Cardiorenal interactions in acute decompensated heart failure: contemporary concepts facing emerging controversies

Novel Medical Treatments and Devices for the Management of Heart Failure with Reduced Ejection Fraction

Heart failure (HF) is a growing issue in developed countries; it is often the result of underlying processes such as ischemia, hypertension, infiltrative diseases or even genetic abnormalities. The great majority of the affected patients present a reduced ejection fraction (≤40%), thereby falling under the name of "heart failure with reduced ejection fraction" (HFrEF). This condition represents a major threat for patients: it significantly affects life quality and carries an enormous burden on the whole healthcare system due to its high management costs. In the last decade, new medical treatments and devices have been developed in order to reduce HF hospitalizations and improve prognosis while reducing the overall mortality rate. Pharmacological therapy has significantly changed our perspective of this disease thanks to its ability of restoring ventricular function and reducing symptom severity, even in some dramatic contexts with an extensively diseased myocardium. Notably, medical therapy can sometimes be ineffective, and a tailored integration with device technologies is of pivotal importance. Not by chance, in recent years, cardiac implantable devices witnessed a significant improvement, thereby providing an irreplaceable resource for the management of HF. Some devices have the ability of assessing (CardioMEMS) or treating (ultrafiltration) fluid retention, while others recognize and treat life-threatening arrhythmias, even for a limited time frame (wearable cardioverter defibrillator). The present review article gives a comprehensive overview of the most recent and important findings that need to be considered in patients affected by HFrEF. Both novel medical treatments and devices are presented and discussed.

Contemporary Decongestive Strategies in Acute Heart Failure

Congestion is the primary driver of hospital admissions in patients with heart failure and the key determinant of their outcome. Although intravenous loop diuretics remain the predominant agents used in the setting of acute heart failure, the therapeutic response is known to be variable, with a significant subset of patients discharged from the hospital with residual hypervolemia. In this context, urinary sodium excretion has gained attention both as a marker of response to loop diuretics and as a marker of prognosis that may be a useful clinical tool to guide therapy. Several decongestive strategies have been explored to improve diuretic responsiveness and removal of excess fluid. Sequential nephron blockade through combination diuretic therapy is one of the most used methods to enhance natriuresis and counter diuretic resistance. In this article, I provide an overview of the contemporary decongestive approaches and discuss the clinical data on the use of add-on diuretic therapy. I also discuss mechanical removal of excess fluid through extracorporeal ultrafiltration with a brief review of the results of landmark studies. Finally, I provide a short overview of the strategies that are currently under investigation and may prove helpful in this setting.

Development of a nomogram to predict the incidence of acute kidney injury among ischemic stroke individuals during ICU hospitalization

Background

Limited clinical prediction models exist to assess the likelihood of acute kidney injury (AKI) occurrence in ischemic stroke individuals. In this retrospective study, our aim was to construct a nomogram that utilizes commonly available clinical features to predict the occurrence of AKI during intensive care unit hospitalization among this patient population.

Methods

In this study, the MIMIC-IV database was utilized to investigate potential risk factors associated with the incidence of AKI among ischemic stroke individuals. A predictive nomogram was developed based on these identified risk factors. The discriminative performance of the constructed nomogram was assessed. Calibration analysis was utilized to evaluate the calibration performance of the constructed model, assessing the agreement between predicted probabilities and actual outcomes. Furthermore, decision curve analysis (DCA) was employed to assess the clinical net benefit, taking into account the potential risks and benefits associated with different decision thresholds.

Results

A total of 2089 ischemic stroke individuals were included and randomly allocated into developing (n = 1452) and verification cohorts (n = 637). Risk factors for AKI incidence in ischemic stroke individuals, determined through LASSO and logistic regression. The constructed nomogram had good performance in predicting the occurrence of AKI among ischemic stroke patients and provided significant improvement compared to existing scoring systems. DCA demonstrated satisfactory clinical net benefit of the constructed nomogram in both the validation and development cohorts.

Conclusions

The developed nomogram exhibits robust predictive performance in forecasting AKI occurrence in ischemic stroke individuals.

Impact of Cirrhotic Cardiomyopathy Diagnosed According to Different Criteria on Patients with Cirrhosis Awaiting Liver Transplantation: A Retrospective Cohort Study

BACKGROUND

Recently, the Cirrhotic Cardiomyopathy Consortium (Consortium) proposed criteria to replace the World Congress of Gastroenterology (WGO) criteria for cirrhotic cardiomyopathy (CCM) using contemporary echocardiography parameters. We assessed the impact of substituting WGO by Consortium criteria on the frequency of diagnosis and clinical outcomes in patients with cirrhosis awaiting liver transplantation (LT).

