Metolazone in treatment of severe refractory congestive cardiac failure

Comparison of chlorthalidone and spironolactone as additional diuretic therapy in patients with acute heart failure and preserved ejection fraction

AIMS

Patients with acute heart failure (AHF) require intensification in the diuretic strategy. However, the optimal diuretic strategy remains unclear. In this work, we aimed to evaluate the effect of chlorthalidone compared with spironolactone on diuretic efficacy and safety profile in a cohort of patients with AHF and preserved ejection fraction (AHF-pEF).

METHODS AND RESULTS

It was a prospective observational study in a single centre in Spain, included 44 consecutive patients admitted between June 2020 and March 2021, with AHF-pEF in which an additional diuretic was prescribed. The primary endpoint was changes in urinary sodium at 24 and 72 h, and the secondary were urine output, and other security endpoints. Mixed linear regression models were used to analyse the endpoints. Estimates were reported as least squares mean with their respective 95% confidence intervals. The median age of the study population was 85 years (82.5-88.5), and 30 (68.2%) were women. After multivariate analysis, the linear mixed regression analysis confirmed a greater natriuretic response of chlorthalidone over spironolactone, especially at 24 h (P = 0.009). Multivariate analysis also showed a greater cumulative diuretic response in those treated with chlorthalidone (P = 0.001). We did not find significant differences in glomerular filtration rate, serum sodium, and serum potassium at 72 h, neither significant differences were found in 24 and 72 h in systolic blood pressure.

CONCLUSION

In patients with AHF and left ventricular ejection fraction ≥50% receiving intravenous loop diuretics, chlorthalidone administration was associated with a greater short-term natriuresis.

Quantification and treatment of congestion in heart failure: A clinical and pathophysiological overview

Renal sodium and water retention with resulting extracellular volume expansion and redistribution are hallmark features of heart failure syndromes. However, congestion assessment, monitoring, and treatment represent a real challenge in daily clinical practice. This document reviewed historical and contemporary evidence of available methods for determining volume status and discuss pharmacological aspects and pathophysiological principles that underlie diuretic use.

Quantification and Treatment of Congestion in Heart Failure: A Clinical and Pathophysiological Overview

Renal sodium and water retention with resulting extracellular volume expansion and redistribution are hallmark features of heart failure syndromes. However, congestion assessment, monitoring, and treatment represent a real challenge in daily clinical practice. This document reviewed historical and contemporary evidence of available methods for determining volume status and discuss pharmacological aspects and pathophysiological principles that underlie diuretic use.

The pathophysiology and management of diuretic resistance in patients with heart failure

OBJECTIVES

The objectives of the study are to investigate the causes of diuretic resistance in patients with advanced congestive heart failure (CHF), since diuretics are the cornerstone of treatment of these patients. Several studies have shown that diuretic resistance in patients with advanced CHF is common, ranging from 25% to 50% in hospitalized patients.

METHODS

In order to get a current perspective as to the magnitude of diuretic resistance in such patients, a focused Medline search of the English language literature was conducted between 2015 and 2020 using the search terms, CHF, diuretics, treatment, resistance, frequency, and 30 papers with pertinent information were selected.

RESULTS

The analysis of data from the selected papers demonstrated that diuretic resistance is common in hospitalized patients with advanced CHF and frequently associated with renal failure, which is secondary to CHF.

CONCLUSIONS

Diuretic resistance appears to be common in patients with advanced CHF and it is mostly due to decreased cardiac output, low blood pressure, decreased glomerular filtration rate, decreased filtration of sodium, and increased tubular reabsorption of sodium. Diuretic resistance in such patients can be overcome with the combination of loop diuretics with thiazide and thiazide-like diuretics, aldosterone antagonists, as well as other agents. The data from these studies in combination with collateral literature will be discussed in this review.

Diuretic Resistance in Heart Failure

Decompensated heart failure accounts for approximately 1 million hospitalizations in the United States annually, and this number is expected to increase significantly in the near future. Diuretics provide the initial management in most patients with fluid overload. However, the development of diuretic resistance remains a significant challenge in the treatment of heart failure. Due to the lack of a standard definition, the prevalence of this phenomenon remains difficult to determine, with some estimates suggesting that 25-30% of patients with heart failure have diuretic resistance. Certain characteristics, including low systolic blood pressures, renal impairment, and atherosclerotic disease, help predict the development of diuretic resistance. The underlying pathophysiology is likely multifactorial, with pharmacokinetic alterations, hormonal dysregulation, and the cardiorenal syndrome having significant roles. The therapeutic approach to this common problem typically involves increases in the diuretic dose and/or frequency, sequential nephron blockade, and mechanical fluid movement removal with ultrafiltration or peritoneal dialysis. Paracentesis is potentially useful in patients with intra-abdominal hypertension.

Outcomes Associated With a Strategy of Adjuvant Metolazone or High-Dose Loop Diuretics in Acute Decompensated Heart Failure: A Propensity Analysis

Background

In acute decompensated heart failure, guidelines recommend increasing loop diuretic dose or adding a thiazide diuretic when diuresis is inadequate. We set out to determine the adverse events associated with a diuretic strategy relying on metolazone or high‐dose loop diuretics.

