated at rest and rises further during exercise; the increase, however, is not related to mortality. Plasma noradrenaline at rest contributes with further prognostic information despite knowledge of clinical and exercise variables and was the only neurohormonal variable with independent, significant prognostic information on survival.

Exercise testing in heart failure. A critical review

Exercise intolerance is one of the primary characteristics of chronic congestive heart failure (CHF). Therefore, exercise testing has been widely used in the assessment of CHF patients, both to define the severity of the disease and to assess the efficacy of pharmaceutical agents in clinical trials. A number of different exercise tests can be used, although maximal exercise testing is the most common. Maximal exercise capacity can be determined by measuring exercise duration during incremental exercise, or maximal oxygen (O2) consumption, or it can be estimated by anaerobic threshold. While baseline exercise testing in CHF patients accurately identifies and quantifies cardiac failure and determines prognosis, it is of limited value in assessing changes that occur as a result of drug therapy. A key drawback of exercise testing as a measurement of drug effect is the fact that exercise changes produced by drug intervention do not correlate well with changes in the mortality rate. Several examples of the lack of correlation between exercise testing and mortality rates have been observed in clinical trials with angiotensin converting enzyme (ACE) inhibitors and vasodilators. ACE inhibitors have a modest effect on maximal exercise capacity but they improve survival. It is thought that neuroendocrine activation more closely reflects mortality rates and also the changes in survival observed with pharmacological intervention compared with other modes of evaluation.