Diuretic treatment and diuretic resistance in heart failure

Hyponatremia and congestive heart failure: a marker of increased mortality and a target for therapy

Heart failure is one of the most common chronic medical conditions in the developed world. It is characterized by neurohormonal activation of multiple systems that can lead to clinical deterioration and significant morbidity and mortality. In this regard, hyponatremia is due to inappropriate and continued vasopressin activity despite hypoosmolality and volume overload. Hyponatremia is also due to diuretic use in an attempt to manage volume overload. When hyponatremia occurs, it is a marker of heart failure severity and identifies patients with increased mortality. The recent introduction of specific vasopressin-receptor antagonists offers a targeted pharmacological approach to these pathophysiological derangements. Thus far, clinical trials with vasopressin-receptor antagonists have demonstrated an increase in free-water excretion, improvement in serum sodium, modest improvements in dyspnea but no improvement in mortality. Continued clinical trials with these agents are needed to determine their specific role in the treatment of both chronic and decompensated heart failure.

Ultrafiltration in the management of acute decompensated heart failure

PURPOSE OF REVIEW

Admissions to hospital for acute decompensated heart failure continue to increase and represent a significant burden on both patients' and healthcare resources. The majority of these admissions are for the control of volume overload; however, standard treatment with intravenous diuretics is not always effective and can lead to increased renal morbidity. One alternative to standard therapy is mechanical fluid removal with ultrafiltration, this review will highlight the current evidence and efficacy regarding ultrafiltration use in acute heart failure.

RECENT FINDINGS

Multiple recent clinical trials have demonstrated the safety and feasibility of ultrafiltration in the management of acute heart failure. Ultrafiltration may be more effective at removing fluid than standard diuretic therapy and has been associated with beneficial long-term results. However, it remains to be determined whether ultrafiltration is truly nephroprotective and when and how this therapy is best utilized.

SUMMARY

Ultrafiltration is an attractive alternative to standard diuretic therapy in the management of volume overload from acute heart failure. Further research is needed to confirm the cost-effectiveness and to determine long-term impacts on morbidity and mortality.

[Therapeutic strategies in acute decompensated heart failure and cardiogenic shock]

As the population of elderly people is increasing, the number of patients requiring hospitalization for acute exacerbations is rising. Traditionally, these episodes of hemodynamic instability were viewed as a transient event characterized by systolic dysfunction, low cardiac output, and fluid overload. Diuretics, along with vasodilator and inotropic therapy, eventually became elements of standard care. In a multicenter observational registry (ADHERE--Acute Decompensated Heart Failure National Registry) of more than 275 hospitals, patients with acute decompensated heart failure were analyzed for their characteristics and treatments options. These data have shown that this population consists of multiple types of heart failure, various forms of acute decompensation, combinations of comorbidities, and varying degrees of disease severity. The challenges in the treatment require multidisciplinary approaches since patients typically are elderly and have complex combinations of comorbidities. So far only a limited number of drugs is currently available to treat the different groups. Over the past years it was shown that even "standard drugs" might be deleterious by induction of myocardial injury, worsening of renal function or increasing mortality upon treatment. Therefore, based on pathophysiology, different types of acute decompensated heart failure require specialized treatment strategies.

Therapeutic options for the management of the cardiorenal syndrome

Patients with heart failure often present with impaired renal function, which is a predictor of poor outcome. The cardiorenal syndrome is the worsening of renal function, which is accelerated by worsening of heart failure or acute decompensated heart failure. Although it is a frequent clinical entity due to the improved survival of heart failure patients, still its pathophysiology is not well understood, and thus its therapeutic approach remains controversial and sometimes ineffective. Established therapeutic strategies, such as diuretics and inotropes, are often associated with resistance and limited clinical success. That leads to an increasing concern about novel options, such as the use of vasopressin antagonists, adenosine A1 receptor antagonists, and renal-protective dopamine. Initial clinical trials have shown quite encouraging results in some heart failure subpopulations but have failed to demonstrate a clear beneficial role of these agents. On the other hand, ultrafiltration appears to be a more promising therapeutic procedure that will improve volume regulation, while preserving renal and cardiac function. Further clinical studies are required in order to determine their net effect on renal function and potential cardiovascular outcomes. Until then, management of the cardiorenal syndrome remains quite empirical.

Loop diuretic therapy in heart failure: the need for solid evidence on a fluid issue

BACKGROUND

Heart failure (HF) is a common condition associated with substantial cost, morbidity, and mortality. Because results of clinical trials in the acute decompensated heart failure (ADHF) setting have been mostly neutral, loop diuretics remain the mainstay of treatment.

HYPOTHESIS

Loop diuretic use may be associated with unfavorable outcomes.