Methods and Results

Patients admitted to 3 hospitals using a common electronic medical record with a heart failure discharge diagnosis who received intravenous loop diuretics were studied in a propensity‐adjusted analysis of all‐cause mortality. Secondary outcomes included hyponatremia (sodium <135 mEq/L), hypokalemia (potassium <3.5 mEq/L) and worsening renal function (a ≥20% decrease in estimated glomerular filtration rate). Of 13 898 admissions, 1048 (7.5%) used adjuvant metolazone. Metolazone was strongly associated with hyponatremia, hypokalemia, and worsening renal function (P<0.0001 for all) with minimal effect attenuation following covariate and propensity adjustment. Metolazone remained associated with increased mortality after multivariate and propensity adjustment (hazard ratio=1.20, 95% confidence interval 1.04–1.39, P=0.01). High‐dose loop diuretics were associated with hypokalemia and hyponatremia (P<0.002) but only worsening renal function retained significance (P<0.001) after propensity adjustment. High‐dose loop diuretics were not associated with reduced survival after multivariate and propensity adjustment (hazard ratio=0.97 per 100 mg of IV furosemide, 95% confidence interval 0.90–1.06, P=0.52).

Conclusions

During acute decompensated heart failure, metolazone was independently associated with hypokalemia, hyponatremia, worsening renal function and increased mortality after controlling for the propensity to receive metolazone and baseline characteristics. However, under the same experimental conditions, high‐dose loop diuretics were not associated with hypokalemia, hyponatremia, or reduced survival. The current findings suggest that until randomized control trial data prove otherwise, uptitration of loop diuretics may be a preferred strategy over routine early addition of thiazide type diuretics when diuresis is inadequate.

Cardiorenal Syndrome and Heart Failure-Challenges and Opportunities

Cardiorenal syndromes (CRS) describe concomitant bidirectional dysfunction of the heart and kidneys in which 1 organ initiates, perpetuates, and/or accelerates decline of the other. CRS are common in heart failure and universally portend worsened prognosis. Despite this heavy disease burden, the appropriate diagnosis and classification of CRS remains problematic. In addition to the hemodynamic drivers of decreased renal perfusion and increased renal vein pressure, induction of the renin-angiotensin-aldosterone system, stimulation of the sympathetic nervous system, disruption of balance between nitric oxide and reactive oxygen species, and inflammation are implicated in the pathogenesis of CRS. Medical therapy of heart failure including renin-angiotensin-aldosterone system inhibition and β-adrenergic blockade can blunt these deleterious processes. Renovascular disease can accelerate the progression of CRS. Volume overload and diuretic resistance are common and complicate the management of CRS. In heart failure and CRS being treated with diuretics, worsening creatinine is not associated with worsened outcome if clinical decongestion is achieved. Adjunctive therapy is often required in the management of volume overload in CRS, but evidence for these therapies is limited. Anemia and iron deficiency are importantly associated with CRS and might amplify decline of cardiac and renal function. End-stage cardiac and/or renal disease represents an especially poor prognosis with limited therapeutic options. Overall, worsening renal function is associated with significantly increased mortality. Despite progress in the area of CRS, there are still multiple pathophysiological and clinical aspects of CRS that need further research to eventually develop effective therapeutic options.

Oral Metolazone Versus Intravenous Chlorothiazide as an Adjunct to Loop Diuretics for Diuresis in Acute Decompensated Heart Failure With Reduced Ejection Fraction

Background: Thiazide diuretics are often utilized to overcome loop diuretic resistance when treating acute decompensated heart failure (ADHF). In addition to a large cost advantage, several pharmacokinetic advantages exist when administering oral metolazone (MTZ) compared with intravenous (IV) chlorothiazide (CTZ), yet many providers are reluctant to utilize an oral formulation to treat ADHF. The purpose of this study was to compare the increase in 24-hour total urine output (UOP) after adding MTZ or CTZ to IV loop diuretics (LD) in patients with heart failure with reduced ejection fraction (HFrEF). Methods and Results: From September 2013 to August 2016, 1002 patients admitted for ADHF received either MTZ or CTZ in addition to LD. Patients were excluded for heart failure with preserved ejection fraction (HFpEF) (n = 469), <24-hour LD or UOP data prior to drug initiation (n = 129), or low dose MTZ/CTZ (n = 91). A total of 168 patients were included with 64% receiving CTZ. No significant difference was observed between the increase in 24-hour total UOP after MTZ or CTZ initiation (1458 [514, 2401] mL vs 1820 [890, 2750] mL, P = .251). Conclusions: Both MTZ and CTZ similarly increased UOP when utilized as an adjunct to IV LD. These results suggest that while thiazide agents can substantially increase UOP in ADHF patients with HFrEF, MTZ and CTZ have comparable effects.

