Ultrafiltration should not replace diuretics for the initial treatment of acute decompensated heart failure

Continuation of Angiotensin Converting Enzyme Inhibitors in Acute Heart Failure

Purpose

The aim of this study was to show whether blocking the deleterious effects of neurohormonal activation from furosemide by the use of ACEI/ARBs, or the improvement of renal perfusion by using these drugs allows better diuresis and renal function preservation.

Patients and Methods

This is a prospective, randomized study in which patients with chronic heart failure were included. Patients admitted for ACEI/ARBs maintenance with acute decompensated HF were added in the study. The patients were divided into two groups: group 1 had ACEI/ARBs continued during admission and group 2 had stopped taking them. Patients with acute heart failure were provided with angiotensin II receptor blockers. Therefore, the present study aims to differentiate between the uses of ACEI/ARBs blocking the deleterious effects of neurohormonal activation or the improvement of renal perfusion by holding these drugs to allow better diuresis and renal function preservation in a young population.

Results

The results showed that the mean age of 32 patients of group 1 was 58±15.3 and for group 2 56±15.6. On day of analysis, BP was 113/65±11.9/6.5 and 108/66.9±14.1/9.8, weight was 68.4±19.8 kg and 73.7±20.2 kg, net volume balance of urine output was 2810.3±1011.8 mL and 3941.7±2849.7 mL, and length of stay was 11.75±6 and 7.9±3.7 days for groups 1 and 2, respectively. There was no significant difference in SBP (p=0.2926), DBP (p=0.7369), weight (p=0.4798), glomerular filtration rate (GFR) (p=0.7), and volume balance (p=0.166). However, there was statistically significant difference in length of hospital stay (p=0.0392).

Conclusion

The study concluded that continuing ACEI/ARBs or holding them during IV diuresis had no difference in the effect on kidney function or diuresis. Length of stay appears to be shorter for those who held their ACEI/ARBs.

Focus on renal congestion in heart failure

Hospitalizations due to heart failure are increasing steadily despite advances in medicine. Patients hospitalized for worsening heart failure have high mortality in hospital and within the months following discharge. Kidney dysfunction is associated with adverse outcomes in heart failure patients. Recent evidence suggests that both deterioration in kidney function and renal congestion are important prognostic factors in heart failure. Kidney congestion in heart failure results from low cardiac output (forward failure), tubuloglomerular feedback, increased intra-abdominal pressure or increased venous pressure. Regardless of the cause, renal congestion is associated with increased morbidity and mortality in heart failure. The impact on outcomes of renal decongestion strategies that do not compromise renal function should be explored in heart failure. These studies require novel diagnostic markers that identify early renal damage and renal congestion and allow monitoring of treatment responses in order to avoid severe worsening of renal function. In addition, there is an unmet need regarding evidence-based therapeutic management of renal congestion and worsening renal function. In the present review, we summarize the mechanisms, diagnosis, outcomes, prognostic markers and treatment options of renal congestion in heart failure.

Should we extend the application of more frequent dialysis schedules? A 'yes' and a hopeful 'no'

Observational studies associate long dialysis intervals with an excess risk for mortality and cardiovascular disease hospitalizations. The application alternate day dialysis is an appealing possibility to reduce the cardiovascular burden of long dialysis intervals and a small pilot study demonstrated that this regimen allows safe reduction of dry body weight, BP and left ventricular mass index. However, the actual impact of alternate day hemodialysis and of frequent hemodialysis in general on survival remains unknown. Frequent dialysis schedules may increase the risk of arteriovenous fistula problems and the burden of disease and eventually reduce treatment adherence. Furthermore we cannot safely exclude that more frequent dialysis regimens may be harmful. On the other hand increasing the duration of dialysis and/or frequency of hemodialysis in patients with refractory fluid overload, uncontrolled hypertension, hyperphosphatemia, malnutrition or cardiovascular disease is of unquestionable benefit in these problematic patients.Thus the moderators conclusion to the question being asked is a yes and a hopeful "no". Whenever and wherever possible we should pro-actively apply more frequent dialysis regimens, starting with the alternate day approach, in problematic patients. However, extensive application of frequent hemodialysis schedules is by now unjustified. Evidence that these regimens are beneficial mainly derives from observational studies and the possibility that frequent schedules are harmful cannot be excluded. A clinical trial is needed.