METHODS

Consecutive adults with cirrhosis approved for LT with echocardiography evaluation from January 2014 to December 2016 were screened. Patients with structural heart diseases were excluded. Two primary outcomes were: (1) frequency of CCM; (2) association of CCM with pre-transplant mortality. The secondary outcomes were pre-LT complications of acute kidney injury (AKI) and/or hepatic encephalopathy (HE), and post-LT mortality.

RESULTS

Of 386 patients screened, 278 were included. 238 (85.6%) and 208 (74.8%) patients met Consortium and WGO criteria, respectively; 180 (64.7%) patients fulfilled both the criteria, while 12 (4.3%) patients had no evidence of CCM by either criterion. Pre-LT mortality rates in Consortium-CCM group were similar to the other groups (19.3% vs 20.2% vs 25.0%). The patients with advanced diastolic dysfunction (DD) per Consortium-CCM criteria had higher mortality than the other groups. The rates of pre-LT AKI/HE rates and post-LT mortality were similar in Consortium-CCM and WGO-CCM groups.

CONCLUSION

The Consortium criteria do not impact the prevalence of CCM compared to WGO criteria and have similar predictive accuracy. Presence of advanced DD per the Consortium criteria increases the risk of pre-LT mortality and complications of AKI/HE. The patients with advanced DD could benefit from further monitoring and treatment.

Edema formation in congestive heart failure and the underlying mechanisms

Congestive heart failure (HF) is a complex disease state characterized by impaired ventricular function and insufficient peripheral blood supply. The resultant reduced blood flow characterizing HF promotes activation of neurohormonal systems which leads to fluid retention, often exhibited as pulmonary congestion, peripheral edema, dyspnea, and fatigue. Despite intensive research, the exact mechanisms underlying edema formation in HF are poorly characterized. However, the unique relationship between the heart and the kidneys plays a central role in this phenomenon. Specifically, the interplay between the heart and the kidneys in HF involves multiple interdependent mechanisms, including hemodynamic alterations resulting in insufficient peripheral and renal perfusion which can lead to renal tubule hypoxia. Furthermore, HF is characterized by activation of neurohormonal factors including renin-angiotensin-aldosterone system (RAAS), sympathetic nervous system (SNS), endothelin-1 (ET-1), and anti-diuretic hormone (ADH) due to reduced cardiac output (CO) and renal perfusion. Persistent activation of these systems results in deleterious effects on both the kidneys and the heart, including sodium and water retention, vasoconstriction, increased central venous pressure (CVP), which is associated with renal venous hypertension/congestion along with increased intra-abdominal pressure (IAP). The latter was shown to reduce renal blood flow (RBF), leading to a decline in the glomerular filtration rate (GFR). Besides the activation of the above-mentioned vasoconstrictor/anti-natriuretic neurohormonal systems, HF is associated with exceptionally elevated levels of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP). However, the supremacy of the deleterious neurohormonal systems over the beneficial natriuretic peptides (NP) in HF is evident by persistent sodium and water retention and cardiac remodeling. Many mechanisms have been suggested to explain this phenomenon which seems to be multifactorial and play a major role in the development of renal hyporesponsiveness to NPs and cardiac remodeling. This review focuses on the mechanisms underlying the development of edema in HF with reduced ejection fraction and refers to the therapeutic maneuvers applied today to overcome abnormal salt/water balance characterizing HF.

Phenomapping in patients experiencing worsening renal function during hospitalization for acute heart failure

Aims

The impact of worsening renal function (WRF) on the prognosis of patients with acute heart failure (AHF) remains controversial. We aimed to identify phenotypically distinct subgroups among individuals with both AHF and WRF using cluster analysis.