2017 Comprehensive Update of the Canadian Cardiovascular Society Guidelines for the Management of Heart Failure

Since the inception of the Canadian Cardiovascular Society heart failure (HF) guidelines in 2006, much has changed in the care for patients with HF. Over the past decade, the HF Guidelines Committee has published regular updates. However, because of the major changes that have occurred, the Guidelines Committee believes that a comprehensive reassessment of the HF management recommendations is presently needed, with a view to producing a full and complete set of updated guidelines. The primary and secondary Canadian Cardiovascular Society HF panel members as well as external experts have reviewed clinically relevant literature to provide guidance for the practicing clinician. The 2017 HF guidelines provide updated guidance on the diagnosis and management (self-care, pharmacologic, nonpharmacologic, device, and referral) that should aid in day-to-day decisions for caring for patients with HF. Among specific issues covered are risk scores, the differences in management for HF with preserved vs reduced ejection fraction, exercise and rehabilitation, implantable devices, revascularization, right ventricular dysfunction, anemia, and iron deficiency, cardiorenal syndrome, sleep apnea, cardiomyopathies, HF in pregnancy, cardio-oncology, and myocarditis. We devoted attention to strategies and treatments to prevent HF, to the organization of HF care, comorbidity management, as well as practical issues around the timing of referral and follow-up care. Recognition and treatment of advanced HF is another important aspect of this update, including how to select advanced therapies as well as end of life considerations. Finally, we acknowledge the remaining gaps in evidence that need to be filled by future research.

A perspective on diuretic resistance in chronic congestive heart failure

Chronic congestive heart failure (CHF) is a complex disorder characterized by inability of the heart to keep up the demands on it, followed by the progressive pump failure and fluid accumulation. Although the loop diuretics are widely used in heart failure (HF) patients, both pharmacodynamic and pharmacokinetic alterations are thought to be responsible for diuretic resistance in these patients. Strategies to overcome diuretic resistance include sodium intake restriction, changes in diuretic dose and route of administration and sequential nephron diuretic therapy. In this review, we discuss the definition, prevalence, mechanism of development and management strategies of diuretic resistance in HF patients.

Decongestion: Diuretics and other therapies for hospitalized heart failure

Acute heart failure (AHF) is a potentially life-threatening clinical syndrome, usually requiring hospital admission. Often the syndrome is characterized by congestion, and is associated with long hospital admissions and high risk of readmission and further healthcare expenditure. Despite a limited evidence-base, diuretics remain the first-line treatment for congestion. Loop diuretics are typically the first-line diuretic strategy with some evidence that initial treatment with continuous infusion or boluses of high-dose loop diuretic is superior to an initial lower dose strategy. In patients who have impaired responsiveness to diuretics, the addition of an oral thiazide or thiazide-like diuretic to induce sequential nephron blockade can be beneficial. The use of intravenous low-dose dopamine is no longer supported in heart failure patients with preserved systolic blood pressure and its use to assist diuresis in patients with low systolic blood pressures requires further study. Mechanical ultrafiltration has been used to treat patients with heart failure and fluid retention, but the evidence-base is not robust, and its place in clinical practice is yet to be established. Several novel pharmacological agents remain under investigation.

Addition of indapamide to frusemide increases natriuresis and creatinine clearance, but not diuresis, in fluid overloaded ICU patients

BACKGROUND

Fluid and sodium overload are a common problem in critically ill patients. Frusemide may result in diuresis in excess of natriuresis. The addition of indapamide may achieve a greater natriuresis, and also circumvent some of the problems associated with frusemide. The objective of this study was to examine the effect of adding indapamide to frusemide on diuresis, natriuresis, creatinine clearance and serum electrolytes.

METHODS

Fluid overloaded ICU patients were randomised to either intravenous frusemide (Group F) or intravenous frusemide and enteral indapamide (Group F + I). Comprehensive exclusion criteria were applied to address confounders. 24 hour urine was analysed for electrolytes and creatinine. Serum electrolytes were measured before and 24 hours after administration of diuretics.

RESULTS

Forty patients (20 in each group) were included in the study. The groups were similar in their baseline characteristics. Over the 24 h study period, patients in Group F + I, had a larger natriuresis (P = 0.01), chloride loss (P = 0.01) and kaliuresis (P = 0.047). Patients in Group F + I also had a greater 24 hour urinary creatinine clearance (P = 0.01). The 24 hour urine volume and fluid balance was similar between the groups. Patients in Group F had an increase in serum sodium (P = 0.04), while patients in Group F + I had a decrease in both serum chloride (P = 0.01) and peripheral oedema (P < 0.001) during the study duration.

CONCLUSION

In fluid overloaded ICU patients, addition of indapamide to frusemide led to a greater natriuresis and creatinine clearance. Such a strategy might be utilised in optimising sodium balance in ICU patients.

Rationale and Design of the "Safety and Efficacy of the Combination of Loop with Thiazide-type Diuretics in Patients with Decompensated Heart Failure (CLOROTIC) Trial:" A Double-Blind, Randomized, Placebo-Controlled Study to Determine the Effect of Combined Diuretic Therapy (Loop Diuretics With Thiazide-Type Diuretics) Among Patients With Decompensated Heart Failure

BACKGROUND

Fluid overload refractory to loop diuretic therapy can complicate acute or chronic heart failure (HF) management. The Safety and Efficacy of the Combination of Loop with Thiazide-type Diuretics in Patients with Decompensated Heart Failure (CLOROTIC) trial (Clinicaltrials.gov identifier NCT01647932) will test the hypothesis that blocking distal tubule sodium reabsorption with hydrochlorothiazide can antagonize the renal adaptation to chronic loop diuretic therapy and improve diuretic resistance.