Pathophysiology of cardiorenal syndrome in decompensated heart failure: role of lung-right heart-kidney interaction

Cardiorenal syndrome (CRS) is defined as an interaction of cardiac disease with renal dysfunction that leads to diuretic resistance and renal function worsening, mainly with heart failure (HF) exacerbation. Hemodynamic variables linking heart and kidney are renal blood flow (cardiac output) and perfusion pressure, i.e., the aortic - renal venous pressure gradient. CRS has traditionally been interpreted as related to defective renal perfusion and arterial underfilling and, more recently, to elevation in central venous pressure transmitted back to renal veins. Our suggestion is that in a setting where aortic pressure is generally low, due to heart dysfunction and to vasodrepressive therapy, the elevated central venous pressure (CVP) contributes to lower the renal perfusion pressure below the threshold of kidney autoregulation (≤80mm Hg) and causes renal perfusion to become directly pressure dependent. This condition is associated with high neurohumoral activation and preglomerular vasoconstriction that may preserve pressure, but may decrease filtration fraction and glomerular filtration rate and enhance proximal tubular sodium absorption. Thus, congestion worsens and drives the vicious cycle of further sodium retention and HF exacerbation. Lowering CVP by targeting the lung-right heart interaction that sustains elevated CVP seems to be a more rational approach rather than reducing intravascular volume. This interaction is crucial and consists of a cascade with stepwise development of pulmonary post-capillary hypertension, precapillary arteriolar hypertone, right ventricular overload and enlargement with tricuspid incompetence and interference with left ventricular filling (interdependence). The resultant CVP rise is transmitted to the renal veins, eventually drives CRS and leads to a positive feedback loop evolving towards HF refractoriness.

Fluid management strategies in heart failure

In patients with chronic heart failure, fluid retention (or hypervolemia) is often the stimulus for acute decompensated heart failure that requires hospitalization. The pathophysiology of fluid retention is complex and involves both hemodynamic and clinical congestion. Signs and symptoms of both hemodynamic and clinical congestion should be assessed serially during hospitalization. Core heart failure drug and cardiac device therapies should be provided, and ultrafiltration may be warranted. Critical care, intermediate care, and telemetry nurses have roles in both assessment and management of patients hospitalized with acute decompensated heart failure and fluid retention. Nurse administrators and managers have heightened their attention to fluid retention because the Medicare performance measure known as the risk-standardized 30-day all-cause readmission rate after heart failure hospitalization can be attenuated by fluid management strategies initiated by nurses during a patient's hospitalization.

Cardiorenal syndrome in acute decompensated heart failure

Cardiorenal syndrome (CRS) commonly occurs during treatment of acute decompensated heart failure (ADHF) and is associated with poor clinical outcome. The pathophysiology of CRS entails a complex interaction between hemodynamic alterations, including reduced renal perfusion, increased venous pressure and activation of multiple neurohormonal systems. Attempts to effectively treat congestion while preserving renal function in ADHF are often met with limited clinical success and often require therapeutic decisions that reflect a compromise between potential benefits and harm. At present, there is no evidence-based intervention specifically targeted at renal function. Recent Phase III randomized trials, using novel agents in patients with ADHF, have largely failed to demonstrate any benefits of therapy on renal and clinical outcomes. Early diagnosis of CRS using novel markers of tubular injury may allow for timely interventions and attenuate progression. Future studies are needed to further elucidate the pathophysiology of this complex syndrome and identify new potential targets for effective evidence-based treatments.

Targeting hyponatremia and hemodynamics in acute decompensated heart failure: is there a role for vasopressin antagonists?

Current treatment of acute decompensated heart failure (ADHF) has not reduced the significant morbidity or mortality associated with this disease, and has promoted drug development aimed at neurohormonal targets. Hypervolemic hyponatremia, which is linked to the nonosmotic release of arginine vasopressin, is associated with a poor prognosis in patients with heart failure (HF). Vasopressin acts on V(2) and V(1a) receptors to cause water retention and vasoconstriction, respectively. Clinical trials have demonstrated that vasopressin receptor antagonists (VRAs) are effective in treating hypervolemic hyponatremia in ADHF without a negative impact on renal function. The small hemodynamic benefit seen with VRA use appeared to result from V(2)-receptor antagonist-induced increase in urine output rather than from a vasodilatory drug effect. VRA use in ADHF trials was associated with minimal symptomatic improvement and no impact on morbidity or mortality. At present, clinical trial evidence does not support the routine use of VRAs in ADHF. Given the favorable renal profile of VRAs, studies on the possible benefit of VRAs in ADHF patients with renal insufficiency and diuretic resistance appear warranted.