METHODS

A MEDLINE literature search was performed to identify articles relating to heart failure and loop diuretics. The current evidence on the risks and benefits of loop diuretics for the treatment of ADHF is reviewed.

RESULTS

Loop diuretics are associated with symptomatic improvements in congestion, urine output, and body weight, but have shown no long-term mortality benefit. Loop diuretics, especially at high doses, are associated with worsened renal function and other poor outcomes.

CONCLUSIONS

Loop diuretics still prove useful in HF treatment, but risk-benefit analysis of these agents in the treatment of ADHF requires a well-designed prospective study.

Natriuretic and neurohormonal responses to nesiritide, furosemide, and combined nesiritide and furosemide in patients with stable systolic dysfunction

BACKGROUND

In patients with heart failure, few data describe the neurohormonal response to nesiritide and furosemide either alone or in combination. This study systematically compared the effects of nesiritide, furosemide, and their combination on natriuresis/diuresis and plasma aldosterone in patients with chronic stable heart failure who were relatively diuretic resistant.

HYPOTHESIS

Natriuretic, diuretic, and neurohormonal responses to furosemide and nesiritide will differ when these agents are administered alone vs. in combination.

METHODS

Twenty-eight subjects completed a multicenter, open-label, three-arm crossover study. Each subject received the following treatments in random order on alternate days: (1) furosemide, 40 mg intravenous bolus; (2) nesiritide, 2 microg/kg intravenous bolus followed by a 0.01 microg/kg/min infusion for 6 hours; (3) both furosemide and nesiritide, with furosemide given at least 15 minutes after initiation of nesiritide.

RESULTS

Plasma aldosterone increased by 2.2 +/- 1.6 ng/dL after furosemide alone, decreased by 3.9 +/- 1.6 ng/dL after nesiritide alone (P = 0.005 vs furosemide alone and P = 0.56 vs furosemide plus nesiritide), and decreased by 2.8 +/- 1.6 ng/dL after furosemide plus nesiritide (P = 0.02 vs furosemide alone).

CONCLUSIONS

Furosemide alone produced natriuresis/diuresis and a prompt rise in plasma aldosterone values. Nesiritide alone produced no significant natriuresis/diuresis, but decreased plasma aldosterone values. When furosemide was administered on a background of nesiritide infusion, the observed natriuresis/diuresis was similar to that seen with furosemide alone, without the anticipated increase in plasma aldosterone observed with furosemide alone.

Loop diuretics can cause clinical natriuretic failure: a prescription for volume expansion

Ultrafiltration enhances volume removal and weight reduction vs diuretics. However, their differential impact on total body sodium, potassium, and magnesium has not been described. Fifteen patients with congestion despite diuretic therapy had urine electrolytes measured after a diuretic dose. Ultrafiltration was initiated and ultrafiltrate electrolytes were measured. The urine sodium after diuretics (60+/-47 mmol/L) was less than in the ultrafiltrate (134+/-8.0 mmol/L) (P=.000025). The urine potassium level after diuretics (41+/-23 mmol/L) was greater than in the ultrafiltrate (3.7+/-0.6 mmol/L) (P=.000017). The urine magnesium level after diuretics (5.2+/-3.1 mg/dL) was greater than in the ultrafiltrate (2.9+/-0.7 mg/dL) (P=.017). In acute decompensated heart failure patients with congestion despite diuretic therapy, diuretics are poor natriuretics and cause significant potassium and magnesium loss. Ultrafiltration extracts more sodium while sparing potassium and magnesium. The sustained clinical benefits of ultrafiltration compared with diuretics may be partly related to their disparate effects on total body sodium, potassium, and magnesium, in addition to their differential efficacy of volume removal.

Hyponatremia in heart failure: the role of arginine vasopressin and diuretics

PURPOSE

To provide an overview of the role of arginine vasopressin (AVP) in the development of hyponatremia in patients with heart failure (HF), the role of diuretics, and the potential for vasopressin-receptor antagonists in the treatment of HF.

METHODS

A MEDLINE literature search was performed to identify articles relating to HF, diuretics, hyponatremia, AVP, and vasopressin-receptor antagonists.

DISCUSSION

HF affects more than 5 million patients in the United States and is associated with substantial cost, morbidity, and mortality. One of the complications associated with HF, as well as with its treatment, is the development of hyponatremia. Hyponatremia in patients with HF is associated with poor outcomes and can limit the use of diuretic therapy. AVP is the primary stimulus to the development of hyponatremia in these patients and therapies that target AVP action would seem a logical choice in the therapeutic regimen for HF. Drugs that antagonize the vasopressin V(2) receptor, which is primarily responsible for water resorption in the kidney, are now available and have been studied in patients with HF. These drugs have been associated with improvements in serum sodium concentration, urine output, and body weight, but have shown no long-term mortality benefit in patients with HF. In a subset of patients with baseline hyponatremia, these agents improved quality of life scores.