METHODS

CLOROTIC is a randomized, placebo-controlled, double-blind, multicenter study. Three hundred and four patients with decompensated HF will be randomly assigned to receive hydrochlorothiazide or placebo in addition to a furosemide regimen. The main inclusion criteria are: age ≥18 years, history of chronic HF (irrespective of etiology and/or ejection fraction), admission for acute decompensation, and previous treatment with an oral loop diuretic for at least 1 month before randomization. The 2 coprimary endpoints are changes in body weight and changes in patient-reported dyspnea during hospital admission. Morbidity, mortality, and safety aspects will also be addressed.

CONCLUSIONS

CLOROTIC is the first large-scale trial to evaluate whether the addition of a thiazide diuretic (hydrochlorothiazide) to a loop diuretic (furosemide) is a safe and effective strategy for improving congestive symptoms resulting from HF. This trial will provide important information and will therefore have a major impact on treatment strategies and future trials in these patients.

Drug Therapy for Acute Heart Failure

Acute heart failure is globally one of most frequent reasons for hospitalization and still represents a challenge for the choice of the best treatment to improve patient outcome. According to current international guidelines, as soon as patients with acute heart failure arrive at the emergency department, the common therapeutic approach aims to improve their signs and symptoms, correct volume overload, and ameliorate cardiac hemodynamics by increasing vital organ perfusion. Recommended treatment for the early management of acute heart failure is characterized by the use of intravenous diuretics, oxygen, and vasodilators. Although these measures ameliorate the patient's symptoms, they do not favorably impact on short- and long-term mortality. Consequently, there is a pressing need for novel agents in acute heart failure treatment with the result that research in this field is increasing worldwide.

Predicting outcomes among patients with atrial fibrillation and heart failure receiving anticoagulation with warfarin

Among patients receiving oral anticoagulation for atrial fibrillation (AF), heart failure (HF) is associated with poor anticoagulation control. However, it is not known which patients with heart failure are at greatest risk of adverse outcomes. We evaluated 62,156 Veterans Health Administration (VA) patients receiving warfarin for AF between 10/1/06-9/30/08 using merged VA-Medicare dataset. We predicted time in therapeutic range (TTR) and rates of adverse events by categorising patients into those with 0, 1, 2, or 3+ of five putative markers of HF severity such as aspartate aminotransferase (AST)> 80 U/l, alkaline phosphatase> 150 U/l, serum sodium< 130 mEq/l, any receipt of metolazone, and any inpatient admission for HF exacerbation. These risk categories predicted TTR: patients without HF (referent) had a mean TTR of 65.0 %, while HF patients with 0, 1, 2, 3 or more markers had mean TTRs of 62.2 %, 57.2 %, 53.5 %, and 50.7 %, respectively (p< 0.001). These categories also discriminated for major haemorrhage well; compared to patients without HF, HF patients with increasing severity had hazard ratios of 1.84, 3.06, 3.52 and 5.14 respectively (p< 0.001). However, although patients with HF had an elevated hazard for bleeding compared to those without HF, these categories did not effectively discriminate risk of ischaemic stroke across HF. In conclusion, we developed a HF severity model using easily available clinical characteristics that performed well to risk-stratify patients with HF who are receiving anticoagulation for AF with regard to major haemorrhage.

[Diuretic therapy in heart failure]

Many of the primary clinical manifestations of heart failure (HF) are due to fluid retention, and treatments targeting congestion play a central role in HF management. Diuretic therapy remains the cornerstone of congestion treatment, and diuretics are prescribed to the majority of HF patients. Despite this ubiquitous use, there is limited evidence from prospective randomized studies to guide the use of diuretics. With the chronic use of diuretic and usually in advanced stages of HF, diuretics may fail to control salt and water retention. This review describes the mechanism of action of available diuretic classes, reviews their clinical use based on scientific evidence and discusses strategies to overcome diuretic resistance.

The 2012 Canadian Cardiovascular Society heart failure management guidelines update: focus on acute and chronic heart failure

The 2012 Canadian Cardiovascular Society Heart Failure (HF) Guidelines Update provides management recommendations for acute and chronic HF. In 2006, the Canadian Cardiovascular Society HF Guidelines committee first published an overview of HF management. Since then, significant additions to and changes in many of these recommendations have become apparent. With this in mind and in response to stakeholder feedback, the Guidelines Committee in 2012 has updated the overview of both acute and chronic heart failure diagnosis and management. The 2012 Update also includes recommendations, values and preferences, and practical tips to assist the medical practitioner manage their patients with HF.

Intravenous diuretic day-care treatment for patients with heart failure

Fluid overload is a common manifestation of decompensated chronic heart failure. This paper reports on a pilot study that investigated whether intravenous (i.v.) furosemide administered on a cardiology day ward for three successive days was effective in improving the symptoms of patients with fluid overload and chronic heart failure. The results showed that 94.1% of patients reported an improvement in their breathlessness, with a marked weight loss in 88.2% of patients. There were no marked changes in blood pressure or renal function. Hospital admission was avoided in 94.1% of cases. The study concluded that i.v. diuretic treatment given in a hospital day-care setting is safe and effective, and that it reduces the need for hospital admissions. As a consequence, this reduces the associated financial costs of hospitalisation.