Methods and results

Overall, the data of 483 patients with both AHF and WRF enrolled in the West Tokyo Heart Failure Registry were analysed. Using cluster analysis, we identified three phenotypically distinct subgroups (phenogroups 1, 2, and 3). We assessed the impact of WRF on the prognosis of each phenogroup by comparing the incidence of composite endpoints, including all‐cause death and re‐hospitalization due to heart failure, with those of a propensity score‐matched, non‐WRF control group. Participants in phenogroup 1 (N = 122) were the youngest (69.3 ± 13.7 years), had relatively preserved estimated glomerular filtration rate (eGFR, 70.0 ± 27.7 mL/min/1.73 m²), and reduced left ventricular ejection fraction (LVEF) (41.8 ± 13.7%). Conversely, participants in phenogroup 3 (N = 122) were the oldest (81.7 ± 8.5 years), had the worst eGFR (33.0 ± 20.9 mL/min/1.73 m²), and had preserved LVEF (51.7 ± 14.8%). The characteristics of the participants in phenogroup 2 (N = 239) were between those of phenogroups 1 and 3. The propensity score matching analysis showed that WRF was associated with a higher incidence of composite endpoints in phenogroup 1, whereas this association was not observed in phenogroups 2 and 3.

Conclusions

Using cluster analysis, we revealed three phenotypically distinct subgroups of patients with both AHF and WRF. WRF was associated with worse clinical outcomes in the subgroup of younger patients with reduced LVEF and preserved renal function.

Variation in intraabdominal pressure in patients with acute heart failure according to left ventricular ejection fraction. Results of an intraabdominal pressure study

BACKGROUND

The increase in intraabdominal pressure (IAP) has been correlated with increased creatinine levels in patients with heart failure with severely reduced left ventricular ejection fraction (HFrEF). However, IAP has not been examined in more stable patients or those with heart failure with preserved ejection fraction (HFpEF).

PATIENTS AND METHOD

We conducted an observational, prospective descriptive study that measured the IAP of patients hospitalised for decompensated heart failure (HF). The sample was stratified according to left ventricular ejection fraction (LVEF), with a cut-off of 50%. The objective was to analyse the IAP, the baseline characteristics and degree of congestion using clinical ultrasonography and impedance audiometry.

RESULTS

The study included 56 patients, 22 with HFrEF and 34 with HFpEF. The patients with HFrEF presented a higher prevalence of ischaemic heart disease (11% vs. 6%; p = 0.010) and chronic obstructive pulmonary disease/asthma (6% vs. 2%; p = 0.025). The IAP was higher in the patients with HFrEF (17.2 vs. 13.3 mmHg; p = 0.004), with no differences in renal function at admission according to the LVEF (CKD-EPI creatinine) (HFrEF 55.0 mL/min/1.73 m² [32.6-83.6] vs. HFpEF 55.0 mL/min/1.73 m² [44.0-74.9]; p = 0.485). The patients with HFrEF presented a more congestive profile determined through ultrasonography (inferior vena cava collapse [26% vs. 50%; p = 0.001]), impedance audiometry (total body water at admission, 46 L vs. 41 L; p = 0.052; and at 72 h, 50.2 L vs. 39.1 L; p = 0.038) and CA125 concentration (68 U/mL vs. 39 U/mL; p = 0.037).

CONCLUSIONS

During the decompensation episodes, the patients with HFrEF had a greater increase in IAP and a higher degree of systemic congestion.

Acute Kidney Injury in the Patient with Cancer

Over the last three decades, advancements in the diagnosis, treatment, and supportive care of patients with cancer have significantly improved their overall survival. However, these advancements have also led to a higher rate of cancer-related complications. Acute kidney injury (AKI) and chronic kidney disease (CKD) are highly prevalent in patients with cancer, and they are associated with an increased risk of all-cause mortality. This bidirectional interplay between cancer and kidney, termed "the kidney-cancer connection" has become a very active area of research. This review aims to provide an overview of some of the most common causes of AKI in patients with cancer. Cancer therapy-associated AKI is beyond the scope of this review and will be discussed separately.

Mechanisms of kidney dysfunction in the cirrhotic patient: Non-hepatorenal acute-on-chronic kidney damage considerations

Renal dysfunction is a common finding in cirrhotic patients and has a great physiologic, and therefore, prognostic relevance. The combination of liver disease and renal dysfunction can occur as a result of systemic conditions that affect both the liver and the kidney, although primary disorders of the liver complicated by renal dysfunction are much more common. As most of the renal dysfunction scenarios in cirrhotic patients correspond to either prerenal azotemia or hepatorenal syndrome (HRS), physicians tend to conceive renal dysfunction in cirrhotic patients as mainly HRS. However, there are many systemic conditions that may cause both a "baseline" chronic kidney damage and a superimposed kidney dysfunction when this systemic condition worsens. The main aim of this article is to review some of the most important non prerenal non-HRS considerations regarding acute on chronic kidney dysfunction in cirrhotic patients, including renal manifestation of related to non-alcoholic steatohepatitis (NASH) viral hepatitis, the effect of cardiorenal syndrome in cirrhotics and corticosteroid-deficiency associated renal dysfunction.