CONCLUSION

Vasopressin-receptor antagonists may prove useful in the treatment of HF; however, the exact role of these agents in the treatment of HF still requires further study.

The protective effects of exercise and phosphoinositide 3-kinase (p110α) in the failing heart

Despite the development of a wide range of therapies, heart failure remains a leading cause of death in Western society. New therapies are needed to help combat this debilitating condition. Exercise is becoming an increasingly important feature of rehabilitation programmes for patients with heart failure. Before the 1980s, patients with heart failure were advised not to exercise as it was thought that exercise would increase the risk of a cardiac event (such as myocardial infarction). However, in recent years both aerobic and resistance training have been shown to be safe and beneficial for patients with heart failure, improving exercise tolerance and quality of life, and preventing muscular deconditioning. The molecular mechanisms responsible for exercise-induced cardioprotection are yet to be elucidated, however studies in transgenic mice have identified PI3K(p110α) (phosphoinositide 3-kinase p110α) as a likely mediator. PI3K(p110α) is a lipid kinase which is activated in the heart during chronic exercise training, and is important for maintaining heart structure and function in various pathological settings. In the present review the protective effects of PI3K(p110α) in the failing heart and its potential as a therapeutic strategy for the treatment of heart failure is discussed.

Short-term mortality and cost associated with cardiac device implantation in patients hospitalized with heart failure

BACKGROUND

The use of implantable cardiac devices in the management of heart failure has increased, but patient selection and inhospital outcomes in clinical practice have not been critically explored. Therefore, we evaluated the inhospital mortality and costs associated with patients with heart failure who received an implantable cardioverter defibrillator, cardiac resynchronization device, or device lead.

METHODS

We analyzed admissions with International Classification of Diseases, Ninth Revision, procedure codes for implantation/revision of cardioverter defibrillator or cardiac resynchronization device and a primary or secondary diagnosis code for heart failure in a prospective hospital database from 2004 to 2005. Odds ratios were calculated to quantify risk for mortality. Average accumulated costs over time were calculated before and after day of first device implant procedure.

RESULTS

Among 27,907 hospitalizations, inhospital mortality varied based on day of device implantation and use of intravenous inotropic therapy. Mortality was 0.3% for patients who did not require inotropic drugs versus 3.3%, 6.6%, and 15.2% for patients who required initiation of drug before, on the day of, or after device implantation, respectively. Logistic regression demonstrated that the most potent risk for inhospital mortality was the use of inotropic drugs. Similar trends were observed for any vasoactive therapy. There was a marked increase in costs associated with these admissions.

CONCLUSIONS

Implantation of cardiac devices during a hospitalization for heart failure may be associated with significant inhospital mortality if patients require intravenous vasoactive therapy. Risk stratification methodology that incorporates ongoing/anticipated need for these drugs will likely improve clinical decision making.

New therapies in acute decompensated heart failure

PURPOSE OF REVIEW

Hospitalization and mortality rates associated with heart failure are persistently high. This is due partly to aging of the population but mostly to delayed progress in the pharmacological treatment of decompensated heart failure. We will review the current recommendations and most recent advancement in the pharmacological treatment of acute decompensated heart failure while providing a systematic approach to the management of this prevalent condition.

RECENT FINDINGS

Loop diuretics, nitrates and inotropes such as dobutamine and milrinone are the current mainstay of acute heart failure management although their associated morbidity and possible mortality have raised serious concerns. Recent vasoactive agents such as Nesiritide, Tolvaptan and more recently the inotropic agent Levosimedan could offer improved hemodynamics and congestive relief to patients in acute pulmonary edema.

SUMMARY

Despite the promising results of these agents, further clinical trials are required prior to their international approval as first-line therapy. Although we can be optimistic that these vasoactive drugs might have favorable clinical outcomes and improve the intricate management of decompensated heart failure, their associated mortality benefit remains unclear and controversial.

Diuretics for the treatment of acute decompensated heart failure

Diuretics have been a mainstay for the treatment of acute decompensated heart failure (ADHF) for the past four decades, though their short-term gains have been questioned recently given their potential long-term deleterious systemic effects. The methods of diuretic administration as well as the optimal dosing regimen of these agents are both areas that have been increasingly coming under scrutiny. The lack of rigorous clinical trials examining diuretic use in ADHF, however, has led to a general adoption of non-evidence based treatment algorithms for this patient population. Though the use of intravenous vasodilators for the treatment of decompensated heart failure has grown tremendously over the last few years, the fact remains that diuretics are still indispensable for alleviating congestive symptoms. Given this reality and until further information is available about the most ideal utilization of these medications, diuretics will continue to represent a double-edged sword for physicians treating this disease process.