The Synthesis and Evaluation of Dihydroquinazolin-4-ones and Quinazolin-4-ones as Thyroid Stimulating Hormone Receptor Agonists

We herein describe the rapid synthesis of a diverse set of dihydroquinazolin-4-ones and quinazolin-4-ones, their biological evaluation as thyroid stimulating hormone receptor (TSHR) agonists, and SAR analysis. Among the compounds screened, 8b was 60-fold more potent than the hit compound 1a, which was identified from a high throughput screen of over 73,000 compounds.

Metabolic and toxicological considerations for diuretic therapy in patients with acute heart failure

INTRODUCTION

Diuretics are widely recommended in patients with acute heart failure (AHF). However, loop diuretics predispose patients to electrolyte imbalance and hypovolemia, which in turn leads to neurohormonal activation and worsening renal function (WRF). Unfortunately, despite their widespread use, limited data from randomized clinical trials are available to guide clinicians with the appropriate management of this diuretic therapy.

AREAS COVERED

This review focuses on the current management of diuretic therapy and discusses data supporting the efficacy and safety of loop diuretics in patients with AHF. The authors consider the challenges in performing clinical trials of diuretics in AHF, and describe ongoing clinical trials designed to rigorously evaluate optimal diuretic use in this syndrome. The authors review the current evidence for diuretics and suggest hypothetical bases for their efficacy relying on the complex relationship among diuretics, neurohormonal activation, renal function, fluid and sodium management, and heart failure syndrome.

EXPERT OPINION

Data from several large registries that evaluated diuretic therapy in hospitalized patients with AHF suggest that its efficacy is far from being universal. Further studies are warranted to determine whether high-dose diuretics are responsible for WRF and a higher rate of coexisting renal disease are instead markers of more severe heart failure. The authors believe that monitoring congestion during diuretic therapy in AHF would refine the current approach to AHF treatment. This would allow clinicians to identify high-risk patients and possibly reduce the incidence of complications secondary to fluid management strategies.

Challenges in advanced chronic heart failure: drug therapy

Despite advances in both drug and device treatment of chronic heart failure (CHF) over the last 20 years, many patients still progress to a stage of advanced CHF, characterized by increasing symptoms and declining functional status. Future drug management of such patients presents many challenges. This review focuses on the issue of optimizing standard medical therapy in advanced CHF, the treatment of diuretic resistance and hyponatremia. As well as prescribing drugs in this phase of the disease, the system of care used to deliver therapy is crucial. On its own, multiprofessional heart failure care can improve outcomes for these patients. Finally, this review also addresses the drugs and model of care used to deliver palliative care in the end stage of advanced CHF.

A Review of Critical Differences among Loop, Thiazide, and Thiazide-Like Diuretics

Diuretics are a drug class with heterogeneous assortments. This article reviews general pharmacologic mechanisms and clinical implications of loop, thiazide, and thiazide-like diuretics.

Loop diuretics act in the loop of Henle by blocking the sodium-potassium-chloride (Na+-K+-2Cl-) symport. They are effective in relieving congestive symptoms and edematous signs of heart failure. Activation of the neurohormonal system and subsequent pathologic myocardial remodeling limit the use of loop diuretics unless fluid balance is not met to relieve patients' symptoms with life-saving pharmacologic modalities. Adverse effects on electrolyte balance may cause life-threatening consequences. The combination of K+-sparing diuretics or angiotensin-converting enzyme inhibitors with loop diuretics may not only prevent life-threatening complications caused by electrolyte imbalance, but also may delay progression of the disease with proven mortality benefit. Recent findings of worsening renal function and higher mortality rate with the use of oral and intravenous loop diuretics further demands appropriate use of these drugs.

Thiazide diuretics and thiazide-like diuretics act in the distal convoluted tubule by blocking Na+-Cl- symport. Thiazide diuretics reduce cardiovascular mortality by achieving target blood pressure in patients with hypertension. Compared with other antihypertensive drugs, thiazide diuretics have less desirable metabolic effects. However, it has not yet been shown that the negative metabolic effects of these drugs are associated with negative mortality and morbidity. Based on the need for a multidrug regimen to reach target blood pressure in most patients with hypertension, thiazide diuretics may be used in addition to a drug or drugs without metabolic complications.

Practical recommendations for prehospital and early in-hospital management of patients presenting with acute heart failure syndromes

Guideline recommendations for the prehospital and early in-hospital (first 6-12 hrs after presentation) management of acute heart failure syndromes are lacking. The American College of Cardiology/American Heart Association and European Society of Cardiology guidelines direct the management of these acute heart failure patients, but specific consensus on early management has not been published, primarily because few early management trials have been conducted. This article summarizes practical recommendations for the prehospital and early management of patients with acute heart failure syndromes; the recommendations were developed from a meeting of experts in cardiology, emergency medicine, and intensive care medicine from Europe and the United States. The recommendations are based on a unique clinical classification system considering the initial systolic blood pressure and other symptoms: 1) dyspnea and/or congestion with systolic blood pressure >140 mm Hg; 2) dyspnea and/or congestion with systolic blood pressure 100-140 mm Hg; 3) dyspnea and/or congestion with systolic blood pressure <100 mm Hg; 4) dyspnea and/or congestion with signs of acute coronary syndrome; and 5) isolated right ventricular failure. These practical recommendations are not intended to replace existing guidelines. Rather, they are meant to serve as a tool to facilitate guideline implementation where data are available and to provide suggested treatment approaches where formal guidelines and definitive evidence are lacking.