Renal dysfunction in cardiovascular diseases and its consequences

It is well known that the heart and kidney and their synergy is essential for hemodynamic homeostasis. Since the early XIX century it has been recognized that cardiovascular and renal diseases frequently coexist. In the nephrological field, while it is well accepted that renal diseases favor the occurrence of cardiovascular diseases, it is not always realized that cardiovascular diseases induce or aggravate renal dysfunctions, in this way further deteriorating cardiac function and creating a vicious circle. In the same clinical field, the role of venous congestion in the pathogenesis of renal dysfunction is at times overlooked. This review carefully quantifies the prevalence of chronic and acute kidney abnormalities in cardiovascular diseases, mainly heart failure, regardless of ejection fraction, and the consequences of renal abnormalities on both organs, making cardiovascular diseases a major risk factor for kidney diseases. In addition, with regard to pathophysiological aspects, we attempt to substantiate the major role of fluid overload and venous congestion, including renal venous hypertension, in the pathogenesis of acute and chronic renal dysfunction occurring in heart failure. Furthermore, we describe therapeutic principles to counteract the major pathophysiological abnormalities in heart failure complicated by renal dysfunction. Finally, we underline that the mild transient worsening of renal function after decongestive therapy is not usually associated with adverse prognosis. Accordingly, the coexistence of cardiovascular and renal diseases inevitably means mediating between preserving renal function and improving cardiac activity to reach a better outcome.

Variation in intraabdominal pressure in patients with acute heart failure according to left ventricular ejection fraction. Results of an intraabdominal pressure study

BACKGROUND

The increase in intraabdominal pressure (IAP) has been correlated with increased creatinine levels in patients with heart failure with severely reduced left ventricular ejection fraction (HFrEF). However, IAP has not been examined in more stable patients or those with heart failure with preserved ejection fraction (HFpEF).

PATIENTS AND METHOD

We conducted an observational, prospective descriptive study that measured the IAP of patients hospitalised for decompensated heart failure (HF). The sample was stratified according to left ventricular ejection fraction (LVEF), with a cut-off of 50%. The objective was to analyse the IAP, the baseline characteristics and degree of congestion using clinical ultrasonography and impedance audiometry.

RESULTS

The study included 56 patients, 22 with HFrEF and 34 with HFpEF. The patients with HFrEF presented a higher prevalence of ischaemic heart disease (11% vs. 6%; p = 0.010) and chronic obstructive pulmonary disease/asthma (6% vs. 2%; p = 0.025). The IAP was higher in the patients with HFrEF (17.2 vs. 13.3 mmHg; p = 0.004), with no differences in renal function at admission according to the LVEF (CKD-EPI creatinine) (HFrEF 55.0 mL/min/1.73 m2 [32.6-83.6] vs. HFpEF 55.0 mL/min/1.73 m2 [44.0-74.9]; p = 0.485). The patients with HFrEF presented a more congestive profile determined through ultrasonography (inferior vena cava collapse [26% vs. 50%; p = 0.001]), impedance audiometry (total body water at admission, 46 L vs. 41 L; p = 0.052; and at 72 h, 50.2 L vs. 39.1 L; p = 0.038) and CA125 concentration (68 U/mL vs. 39 U/mL; p = 0.037).

CONCLUSIONS

During the decompensation episodes, the patients with HFrEF had a greater increase in IAP and a higher degree of systemic congestion.

Hepatorenal Syndrome or Hepatocardiorenal Syndrome: Revisiting Basic Concepts in View of Emerging Data

BACKGROUND

Accumulating evidence on the pathophysiology of hepatorenal syndrome has challenged the conventional model of liver-kidney connection. While liver cirrhosis is traditionally considered the origin of a cascade of pathophysiologic mechanisms directly affecting other organs such as the kidney, emerging data point to the heart as the potential mediator of the untoward renal effects.