Fluid Restriction in the Management of Decompensated Heart Failure: No Impact on Time to Clinical Stability

BACKGROUND

To examine the clinical effect of fluid restriction in patients admitted to the hospital with class IV heart failure (HF).

METHODS AND RESULTS

This is a single-blind randomized controlled study. Time to clinical stability was compared between the fluid restricted (FR: n = 34) and free fluid (FF: n = 33) groups respectively showing no significant difference (8.3 +/- 6.3 days versus 7.0 +/- 6.0 days, P = .17). There was no significant difference between groups in time to discontinuation of intravenous diuretic therapy (FR: 2.7 +/- 4.5 days, FF: 3.2 +/- 5.6 days, P = .70). Changes from baseline to achievement of clinical stability in serum urea (P = .23), serum creatinine (P = .14), BNP (P = .42), and sodium (P = .14) did not differ between the FF and FR groups. Baseline serum sodium levels did not predict the time to clinical stability (beta = -0.11, 95% CI: -0.60, 0.23).

CONCLUSIONS

Fluid restriction is not an evidence-based therapy although it is occasionally applied in the management of HF. These results suggest that FR is not of any clinical benefit in patients with acute decompensated HF and this hypothesis should be tested in a larger randomized controlled study.

Practical applications of intravenous diuretic therapy in decompensated heart failure

Intravenous (IV) loop diuretics play an important role in the treatment of decompensated heart failure (DHF). They inhibit the Na(+)-K(+)-2Cl(-) reabsorptive pump in the thick ascending limb of the loop of Henle, and the resultant natriuresis and diuresis decreases volume load, improves hemodynamics, and reduces DHF symptoms. However, loop diuretics have a short half-life and their efficacy may be limited by postdiuretic sodium rebound during the period between doses in which the tubular diuretic concentration is subtherapeutic. Moreover, they can produce electrolyte abnormalities, neurohormonal activation, intravascular volume depletion, and renal dysfunction. Several studies have reported an association between diuretic therapy and increased morbidity and mortality. In addition, many patients, especially those with more advanced forms of heart failure (HF), are resistant to standard doses of loop diuretics. These high-risk, resistant patients may benefit from pharmacologic and/or nonpharmacologic interventions to improve hemodynamic performance, treatment of renovascular disease, discontinuation of aspirin and other sodium-retaining drugs, manipulation of the route of delivery or combination of diuretic classes, or hemofiltration. Despite >50 years of use, many questions regarding the use of intravenous diuretic agents in patients with DHF are still unanswered, and there remains a compelling need for well-designed randomized, controlled clinical trials to establish appropriate treatment regimens that maximize therapeutic benefit while minimizing morbidity and mortality.

Beyond diuretics: management of volume overload in acute heart failure syndromes

Diuretics are an established foundation of therapy for patients with chronic heart failure (HF) as well as for those hospitalized for treatment of acute HF syndromes. Despite the accepted use of diuretics in acute HF syndromes, treatment patterns with diuretics vary widely, and there are no data from randomized studies on the benefit of diuretics on morbidity or mortality in patients hospitalized with acute HF syndromes. Additional pharmacologic therapies that complement or replace diuretics in this setting, especially in patients with diuretic resistance, include positive inotropes, nitrovasodilators, and natriuretic peptides, but data are likewise lacking on important clinical outcomes. Ultrafiltration has also been used as a nonpharmacologic strategy to treat patients with acute HF syndromes who exhibit resistance to diuretics. Effective monitoring of volume status with newer modalities may allow more selective use of diuretics and diuretic-like modalities, but additional randomized trial data are clearly needed to establish ideal strategies to promote volume removal in acute HF syndromes.

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.

Diagnosis and management of heart failure in the outpatient setting

Heart failure is a clinical syndrome that results in diminished tissue perfusion and volume overload. Because of increasing population age and improved survival after myocardial infarction, the prevalence of heart failure is likely to increase dramatically. Primary care physicians are in an ideal position to care for patients throughout the spectrum of heart failure, from identifying patients at increased risk to managing the final stages of the disease. New understandings of heart failure pathophysiology have led to more effective treatments aimed at blocking neurohormonal pathways. There is still much to be learned about the pathophysiology and treatment of diastolic heart failure, and rapidly expanding knowledge of heart failure is likely to lead to better treatment in the coming years.