Canadian Cardiovascular Society Consensus Conference recommendations on heart failure update 2007: Prevention, management during intercurrent illness or acute decompensation, and use of biomarkers

Heart failure is common, yet it is difficult to treat. It presents in many different guises and circumstances in which therapy needs to be individualized. The Canadian Cardiovascular Society published a comprehensive set of recommendations in January 2006 on the diagnosis and management of heart failure, and the present update builds on those core recommendations. Based on feedback obtained through a national program of heart failure workshops during 2006, several topics were identified as priorities because of the challenges they pose to health care professionals. New evidence-based recommendations were developed using the structured approach for the review and assessment of evidence adopted and previously described by the Society. Specific recommendations and practical tips were written for the prevention of heart failure, the management of heart failure during intercurrent illness, the treatment of acute heart failure, and the current and future roles of biomarkers in heart failure care. Specific clinical questions that are addressed include: which patients should be identified as being at high risk of developing heart failure and which interventions should be used? What complications can occur in heart failure patients during an intercurrent illness, how should these patients be monitored and which medications may require a dose adjustment or discontinuation? What are the best therapeutic, both drug and nondrug, strategies for patients with acute heart failure? How can new biomarkers help in the treatment of heart failure, and when and how should BNP be measured in heart failure patients? The goals of the present update are to translate best evidence into practice, to apply clinical wisdom where evidence for specific strategies is weaker, and to aid physicians and other health care providers to optimally treat heart failure patients to result in a measurable impact on patient health and clinical outcomes in Canada.

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.

The confounding issue of comorbid renal insufficiency

The United States is currently beleaguered by twin epidemics, heart failure (HF) and renal insufficiency (RI). HF and RI frequently coexist in the same patient, and this conjunction, often called the "cardiorenal syndrome," has important therapeutic and prognostic implications. Approximately 60% to 80% of patients hospitalized for HF have at least stage III renal dysfunction as defined by the National Kidney Foundation (NKF), and this comorbid RI is associated with significantly increased morbidity and mortality risk. Numerous studies have demonstrated that in patients with HF, indices of renal function are the most powerful independent mortality risk predictors. Comorbid RI can result from both intrinsic renal disease and inadequate renal perfusion. Atherosclerosis, renal vascular disease, diabetes mellitus, and hypertension are significant precursors of both HF and RI. Moreover, diminished renal perfusion is frequently a consequence of the hemodynamic changes associated with HF and its treatment. Both HF and RI stimulate neurohormonal activation, increasing both preload and afterload and reducing cardiac output. Inotropic agents augment this neurohormonal activation. In addition, diuretics can produce hypovolemia and intravenous vasodilators can cause hypotension, further diminishing renal perfusion. Management of these patients requires successfully negotiating the delicate balance between adequate volume reduction and worsening renal function. Despite this, few evidence-based data are available to guide management decisions, indicating a compelling need for additional studies in this patient population.

Diuretic resistance in heart failure

The use of diuretics for the treatment of heart failure (HF) is ubiquitous in any basic HF medical regimen. Although initially these drugs clearly show benefit by relieving symptomatic episodes of decompensated HF, long-term use of these drugs can lead to a "diuretic-resistant" state and is associated with an increased risk of morbidity and mortality. A number of factors may be responsible for this, including dietary noncompliance, inadequate diuretic dosing or methods of administration, and concomitant use of certain medications. Diuretics themselves may set in motion an iatrogenic cardiorenal syndrome leading to worsening renal function and diuretic resistance. The methods for overcoming this resistance are varied and require a focused approach with emphasis on relieving the congestive symptoms related to HF while attempting to preserve renal function and minimize any untoward systemic effects.

The cardiorenal syndrome: lessons from the ADHERE database and treatment options

Significant renal dysfunction is common in patients hospitalized for heart failure and carries a grim prognosis. Patients with heart failure who have or develop renal dysfunction while being treated for heart failure are said to have the cardiorenal syndrome. The Acute Decompensated Heart Failure National Registry (ADHERE) database, which enrolled nonselected patients admitted to the hospital for acute decompensated heart failure (ADHF), was used to determine the causes for this renal dysfunction and whether treatment can optimize outcomes. Results show that the average patient admitted for ADHF is older than those typically enrolled in clinical trials and has at least moderate kidney damage, with significantly impaired glomerular filtration rates. Renal dysfunction in patients with heart failure is complex and often multifactorial in origin, but the syndrome may be reversible in some patients. Reduction of angiotensin II levels with angiotensin-converting enzyme (ACE) inhibitors may prevent glomerular hyperfiltration and ultimately preserve renal function; however, patients who are volume-depleted may be especially sensitive to ACE inhibitor-induced efferent arteriolar dilation, so ACE inhibitor therapy in patients with renal dysfunction should be initiated when the patient is volume replete. In conclusion, impaired renal function is common in heart failure patients and may be a key cause of the cascade involving fluid retention, decompensation, and eventual hospital admission. Future pharmacologic research should focus on therapies aimed at maintaining or improving renal function in heart failure patients to reduce the high mortality associated with the cardiorenal syndrome.

