Inverse relation between aldosterone and venous capacitance in chronically treated congestive heart failure

The role of aldosterone in heart failure and the clinical benefits of aldosterone blockade

Aldosterone has a variety of detrimental effects on the heart and vasculature and is increasingly recognized as an important target in chronic heart failure, as illustrated by the Randomized Aldactone Evaluation Study. In this article, the evidence supporting the cardiovascular effects of aldosterone in humans and the proven benefits of aldosterone-receptor antagonists in heart failure shall be discussed.

Treatment of systolic heart failure in the elderly: an evidence-based review

OBJECTIVE

To review relevant literature supporting the use of β-blockers, angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), diuretics, digoxin, aldosterone antagonists, and vasodilators in the management of heart failure in an elderly patient population aged ≥65 years.

DATA SOURCES

PubMed, EMBASE, and MEDLINE searches (January 1960-April 2010) were utilized to identify primary literature using the key terms heart failure, treatment, and elderly. Additionally, reference citations from publications identified were utilized, as well as the American College of Cardiology/American Heart Association (ACC/AHA) Guidelines for the Diagnosis and Management of Chronic Heart Failure in the Adult.

STUDY SELECTION AND DATA EXTRACTION

Primary and tertiary literature, including subgroup analyses, published in English and relating to the use of pharmacotherapy in the treatment of systolic heart failure in the elderly was reviewed.

DATA SYNTHESIS

The aging of the US population is creating a higher prevalence of systolic heart failure in the elderly. Most clinical trials have established the mortality and morbidity benefit of pharmacotherapy in heart failure in nonelderly patients; however, the current ACC/AHA guidelines do not clearly delineate this benefit in persons ≥65 years of age.

CONCLUSIONS

Clinical trial data, based on limited numbers of individuals aged ≥65 years, suggest that use of β-blockers, ACE inhibitors, ARBs, aldosterone antagonists, and vasodilators (hydralazine/nitrates) have similar mortality benefit to that observed in younger patients. As supported in the ACC/AHA guidelines, these agents should be prescribed with clinical judgment to all elderly patients, with close monitoring for adverse events. Future clinical trials with greater inclusion of patients ≥65 years will help to elucidate the magnitude of benefits of optimal pharmacotherapy on mortality and morbidity rates in this population.

Renal impairment and heart failure with preserved ejection fraction early post-myocardial infarction

AIM

To study if impaired renal function is associated with increased risk of peri-infarct heart failure (HF) in patients with preserved ejection fraction (EF).

METHODS

Patients with occluded infarct-related arteries (IRAs) between 1 to 28 d after myocardial infarction (MI) were grouped into chronic kidney disease (CKD) stages based on estimated glomerular filtration rate (eGFR). Rates of early post-MI HF were compared among eGFR groups. Logistic regression was used to explore independent predictors of HF.

RESULTS

Reduced eGFR was present in 71.1% of 2160 patients, with significant renal impairment (eGFR < 60 mL/min every 1.73 m(2)) in 14.8%. The prevalence of HF was higher with worsening renal function: 15.5%, 17.8% and 29.4% in patients with CKD stages 1, 2 and 3 or 4, respectively (P < 0.0001), despite a small absolute difference in mean EF across eGFR groups: 48.2 ± 10.0, 47.9 ± 11.3 and 46.2 ± 12.1, respectively (P = 0.02). The prevalence of HF was again higher with worsening renal function among patients with preserved EF: 10.1%, 13.6% and 23.6% (P < 0.0001), but this relationship was not significant among patients with depressed EF: 27.1%, 26.2% and 37.9% (P = 0.071). Moreover, eGFR was an independent correlate of HF in patients with preserved EF (P = 0.003) but not in patients with depressed EF (P = 0.181).

CONCLUSION

A significant proportion of post-MI patients with occluded IRAs have impaired renal function. Impaired renal function was associated with an increased rate of early post-MI HF, the association being strongest in patients with preserved EF. These findings have implications for management of peri-infarct HF.

The spironolactone renaissance

Until recently, spironolactone was considered only as an antagonist at the aldosterone receptors of the epithelial cells of the kidney and was used clinically in the treatment of hyperaldosteronism and, occasionally, as a K(+)-sparing diuretic. The spironolactone renaissance started with the experimental finding that spironolactone reversed aldosterone-induced cardiac fibrosis by a cardiac action. Experimentally, spironolactone also has direct effects on blood vessels. Spironolactone reduces vascular fibrosis and injury, inhibits angiogenesis, reduces vascular tone and reduces portal hypertension. The rationale for the Randomized Aldactone Evaluation Study (RALES) of spironolactone in heart failure was that 'aldosterone escape' occurred through non-angiotensin II mechanisms. The RALES clinical trial was stopped early when it was shown that there was a 30% reduction in risk of death among the spironolactone patients. In RALES, spironolactone also reduced hospitalisation for worsening heart failure and improved the symptoms of heart failure. Other recent clinical trials have shown that spironolactone reduces cardiac and vascular collagen turnover, improves heart variability, reduces ventricular arrhythmias, improves endothelial dysfunction and dilates blood vessels in human heart failure and these effects probably all contribute to the increased survival in heart failure. Spironolactone may also be useful in the treatment of left ventricular hypertrophy, portal hypertension and cirrhosis. There have also been some recent small clinical trials of spironolactone as an anti-androgen showing potential in acne, hirsutism and precocious puberty.

Aldosterone and vascular damage

Although the aldosterone escape mechanism is well known, aldosterone has often been neglected in the pathophysiologic consequences of the activated renin-angiotensin-aldosterone system in arterial hypertension and chronic heart failure. There is now evidence for vascular synthesis of aldosterone aside from its secretion by the adrenal cortex. Moreover, aldosterone is involved in vascular smooth muscle cell hypertrophy and hyperplasia, as well as in vascular matrix impairment and endothelial dysfunction. The mechanisms of action of aldosterone may be either delayed (genomic) or rapid (nongenomic). Deleterious effects of aldosterone leading to vascular target-organ damage include (besides salt and water retention) decreased arterial and venous compliance, increased peripheral vascular resistance, and impaired autonomic vascular control due to baroreflex dysfunction.