Optimizing outcomes in the patient with acute decompensated heart failure

Heart failure (HF) and episodes of acute decompensated HF (ADHF) continue to pose a substantial clinical challenge in the United States and represent a significant source of morbidity, mortality, and health care resource use. Recent therapeutic advances have shifted ADHF treatment paradigms from diuretic management with or without inotrope use to therapy where intravenous vasodilators are the central component, above a background of diuretics. This shift in treatment has resulted in more rapid symptomatic improvements as well as in decreases in overall morbidity and mortality. Elevated left ventricular filling pressure has become an important clinical target for resolution during ADHF, as this parameter most closely correlates with degree of symptoms, extent of ischemic complications, and the deleterious neurohormonal activation in response to ADHF. Therapies that lead to rapid improvements in left ventricular filling pressure, including the use of nesiritide, a recombinant analog of B-type natriuretic peptide, have been shown to provide rapid symptomatic relief, but effects on long-term morbidity and mortality are as yet unclear. In addition to new treatments, new technologies--including assays based on cardiac biomarkers and techniques such as impedance cardiography for noninvasive monitoring of hemodynamic parameters--are contributing to improvements in care that will ultimately reduce the sizeable clinical and economic burden that HF represents.

Overview of vasopressin receptor antagonists in heart failure resulting in hospitalization

Patients with worsening heart failure (HF) requiring hospitalization commonly have a history of progressive fluid retention, decreased renal function, and hyponatremia. For these patients, diuretics have traditionally been the mainstay of treatment, but they are associated with electrolyte abnormalities and impaired renal function. Previous studies have shown that levels of the endogenous arginine vasopressin (AVP) hormone are elevated in patients with HF and may be the contributing factor to fluid retention and hyponatremia, and probably progression of HF. Vasopressin antagonists represent a unique class of therapeutic agents because of their potential role in both the short- and long-term treatment of patients hospitalized with worsening HF. As "aquaretics," AVP antagonists offer the possibility of added efficacy in relieving congestion and improving symptoms with minimal adverse effects in combination with standard medical therapy. Some AVP receptor antagonists have shown promising results in animal studies and small-scale clinical trials. The purpose of this review was to update the current status of studies with the available AVP antagonists.

Hypotension is associated with diuretic resistance in severe chronic heart failure, independent of renal function

BACKGROUND

Diuretic resistance and systemic hypotension are common in chronic heart failure (CHF), however, the two have not been associated.

AIMS

Since blood pressure (BP) might be an important determinant of sodium excretion, we searched for an association between BP and diuretic dosage in severe CHF.

METHODS

Our heart failure database was retrospectively reviewed for patients with severe left ventricular systolic dysfunction. The 54-patient cohort was divided on the basis of frusemide dosage (high-dose > or = 250 mg daily, n=26).

RESULTS

Patients taking high-dose frusemide had higher serum creatinine, and lower systolic and diastolic BP. On logistic regression analysis, increased serum creatinine and reduced diastolic BP were independent predictors of the use of high-dose frusemide. Grouping these variables into tertiles, the odds ratio for the use of high-dose frusemide was 4.0 as diastolic BP decreased (p<0.01), and 6.8 as serum creatinine increased (p<0.001).

CONCLUSIONS

We have found an association between hypotension and the use of high-dose frusemide in severe CHF, which is independent of renal function, and which may be an important physiologic mechanism of diuretic resistance in severe CHF.

Adenosine A1 Receptor Antagonist Blunts Urinary Potassium Excretion, but Not Renal Hemodynamic Effects, Induced by Carbonic Anhydrase Inhibitor in Rats

Acetazolamide (AZ) is a carbonic anhydrase inhibitor with diuretic actions at the proximal tubule. Clinical use of AZ is limited, in part, because of the urinary potassium loss and decrease of renal hemodynamic function that accompanies the drug. There is recent interest in A1 adenosine receptor (A1AR) antagonists, a novel class of diuretic agents that do not cause loss of potassium or tubuloglomerular feedback- (TGF) mediated reductions of renal hemodynamics. We tested whether the A1AR antagonist 1,3-dipropyl-8-cyclopentylxanthine (DPCPX) could attenuate the adverse effects normally associated with use of AZ. Renal blood flow (RBF) and urine output were measured during two consecutive 40-min periods in anesthetized rats. In the first period, vehicle or DPCPX was infused. DPCPX alone increased urine output and sodium excretion but did not significantly alter potassium output or RBF. In the second period, the initial infusion of vehicle or DPCPX was continued, and either AZ or its vehicle was administered. AZ alone increased urinary excretion of both sodium and potassium and decreased RBF. DPCPX significantly attenuated the AZ-induced increase of potassium excretion by 50% but did not blunt the renal hemodynamic response to AZ. In a separate study, angiotensin II type 1 (AT1) receptor blockade also failed to blunt the renal hemodynamic response to AZ. In summary, A1AR antagonists may be useful diuretic agents alone or in combination with other conventional diuretic agents. The decrease of RBF that occurred in response to carbonic anhydrase inhibition was not attenuated by either A1AR blockade or AT1 receptor blockade and does not seem to be mediated by a TGF-dependent mechanism.