Combination Therapy with Metolazone and Loop Diuretics in Outpatients with Refractory Heart Failure: An Observational Study and Review of the Literature

Metolazone is a potent thiazide-like diuretic. It is recommended in severe congestive heart failure (HF). We conducted a review of the existing literature and found that the available information on the use of metolazone in HF is based on studies containing less than 250 patients in total. Nevertheless, metolazone is widely used, often in combination with a loop diuretic. Absorption of metolazone seems to be reduced in HF. Metolazone produces a diuretic response despite a low glomerular filtration rate. A wide dose range of metolazone has been investigated (< or =2.5 to 200 mg), leaving no clear dosing recommendation. However, in most studies a low starting dose (< or =5 mg) was used. We further report an observational study on 21 patients with refractory systolic HF from our specialized outpatient HF clinic. The aim was to evaluate the effects of metolazone in combination with a loop diuretic in contemporary HF patients.

RESULTS

We registered 42 episodes of treatment with metolazone. The maximal dose of metolazone was 5 mg. NYHA functional class improved. A significant reduction during treatment in weight, blood pressure, plasma-sodium and -potassium was seen whereas plasma-BUN and -creatinine increased significantly. Clinically important hypokalemia (<2.5 mM) or hyponatremia (<125 mM) were observed during 10% of the treatment episodes.

CONCLUSION

The literature review and the observational study support the use of low-dose metolazone (< or =5 mg) on top of oral loop diuretics, as an effective and relatively safe treatment in contemporary outpatients with refractory HF.

Use of diuretics in cardiovascular diseases: (1) heart failure

Diuretics are used extensively in hospitals and in community medical practice for the management of cardiovascular diseases. They are used frequently as the first line treatment for mild to moderate hypertension and are an integral part of the management of symptomatic heart failure. Although diuretics have been used for several decades, there is still some ambiguity and confusion regarding the optimal way of using these common drugs. In this paper, the classes and action of diuretics are reviewed, and the various indications, optimal doses, and recommendations on the effective use of these agents are discussed.

Acute decompensated heart failure: a contemporary approach to pharmacotherapeutic management

Hospital admissions for acute decompensated heart failure (ADHF) have increased precipitously during the past few decades and are projected to continue to increase in the future. To optimize patient outcomes and reduce the costs associated with this disorder, evidenced-based pharmacotherapy is essential. Continuous infusions of loop diuretic therapy rather than bolus dosing may enhance efficacy and reduce the extent of diuretic resistance. Nesiritide is a pharmacologically novel preload and afterload reducer but based on clinical trial evidence should be reserved for those unable to take or with resistance to intravenous nitrate therapy. Catecholamine- and phosphodiesterase-based inotropic therapies are efficacious, but the increased risk of arrhythmogenesis and the potential for negative survival effects limit their use. The experimental agent levosimendan is a positive inotropic agent but does not increase myocyte calcium concentrations as do catecholamines or phosphodiesterase inhibitors. Clinical trial evidence demonstrates a positive survival benefit for levosimendan versus dobutamine.

Mechanisms and management of diuretic resistance in congestive heart failure

Diuretic drugs are used almost universally in patients with congestive heart failure, most frequently the potent loop diuretics. Despite their unproven effect on survival, their indisputable efficacy in relieving congestive symptoms makes them first line therapy for most patients. In the treatment of more advanced stages of heart failure diuretics may fail to control salt and water retention despite the use of appropriate doses. Diuretic resistance may be caused by decreased renal function and reduced and delayed peak concentrations of loop diuretics in the tubular fluid, but it can also be observed in the absence of these pharmacokinetic abnormalities. When the effect of a short acting diuretic has worn off, postdiuretic salt retention will occur during the rest of the day. Chronic treatment with a loop diuretic results in compensatory hypertrophy of epithelial cells downstream from the thick ascending limb and consequently its diuretic effect will be blunted. Strategies to overcome diuretic resistance include restriction of sodium intake, changes in dose, changes in timing, and combination diuretic therapy.

Metolazone and its role in edema management

Metolazone is commonly administered in conjunction with a loop diuretic to manage volume overload in patients otherwise resistant to loop diuretic therapy alone. Metolazone is a thiazide-type diuretic that is characterized by slow and sometimes erratic absorption when administered as the Zaroxylyn product. This absorptive profile together with the large volume of distribution and high degree of renal clearance for metolazone provide the pharmacologic basis for a favorable diuretic combination effect. Zaroxylyn should always be administered cautiously and only with a means of surveillance allowing the patient's weight to be carefully monitored so as to avoid excessive diuresis. If an excessive diuresis occurs with a metolazone and loop diuretic combination both drugs should be stopped temporarily. The temptation should be avoided to simply reduce the doses of either metolazone or the loop diuretic as a means to controlling an active diuresis.

[Evidence based medical treatment of heart failure]

INTRODUCTION AND OBJECTIVES

Recommendations for the treatment of heart failure were carried out by a systematic review of the available evidence of the different pharmacologic treatments.

MATERIAL AND METHODS

The review focused on the treatment of chronic and systolic heart failure. All the studies published in english about the pharmacologic treatment of heart failure where identified. The evidence of every pharmacologic treatment was classified according to: a) efficacy variables (reduction of mortality and hospitalizations, improvement of functional class, ejection fraction and exercise tolerance), and b) the level of quality of the evidence according to an evaluation scale. The evidence was also reviewed for the comparisons and the combinations of the pharmacologic treatments, as well as for the toxicity and costs of treatments.