SUMMARY

Herein, we briefly review the often-overlooked contribution of the heart to circulatory dysfunction in hepatorenal syndrome and put forward evidence arguing for the involvement of systemic inflammation and endothelial dysfunction in this setting. The temporality of cardiorenal interactions in hepatorenal syndrome and the observed beneficial effects of portosystemic shunting on these pathways lend further support to the notion that cardiac involvement plays a key role in the development of renal dysfunction in severe cirrhosis. Key Messages: The disturbances traditionally bundled within hepatorenal syndrome could represent a hepatic form of cardiorenal syndrome whereby the liver affects the kidney in part through cardiorenal pathways. This new model has practical implications and calls for a shift in the focus of diagnostic and therapeutic approaches to renal dysfunction in advanced cirrhosis.

Extracorporeal Isolated Ultrafiltration for Management of Congestion in Heart Failure and Cardiorenal Syndrome

Acute decompensated heart failure has the highest rate of hospital readmission among all medical conditions and portends a significant financial burden on health care system. Congestion, the hallmark of acute decompensated heart failure, represents the primary reason for hospitalization and the driver of adverse outcomes in these patients. Although diuretic-based medical regimens remain the mainstay of management of acute decompensated heart failure, they often show suboptimal efficacy and safety profiles in this setting. Mechanical extraction of excess fluid through extracorporeal ultrafiltration therapy has been proposed as a mechanistically relevant option in this setting. The advent of simplified, portable, and user-friendly devices that are dedicated to ultrafiltration therapy for these patients has renewed the interest in this therapeutic modality. In this article, we provide a brief overview of the initial mechanistic studies followed by the key clinical findings of the most recent landmark trials. The shortcomings of these studies are discussed in detail because not only do they provide the appropriate context in which the results are to be interpreted, but more importantly they also highlight the existing knowledge gaps that need to be addressed in future studies. Finally, selected practical and conceptual considerations and controversies are reviewed with regard to evidence-based ultrafiltration therapy.

Cardionephrology: Proposal for a Futuristic Educational Approach to a Contemporary Need

The field of cardiorenal medicine is vast, rapidly expanding, and complex. Conventional nephrology training programs provide the fellows with the necessary core knowledge to provide general care for patients with renal and cardiovascular diseases. However, there is a need for focused training of interested physicians to master the specialized aspects of these exceedingly common clinical scenarios and optimize the care of such patients. A cardionephrology-focused training can add value to the nephrology subspecialty and potentially increase its attractiveness for a significant subset of trainees. Herein, we provide a proposal for the framework and content of such an educational activity. Creation of an international multidisciplinary workgroup to formulate a comprehensive curriculum for a dedicated cardionephrology track would be the first step. A variety of practical aspects such as implementation methods, the identification of the required skills, and the development of educational assessment tools are discussed. While this proposal primarily focuses on the integration of the curriculum into the training of nephrology fellows, it would also be appropriate (albeit in a modified and customized format) for a wider range of trainees, including cardiology fellows.

Identifying novel phenotypes of acute heart failure using cluster analysis of clinical variables

BACKGROUND

Acute heart failure (AHF) is a heterogeneous disease caused by various cardiovascular (CV) pathophysiology and multiple non-CV comorbidities. We aimed to identify clinically important subgroups to improve our understanding of the pathophysiology of AHF and inform clinical decision-making.

METHODS

We evaluated detailed clinical data of 345 consecutive AHF patients using non-hierarchical cluster analysis of 77 variables, including age, sex, HF etiology, comorbidities, physical findings, laboratory data, electrocardiogram, echocardiogram and treatment during hospitalization. Cox proportional hazards regression analysis was performed to estimate the association between the clusters and clinical outcomes.

RESULTS

Three clusters were identified. Cluster 1 (n=108) represented "vascular failure". This cluster had the highest average systolic blood pressure at admission and lung congestion with type 2 respiratory failure. Cluster 2 (n=89) represented "cardiac and renal failure". They had the lowest ejection fraction (EF) and worst renal function. Cluster 3 (n=148) comprised mostly older patients and had the highest prevalence of atrial fibrillation and preserved EF. Death or HF hospitalization within 12-month occurred in 23% of Cluster 1, 36% of Cluster 2 and 36% of Cluster 3 (p=0.034). Compared with Cluster 1, risk of death or HF hospitalization was 1.74 (95% CI, 1.03-2.95, p=0.037) for Cluster 2 and 1.82 (95% CI, 1.13-2.93, p=0.014) for Cluster 3.