The benefits of early vasoactive therapy in the treatment of acute decompensated heart failure

PURPOSE

To review current issues in the management of acute decompensated heart failure (ADHF), focusing on the early initiation of intravenous (i.v.) vasoactive therapy and including the effects of vasoactive drugs on patient outcomes and the benefits and limitations of each medication class.

DATA SOURCES

Review of the worldwide scientific literature on ADHF.

CONCLUSIONS

The management of ADHF may be improved by early initiation of i.v. vasoactive therapy, reduced use of inotropic agents, and judicious use of diuretics. Data to date suggest that early treatment with the natriuretic peptide nesiritide reduces duration of hospitalization, in-hospital mortality, and requirements for i.v. inotropes and diuretics.

IMPLICATIONS FOR PRACTICE

Advance practice nurses play an integral role in the management of patients with ADHF from initial triage in the emergency department through final discharge from the hospital. Because they are typically responsible for administering medications and monitoring patient status, nurses need to be familiar with the benefits and limitations of each class of vasoactive agent. They need to recognize that prompt initiation of i.v. vasodilator therapy is important for improving patient outcomes. Further, advance practice nurses should participate in team management that promotes the use of evidence-based ADHF care by developing, using, and assertively communicating the need for processes of care that facilitate best practices.

Out-patient management of chronic heart failure

Chronic heart failure is a clinical syndrome associated with an ominous long-term prognosis and major economic consequences for Western societies. In recent years, considerable progress has been made in the pharmacological management of heart failure, and several treatments have been confirmed to confer survival and symptomatic benefits. However, pharmaceuticals remain underutilised, and the combination of several different drugs present challenges for their optimal prescription, requiring a thorough knowledge of potential side effects and complex interactions. This article reviews in detail the evidence pertaining to the out-patient pharmacological management of chronic heart failure, and offers recommendations on the use of various drugs in complex clinical conditions, or in areas of ongoing controversy.

Response of intestinal cells and macrophages to an orally administered cellulose-PEG based polymer as a potential treatment for intractable edemas

The elimination of water from the body represents a fundamental therapeutic goal in those diseases in which oedemas occur. Aim of this work is the design of a material able to absorb large amount of water to be used, by oral administration, in those cases in which resistance to diuretics appears. Sorption and mechanical properties of the cellulose based superabsorbent hydrogel acting as a water elimination system have been modulated through the insertion of molecular spacers between the crosslinks. Starting polymers are the sodium salt of carboxymethylcellulose (CMCNa), a polyelectrolyte cellulose derivative, and the hydroxyethylcellulose (HEC), a non-polyelectrolyte derivative. Polyethyleneglycol (PEG) with various molecular weights, has been linked by its free ends at two divinylsulfone (DVS) crosslinker molecules, in order to increase the average distance between two crosslinking sites and thus acting as spacer. Both the effect of concentration and molecular weight of the spacer resulted to significantly affect the hydrogel final sorption properties and thus the efficiency of the body water elimination system. Biocompatibility studies have been performed to test the hydrogel compatibility with respect to intestinal and macrophages cell lines. To investigate the effects of intestinal cells conditioned media after the contact with the gel on macrophages nitric oxide release tests have been carried out.

Natriuretic Peptides in the Perioperative Management of Cardiac Surgery Patients

Both heart failure (HF) and cardiac surgery with cardiopulmonary bypass result in a release of neurohormones, with a variety of physiologic effects. Administration of exogenous B-type natriuretic peptide (BNP) has beneficial hemodynamic effects and reduces the level of several neurohormones in HF patients. BNP is currently being investigated in the perioperative management of cardiac surgery patients and may be especially beneficial for patients with ventricular dysfunction, pulmonary hypertension, or renal dysfunction. Using a neurohormonal approach to supportive therapy may enhance future strategies for patients undergoing cardiac surgery, especially those at greatest risk for complications.

Hyponatremia in congestive heart failure

Hyponatremia has been identified as a risk factor for increased morbidity and mortality in patients with congestive heart failure (CHF) and other edematous disorders and can lead to severe neurologic derangements. Low cardiac output and blood pressure associated with CHF triggers a compensatory response by the body that activates several neurohormonal systems designed to preserve arterial blood volume and pressure. Hyponatremia in patients with CHF is primarily caused by increased activity of arginine vasopressin (AVP). AVP increases free-water reabsorption in the renal collecting ducts, increasing blood volume and diluting plasma sodium concentrations. Hyponatremia may also be triggered by diuretic therapy used in the management of symptoms of CHF. Hyponatremic disorders occur when the normal ratio of solutes to body water content is altered by parallel changes in serum sodium and osmolality. Hyponatremia is generally defined as a serum sodium ion concentration <135 to 136 mmol/L and can be broadly categorized into 2 types, dilutional or depletional. Dilutional hyponatremia is the most common form of hyponatremia and is caused by excess water retention. Depletional hyponatremia is usually hypovolemic, with an absolute deficiency of water but a relative excess of body water compared with sodium concentration.