RESULTS

The recommendations were defined according to the NYHA functional class and were classified in the A, B and C categories according to the level of quality of the available evidence. The evidence on mortality was considered the most important. First line drugs, the alternatives and other possible treatments were take into account.

CONCLUSIONS

There is enough evidence based on information about some variables such as reduction of mortality or hospitalizations to carry out treatment recommendations in all stages of heart failure. This point out the interest ant the priority of used them in the evaluation and improvement of the results of heart failure.

Drug therapy of heart failure caused by systolic dysfunction in the elderly

The presence of multiple medical illnesses often distinguishes elderly patients with heart failure and can make pharmacologic management of symptomatic heart failure challenging in this population. Physiologic changes that occur with normal aging may complicate clinical assessment. Limited data from large clinical trials of heart failure therapy are applicable to aged patients. Available data suggest that elderly patients should be treated with the same regimen as younger patients but that more careful attention should be paid to dosing, especially when initiating a new drug. History and physical examination techniques can be used to uncover evidence of congestion and inadequate perfusion and are critical adjuncts when making therapeutic decisions. The objectives of therapy for elderly patients with heart failure must be individualized within the larger context of patients' goals and stage of life.

Optimising management of patients with advanced heart failure: the importance of preventing progression

Heart failure is a highly complex, progressive and deadly disease. When incorrectly treated, it results in irreversible structural damage to the myocardium and resists any conventional treatment. This stage has been arbitrarily termed refractory heart failure. However, with timely and sufficiently applied neurohumoral antagonists, progression can be prevented, or at least delayed. In contrast, as soon as heart failure has become moderate or severe due to advanced left ventricular dysfunction, polypharmacy is the rule. Physicians should make every effort to maintain or reconsider optimal neurohumoral antagonist therapy in such patients, even if symptomatic improvement from these agents may be slow. Proper use of diuretics is essential not only for symptom relief but also to achieve full benefit from angiotensin converting enzyme inhibitors and beta-blockers. Digitalis may be particularly indicated in severe heart failure, irrespective of rhythm. Adjunctive regimens can be helpful in specific patients, but evidence of their salutary effects to prolong life is lacking. In the decompensated state, tailoring intravenous therapy to haemodynamic goals followed by (re-)institution of optimal oral therapy is an option. Only if these strategies fail is heart transplantation justified. While waiting for a donor, patients have been bridged with various intravenous agents, most often inotropes, but symptom relief is associated with risk of increased mortality due to these drugs. New hope emerges from drugs interfering with endothelin and the cytokines, and from research into increasing contractility with calcium sensitising agents. Even though these developments follow established routes, they may enable a more effective approach to prevent worsening heart failure in every single patient.

Current Concepts in the Management of Heart Failure

Objective:

To give an overview of the epidemiology, etiology, and symptoms and signs of heart failure (HF), and the role of various therapeutic modalities that influence functional status, morbidity, and mortality in HF.

Data Sources:

Computerized search of the MEDLINE database (1976–1998) and review chapters from medical textbooks.

Data Extraction:

Clinical trials evaluating the effect of drugs on morbidity and mortality of patients with HF.

Data Synthesis:

HF is a clinical syndrome with high prevalence and mortality. The treatment approach varies depending on the etiology and type of HF. Several large-scale clinical trials with angiotensin-converting enzyme (ACE) inhibitors demonstrate improved survival and reduced hospitalization in patients with all degrees of HF. Several other trials report similar benefits in postmyocardial infarction patients with HF. Angiotensin II type 1 receptor blocking agents have also been shown to reduce morbidity and mortality in elderly patients with HF and may be used in patients who cannot tolerate ACE inhibitors. Therapy with hydralazine and isosorbide dinitrate also improves exercise tolerance as well as survival in patients with HF. The combination of these agents with ACE inhibitors may be useful in patients who remain symptomatic while taking ACE inhibitors. Such second-generation dihydropyridine calcium-channel blockers as amlodipine have also been shown to improve symptoms, exercise tolerance, and survival in nonischemic patients. Diuretics are effective in reducing the symptoms of HF resulting from fluid overload. Inotropic drugs such as digoxin may improve symptoms and reduce hospitalization for patients with HF but do not reduce overall mortality. Long-term, continuous use of inotropic agents, such as amrinone, milrinone, dobutamine, and high-dose vesnarinone, may improve quality of life but increase mortality in HF. Beta-blockers, particularly Carvedilol, with vasodilating properties demonstrate positive survival results in patients with mild-to-moderate HF.

Conclusions:

ACE inhibitors are the initial drug of choice in the treatment of HF; however, angiotensin II receptor antagonists may be used in patients who are intolerant to ACE inhibitors. Diuretics are useful mainly to control the fluid overload in HF. Digoxin is helpful in patients with atrial fibrillation and rapid ventricular response and in patients who are resistant to ACE inhibitors and diuretics. Hydralazine and isosorbide dinitrate therapy is valuable in patients whose symptoms cannot be controlled with optimal doses of diuretics, digoxin, and ACE inhibitors. Careful use of newer beta-blockers, with optimal titration of diuretics, in mild-to-moderate HF may help prolong life. Newer dihydropyridine calcium-channel blockers may be beneficial in nonischemic patients with HF.