Decongestive treatment of acute decompensated heart failure: cardiorenal implications of ultrafiltration and diuretics

In patients with acute decompensated heart failure (ADHF), treatment aimed at adequate decongestion of the volume overloaded state is essential. Despite diuretic therapy, many patients remain volume overloaded and symptomatic. In addition, adverse effects related to diuretic treatment are common, including worsening kidney function and electrolyte disturbances. The development of decreased kidney function during treatment affects the response to diuretic therapy and is associated with important clinical outcomes, including mortality. The occurrence of diuretic resistance and the morbidity and mortality associated with diuretic therapy has stimulated interest to develop effective and safe treatment strategies that maximize decongestion and minimize decreased kidney function. During the last few decades, extracorporeal ultrafiltration has been used to remove fluid from diuretic-refractory hypervolemic patients. Recent clinical studies using user-friendly machines have suggested that ultrafiltration may be highly effective for decongesting patients with ADHF. Many questions remain regarding the comparative impact of diuretics and ultrafiltration on important clinical outcomes and adverse effects, including decreased kidney function. This article serves as a summary of key clinical studies addressing these points. The overall goal is to assist practicing clinicians who are contemplating the use of ultrafiltration for a patient with ADHF.

The challenge of treating congestion in advanced heart failure

Volume overload is a common manifestation of heart failure decompensation. Interaction between impaired renal and heart function constitutes an important pathophysiologic mechanism that leads to congestion. In addition to improving symptoms and volume status, reduction of rehospitalization rates, maintenance of renal function and improvement of survival are all important goals of every therapeutic strategy. Currently, the use of diuretics, vasodilators, inotropes and ultrafiltration, together with investigational agents such as oral vasopressin antagonists and adenosine A1-receptor antagonists, constitute the main therapeutic options for the congested heart failure patient.

The complexity of the cardio-renal link: taxonomy, syndromes, and diseases

Bidirectional mechanisms exist that link diseases affecting the heart and kidney. This link is complex and remains poorly understood; therefore, charting the shared territory of cardiovascular (CV) and renal medicine poses major problems. Until now, no convincing rationale for delineating new syndromes existed. The multiple connections of the arterial system and the heart and kidney with other systems, from energy and protein balance to the musculoskeletal, clearly require special focus and rigorous framing. Nephrologists have yet to fully understand why the application of dialysis has had only limited success in halting the parallel burdens of CV and non-CV death in patients with end-stage renal disease. Cardiologists, intensivists, and nephrologists alike should settle whether and when extracorporeal ultrafiltration benefits patients with decompensated heart failure. These sparse but interconnected themes spanning from the basic science-clinical transition phase to clinical science, epidemiology, and medical technology already form the basis for the young discipline of 'CV and renal medicine'.

Ultrafiltration in heart failure

Fluid overload is a key pathophysiologic mechanism underlying both the acute decompensation episodes of heart failure and the progression of the syndrome. Moreover, it represents the most important factor responsible for the high readmission rates observed in these patients and is often associated with renal function worsening, which by itself increases mortality risk. In this clinical context, ultrafiltration (UF) has been proposed as an alternative to diuretics to obtain a quicker relief of pulmonary/systemic congestion. This review illustrates technical issues, mechanisms, efficacy, safety, costs, and indications of UF in heart failure. The available evidence does not support the widespread use of UF as a substitute for diuretic therapy. Owing to its operative characteristics, UF cannot be expected to directly influence serum electrolyte levels, azotemia, and acid-base balance, or to remove high-molecular-weight substances (eg, cytokines) in clinically relevant amounts. Ultrafiltration should be used neither as a quicker way to achieve a sort of mechanical diuresis nor as a remedy for an inadequately prescribed and administered diuretic therapy. Instead, it should be reserved to selected patients with advanced heart failure and true diuretic resistance, as part of a more complex strategy aiming at an adequate control of fluid retention.

Need for a unified decision-making tool for ultrafiltration therapy in heart failure; call for action

Although ultrafiltration portends several theoretical advantages over the standard therapy for acute decompensated heart failure, it might not be the optimal treatment for all patients presenting with an episode of decompensation. It is not yet clear how to prospectively identify the subset of patients that would benefit from this therapeutic modality. Based on the pathophysiologic mechanisms underlying acute decompensated heart failure, early ultrafiltration therapy can be an appropriate initial management strategy for those patients with diuretic resistance whose associated renal dysfunction is related to hemodynamic changes rather than a structural abnormality. In the absence of widely accepted consensus guidelines, ultrafiltration use is currently subject to considerable variations among physicians. A clinical tool (eg, a scoring system) that is based on the individual patient's characteristics is therefore needed to prospectively identify the appropriate candidates for this therapy. Using this system is likely to portend better outcomes while helping to avoid unnecessary exposure to potential risks of extracorporeal therapies.