Practical application of human B-type natriuretic peptide as a therapeutic intervention in the perioperative setting

The use of human B-type natriuretic peptide (BNP, nesiritide) as a therapeutic intervention is now well established for patients with acute decompensated heart failure. Nesiritide mimics the actions of endogenous BNP by binding to and stimulating receptors in the heart, kidney, and vasculature. Postsurgical patients are typically managed with various combinations of vasodilators, diuretics, and inotropes. Many of these therapeutic interventions lack significant proof of efficacy and are potentially deleterious to these patients, despite the acute hemodynamic improvement that results from their use. Use of nesiritide may supplant some of these therapies as an equally efficacious and possibly safer alternative in patients with decompensated heart failure. Nesiritide is a unique, balanced vasodilator that markedly decreases the signs and symptoms of heart failure in perioperative patients, and also may decrease the need for inotropic agents. This review summarizes nesiritide's mechanism of action and addresses special concerns and practical considerations for cardiothoracic surgeons and anesthesiologists. Overall, nesiritide appears to be an effective and safe therapeutic option in perioperative patients with decompensated heart failure.

Vasopressin antagonists in heart failure

The recrudescence of interest in manipulation of the arginine vasopressin system and especially of V2 vasopressin receptor blockade in heart failure stems from the limited efficacy and possible detrimental effects of loop diuretics. The "braking phenomenon," hypertrophy of the collecting duct cells, and altered pharmacodynamics contribute to loop diuretic resistance in heart failure. Selective (tolvaptan) and nonselective (conivaptan) V2 vasopressin receptor antagonists now known as "vaptans" promote free-water excretion that is labeled aquaresis and correct hyponatremia in patients with severe heart failure. A large mortality study with tolvaptan in heart failure is presently ongoing.

Prescription patterns of diuretics in chronic heart failure: a contemporary background as a clue to their role in treatment

BACKGROUND

Diuretics are the cornerstone of treatment for the congestive symptoms of heart failure (HF). Despite their widespread use, diuretic prescription data in clinical practice are scarce. In this study we evaluated the prescription pattern of diuretics in a large population of HF outpatients, enrolled by a national network of hospital-based cardiologists.

METHODS AND RESULTS

Among 11070 HF outpatients (mean age 64 +/- 12 years, 72.9% men, 29.8% New York Heart Association [NYHA] class III-IV, mean left ventricular ejection fraction [LVEF] 35+/-12%), 9247 took a diuretic, the most frequently prescribed therapeutic agent (83.5%). Loop diuretics were prescribed alone (65.5%) or combined with other diuretics in 91.6% of patients. By multivariate analysis, the strongest independent predictors of diuretic use were a previous hospital admission for HF (odds ratio [OR] 2.55, 95% confidence interval [CI] 2.28-2.86), NYHA class III-IV (OR 2.52, 95% CI 2.14-2.96), LVEF < 30% (OR 1.87, 95% CI 1.57-2.24). Aldosterone antagonists were prescribed to 2142 patients (23.1%); independent predictors of their use overlapped with those of diuretics and moreover included treatment with loop diuretics (OR 3.52, 95% CI 2.66-4.66) and digoxin (OR 1.45, 95% CI 1.29-1.64).

CONCLUSIONS

In this wide series of stable HF outpatients, cardiologists prescribed diuretics in accordance with published guidelines. Evolving prescription patterns of aldosterone-receptor blockers need to be further evaluated.

Nonpharmacologic care of heart failure: counseling, dietary restriction, rehabilitation, treatment of sleep apnea, and ultrafiltration

The prognosis of patients with chronic congestive heart failure (CHF) depends not only on pharmacologic therapy but also on nonpharmacologic aspects. A complete and ongoing education program for treating CHF includes an understanding of the causes of CHF, symptoms, diet, salt and fluid restriction, drug regimen, compliance, physical and work activities, lifestyle changes, and measures of self-control. Moreover, the nonpharmacologic treatment (dietary modifications, lifestyle, physical exercise, and health care education) must be inserted in a multidisciplinary program organized by the physician in conjunction with the health system, the nurses, and, especially, the patients themselves, who must understand their disease and the many therapeutic options. Cardiologists should treat patients in a clear and comprehensible way, and other specialists (dietitians, physiotherapists, psychologists, nurses, and social workers), together with the patient's family, should strive for the best living conditions for the patient. In this way, the treatment of CHF can improve the quantity and quality of life and save a significant amount in health care costs.

