Heart failure in patients admitted to hospital: mortality is still high

Furosemide and spironolactone doses and hyponatremia in patients with heart failure

Background

Hyponatremia, a marker of disease severity and prognosis, has been associated with various clinical factors and drug use, especially diuretics.

Methods

This observational prospective cohort study enrolled patients hospitalized at the University Hospital Center Split because of heart failure (HF). We investigated the association of clinical variables and cardiovascular drugs, including furosemide, hydrochlorothiazide, spironolactone, and their doses, with the presence of hyponatremia at admission.

Results

Of the 565 included patients, 32.4% were hyponatremic, 62.6% were males, and the mean age was 73.1 ± 10.6 years. In the univariate analysis, hyponatremic patients were more often current smokers (p = 0.01), alcohol consumers (p = 0.01), receiving spironolactone (p = 0.004) or combination of furosemide and spironolactone (p = 0.003). Patients who received 50 and 100 mg of spironolactone, compared to those receiving 25 mg (p < 0.0001), as well as patients who received 250 to 500 mg of furosemide compared to ≤240 mg (p = 0.001), were significantly more often hyponatremic. In the multivariate analysis, when diuretic doses were accounted for, furosemide doses of 250 to 500 mg (p = 0.009), spironolactone doses of 50 to 100 mg (p = 0.0003), increasing age (p = 0.03), diabetes mellitus (p = 0.02) and alcohol consumption (p = 0.04) were independently associated with hyponatremia.

Conclusion

High doses of furosemide and spironolactone, or concomitant use of these diuretics, seem to be an important cause of hyponatremia in HF patients, particularly in combination with advanced age, diabetes and alcohol consumption. Diuretic dose reduction may help avoid hyponatremia and improve clinical status and prognosis in such patients.

Acid-base and electrolyte abnormalities in heart failure: pathophysiology and implications

Electrolyte and acid–base abnormalities are a frequent and potentially dangerous complication in subjects with congestive heart failure. This may be due either to the pathophysiological alterations present in the heart failure state leading to neurohumoral activation (stimulation of the renin–angiotensin–aldosterone system, sympathoadrenergic stimulation), or to the adverse events of therapy with diuretics, cardiac glycosides, and ACE inhibitors. Subjects with heart failure may show hyponatremia, magnesium, and potassium deficiencies; the latter two play a pivotal role in the development of cardiac arrhythmias. The early identification of these alterations and the knowledge of the pathophysiological mechanisms are very useful for the management of these patients.

Hyponatremia in patients with heart failure

The present review analyses the mechanisms relating heart failure and hyponatremia, describes the association of hyponatremia with the progress of disease and morbidity/mortality in heart failure patients and presents treatment options focusing on the role of arginine vasopressin (AVP)-receptor antagonists. Hyponatremia is the most common electrolyte disorder in the clinical setting and in hospitalized patients. Patients with hyponatremia may have neurologic symptoms since low sodium concentration produces brain edema, but the rapid correction of hyponatremia is also associated with major neurologic complications. Patients with heart failure often develop hyponatremia owing to the activation of many neurohormonal systems leading to decrease of sodium levels. A large number of clinical studies have associated hyponatremia with increased morbidity and mortality in patients hospitalized for heart failure or outpatients with chronic heart failure. Treatment options for hyponatremia in heart failure, such as water restriction or the use of hypertonic saline with loop diuretics, have limited efficacy. AVP-receptor antagonists increase sodium levels effectively and their use seems promising in patients with hyponatremia. However, the effects of AVP-receptor antagonists on hard outcomes in patients with heart failure and hyponatremia have not been thoroughly examined.

Hyponatremia and mortality: moving beyond associations

Acute hyponatremia can cause death if cerebral edema is not treated promptly. Conversely, if chronic hyponatremia is corrected too rapidly, osmotic demyelination may ensue, which also potentially is lethal. However, these severe complications of hyponatremia are relatively uncommon and often preventable. More commonly, hyponatremia predicts mortality in patients with advanced heart failure or liver cirrhosis. In these conditions, it generally is assumed that hyponatremia reflects the severity of the underlying disease rather than contributing directly to mortality. The same assumption holds for the recently reported associations between hyponatremia and mortality in patients with pulmonary embolism, pulmonary hypertension, pneumonia, and myocardial infarction. However, recent data suggest that chronic and mild hyponatremia in the general population also are associated with mortality. In addition, hyponatremia has been associated with mortality in long-term hemodialysis patients without residual function in whom the underlying disease cannot be responsible for hyponatremia. These new data raise the question of whether hyponatremia by itself can contribute to mortality or it remains a surrogate marker for other unknown risk factors. We review hyponatremia and mortality and explore the possibility that hyponatremia perturbs normal physiology in the absence of cerebral edema or osmotic demyelination.

The critical link of hypervolemia and hyponatremia in heart failure and the potential role of arginine vasopressin antagonists

BACKGROUND

Hypervolemia and hyponatremia resulting from activation of the neurohormonal system and impairment of renal function are prominent features of decompensated heart failure. Both conditions share many pathophysiologic and prognostic features and each has been associated with increased morbidity and mortality. When both conditions coexist, therapeutic options are limited.

METHODS AND RESULTS

This review presents a concise digest of the pathophysiology, clinical significance, and pharmacological therapy of hyponatremia complicating heart failure with a special emphasis on vasopressin antagonists and their aquaretic effects in the absence of neurohormonal activation along with their ability to correct hyponatremia.