Biomedical application of a superabsorbent hydrogel for body water elimination in the treatment of edemas

A novel system of body water elimination to be used for the treatment of edemas, based on superabsorbent cellulose derivatives able to absorb large amounts of water and water solutions, has been investigated. Hydrogels have been synthesized starting from water solutions of carboxymethylcellulose sodium salt and hydroxyethylcellulose, chemically crosslinked with divinylsulphone. Polyelectrolyte hydrogels displayed high sensitivity in sorption capacity to variations of the ionic strength and pH of the external solution, which is a key parameter for the application under investigation. Further, swelling properties have been modulated acting on the degree of crosslinking of the macromolecular network, and a direct method for the measurement of this parameter based on NMR solid-state analysis has been provided. The hydrogel biocompatibility has been studied in terms of its capacity either to induce nitric oxide and lactate dehydrogenase release by macrophages or influence their viability. The eventual release of toxic substances from the hydrogel was also investigated using Swiss 3T3 fibroblasts. The results obtained from the biocompatibility studies carried out in this work are consistent with the hypothesis that this gel may represent an alternative to diuretic therapies in those pathologic conditions in which edemas occur.

Balancing diuretic therapy in heart failure: loop diuretics, thiazides, and aldosterone antagonists

In heart failure, sodium is retained by the kidneys despite increases in extracellular volume. There is activation of renin secretion, which culminates in the production of angiotensin II, causing vasoconstriction and aldosterone secretion. These synergistically produce an increase in tubular reabsorption of sodium and water. Diuretics are the mainstay of symptomatic treatment to remove excess extracellular fluid in heart failure. Diuretics that affect the ascending loop of Henle are most commonly used. Thiazide diuretics promote a much greater natriuretic effect when combined with a loop diuretic in patients with refractory edema. Recently, spironolactone, an aldosterone receptor blocking agent, has been recommended to attenuate some of the neurohormonal effects of heart failure. Regardless of the diuretic, patients need to be counseled on the importance of avoiding sodium in their diet

Diuretic resistance predicts mortality in patients with advanced heart failure

BACKGROUND

In patients with chronic heart failure (CHF), diuretic requirements increase as the disease progresses. Because diuretic resistance can be overcome with escalating doses, the evaluation of CHF severity and prognosis may be incomplete without considering the intensity of therapy.

METHODS

The prognostic importance of diuretic resistance (as evidenced by a high-dose requirement) was retrospectively evaluated in 1153 patients with advanced CHF who were enrolled in the Prospective Randomized Amlodipine Survival Evaluation (PRAISE). The relation of loop diuretic and angiotensin-converting enzyme inhibitor doses (defined by their median values) and other baseline characteristics to total and cause-specific mortality was determined by proportion hazards regression.

RESULTS

High diuretic doses were independently associated with mortality, sudden death, and pump failure death (adjusted hazard ratios [HRs] 1.37 [P =.004], 1.39 [P =.042], and 1.51 [P =.034], respectively). Use of metolazone was an independent predictor of total mortality (adjusted HR = 1.37, P =.016) but not of cause-specific mortality. Low angiotensin-converting enzyme inhibitor dose was an independent predictor of pump failure death (adjusted HR = 2.21, P =.0005). Unadjusted mortality risks of congestion and its treatment were additive and comparable to those of established risk factors.

CONCLUSIONS

The independent association of high diuretic doses with mortality suggests that diuretic resistance should be considered an indicator of prognosis in patients with chronic CHF. These retrospective observations do not establish harm or rule out a long-term benefit of diuretics in CHF, because selection bias may entirely explain the relation of prescribed therapy to death.

Pharmacotherapy in congestive heart failure: diuretic resistance and strategies to overcome resistance in patients with congestive heart failure

Congestive heart failure is a complex clinical hemodynamic disorder characterized by chronic and progressive pump failure and fluid accumulation. Although the overall impact of diuretic therapy on congestive heart failure mortality remains unknown, diuretics remain a vital component of symptomatic congestive heart failure management. Over time, sodium and water excretion are equalized before adequate fluid elimination occurs. This phenomenon is thought to occur in one out of three patients with congestive heart failure on diuretic therapy and is termed diuretic resistance. In congestive heart failure, both pharmacokinetic and pharmacodynamic alterations are thought to be responsible for diuretic resistance. Due to disease chronicity, symptomatic management is vital to improved quality of life and enhancing diuretic response is therefore pivotal.

Polypharmacy of heart failure. Creating a rational pharmacotherapeutic protocol

In the management of chronic heart failure, polypharmacy is common, necessary, and often overlooked. The increasing costs of care, noncompliance, and frequent adverse drug interactions have led to diminishing benefits by simply adding additional drugs to the already complex regimen. This review outlines a rational pharmacotherapeutic protocol based on establishing overall therapeutic goals and confirming treatment targets, tailoring therapy to individual patients by balancing beneficial and adverse drug effects, and paying particular attention to patient education and other nonpharmacologic support.