CONCLUSIONS

Hypervolemia and hyponatremia share many pathophysiologic and prognostic features in heart failure. Vasopressin antagonists provide a viable option for their management and a potentially unique role when both conditions coexists.

Can hyperbaric oxygen be used as adjunctive heart failure therapy through the induction of endogenous heat shock proteins?

Heart failure (HF) is a chronic condition that is expected to increase in incidence along with increased life expectancy and an aging population. As the incidence of HF increases, the cost to national healthcare budgets is expected to run into the billions. The costs of lost productivity and increased social reliance on state support must also be considered. Recently, acute myocardial infarction (AMI) has come to be seen as the major contributing factor to HF. Although thrombolysis may restore coronary perfusion after an AMI, it may also introduce ischemic reperfusion injury (IRI). In an attempt to ameliorate sustained protein damage caused by IRI, endogenous chaperone proteins known as heat shock proteins (HSPs) are induced as a consequence of the stress of IRI. Recently, hyperbaric oxygen has been shown to induce the production of HSPs in noncardiac tissue, with a resultant protective effect. This current opinion review article suggests a possible role for hyperbaric oxygen, as a technologically modern drug, in augmenting the induction of endogenous HSPs to repair and improve the function of failing hearts that have been damaged by AMI and IRI. In addition, this simple, safe, noninvasive drug may prove useful in easing the economic burden of HF on already overextended health resources.

Treating hyponatremia in heart failure

Hyponatremia is common and associated with adverse outcomes in patients with congestive heart failure (CHF). In many patients who have CHF with hyponatremia, plasma arginine vasopressin (AVP) is elevated inappropriately. AVP causes water retention by interacting with V2 receptors in the renal collecting duct, leading to dilutional hyponatremia and increased ventricular preload. AVP also may contribute to pathophysiologic process in CHF by interacting with V(IA) receptors on vascular smooth muscle cells and myocytes. The potential utility of AVP antagonists--V2 antagonists and dual V(IA)/V2 antagonists--in correcting hyponatremia and relieving the congestion and edema associated with CHF is being actively explored. Combined antagonists may offer additional benefit by interfering with excessive V(IA) signaling. Unlike diuretics, which increase urine volume and electrolyte excretion, AVP antagonists of these types produce an aquaresis characterized by an increase in free water clearance concomitant with sparing of electrolytes. Studies in experimental CHF as well as preliminary clinical trials with selective and nonselective V2 antagonists have been encouraging, suggesting that these agents may hold promise for treatment of hyponatremia in CHF.

Economic burden of post-acute myocardial infarction heart failure in the United Kingdom

Congestive heart failure (CHF) is a major cause of morbidity and mortality. This study was carried out to quantify the burden of CHF, subsequent to acute myocardial infarction (AMI), from the perspective of the UK National Health Service (NHS). A systematic literature review of publications since 1990 was carried out on the economic burden of heart failure. The economic burden of post-AMI heart failure in the UK for the year 2000 was estimated for two scenarios: (1) Base-case estimate (post-AMI heart failure accounts for 20% of heart failure cases): Direct healthcare costs of pound 125-181 million (approx. 0.4% of total NHS spend) and nursing home costs of pound 27 million; (2) Upper estimate (post-AMI heart failure accounts for 50% of the total): Direct healthcare costs of pound 313-453 million (approx 1.0% of total NHS spend) and nursing home costs of pound 68 million. In conclusion, post-AMI heart failure imposes a significant direct economic burden on the UK.

Dilated versus nondilated cardiomyopathy in the elderly population treated with guideline-based medical therapy for systolic chronic heart failure

BACKGROUND

Although the process by which the left ventricular (LV) remodels in response to an injury generally leads to dilatation, in patients with heart failure (HF) the recognition of a small or mildly dilated left ventricle is not uncommon. We investigated the prevalence and the characteristics of elderly patients with traditional dilated and nondilated cardiomyopathy (CMP). We also assessed the response to the guideline-based medical therapy and the prognosis based on LV dilatation in this population.

METHODS AND RESULTS

We selected 243 patients >70 years of age with HF and LV ejection fraction <40% who underwent clinical and echocardiographic evaluations at baseline and after 12 months. They were subdivided into 2 groups according to baseline LV end-diastolic volume (LVEDV) (values < or =78 mL/m(2) identified nondilated CMP). Nondilated CMP was recognized in 64 patients (26%) who showed at baseline better clinical status, less severe mitral regurgitation, and higher LV ejection fraction than those with dilated CMP. At the final evaluation, favorable changes in clinical and echocardiographic parameters could be detected in both groups. The magnitude of these variations did not differ between the groups. The risk of hospitalization for worsening HF was 2.4-fold higher in patients with nondilated than dilated CMP. Mortality was 11% and 20%, respectively (P = .06). Statistical analysis revealed a direct, approximately linear relationship between LVEDV and outcomes in this population.

CONCLUSIONS

A total of 1 of 4 elderly patients with systolic HF had a nondilated left ventricle. These patients had a better clinical presentation than did counterparts with dilated left ventricles. After HF therapy is optimized, the likelihood of improvement is independent of LV size in this population, whereas the risk of death or worsening HF linearly increases with LV dilatation.