CONCLUSIONS

Cluster analysis may be effective in producing clinically relevant categories of AHF, and may suggest underlying pathophysiology and potential utility in predicting clinical outcomes.

Defining the role of ultrafiltration therapy in acute heart failure: a systematic review and meta-analysis

Ultrafiltration (UF) has emerged as an alternative therapy for acute decompensated heart failure (ADHF) due to its physiological benefits such as improvement in neurohormonal activation. We performed a systematic review and a meta-analysis to evaluate the efficacy, safety, and the impact on outcomes for UF therapy as compared to conventional medical treatment. The PubMed and Cochrane databases were searched from inception to December 2015 for randomized controlled trials that examined UF therapy in ADHF and used diuretic-based regimens as the control group. In accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, we explored the impact on weight change, fluid removal, renal function, rehospitalization rate, and mortality. Mantel-Haenszel odds ratio (OR) was calculated for dichotomous data and weighted mean difference (WMD) for continuous data. Seven studies with a total of 771 patients met our selection criteria. UF therapy led to greater weight loss (WMD 1.35, 95 % CI 0.49-2.21, p < 0.01) and fluid removal (WMD 1.81, 95 % CI 1.01-2.62, p = <0.01) while the impact of UF on renal function was comparable with medical treatment (WMD 0.06, 95 % CI -0.11 to 0.22, p = 0.48), UF decreased heart failure rehospitalization rate (OR 0.60, 95 % CI 0.37-0.98, p = 0.04) but did not change mortality (OR 1.03, 95 % CI 0.68-1.57, p = 0.89). Compared with diuretic-based medical treatment, UF therapy is more efficient in decongestion of patients with ADHF. It does not have a deleterious impact on renal function and can improve heart failure-related rehospitalization rate, albeit without conferring a survival benefit.

Fluid overload as a major target in management of cardiorenal syndrome: Implications for the practice of peritoneal dialysis

Congestion is an integral component of cardiorenal syndrome and portends an adverse impact on the outcomes. Recent studies suggest that congestion has the ability of modulating the interactions between the kidney and the heart in this setting. Peritoneal dialysis (PD) is a home-based therapeutic modality that is not only offered to patients with end-stage renal disease to provide solute clearance and ultrafiltration, but it has also been used in patients with refractory heart failure and fluid overload to help optimize volume status. Several uncontrolled studies and case series have so far evaluated the role of PD in management of hypervolemia for patients with heart failure. They have generally reported favorable results in this setting. However, the data on the outcomes of patients with end-stage renal disease and concomitant heart failure is mixed, and the proposed theoretical advantages of PD might not translate into improved clinical endpoints. Congestion is prevalent in this patient population and has a significant effect on their survival. As studies suggest that a significant subset of patients with end-stage renal disease who receive PD therapy are hypervolemic, suboptimal management of congestion could at least in part explain these conflicting results. PD is a highly flexible therapeutic modality and the choice of techniques, regimens, and solutions can affect its ability for optimization of fluid status. This article provides an overview of the currently available data on the role and clinical relevance of congestion in patients with cardiorenal syndrome and reviews potential options to enhance decongestion in these patients.

An Isoform of Nedd4-2 Plays a Pivotal Role in Electrophysiological Cardiac Abnormalities

We have previously shown that neural precursor cell-expressed developmentally downregulated gene 4-2 (Nedd4-2) isoforms with a C2 domain are closely related to ubiquitination of epithelial sodium channel (ENaC), resulting in salt-sensitive hypertension by Nedd4-2 C2 targeting in mice. The sodium voltage-gated channel alpha subunit 5 (SCN5A) gene encodes the α subunit of the human cardiac voltage-gated sodium channel (I Na), and the potassium voltage-gated channel subfamily H member 2 (KCNH2) gene encodes rapidly activating delayed rectifier K channels (I Kr). Both ion channels have also been shown to bind to Nedd4-2 via a conserved Proline-Tyrosine (PY) motif in C-terminal with subsequent ubiquitination and degradation by proteasome. Therefore, loss of Nedd4-2 C2 isoform might be involved in electrophysiological impairment under various conditions. We demonstrate here that Nedd4-2 C2 isoform causes cardiac conduction change in resting condition as well as proarrhythmic change after acute myocardial infarction (MI). The Nedd4-2 C2 knockout (KO) mice showed bradycardia, prolonged QRS, QT intervals, and suppressed PR interval in resting condition. In addition, enhancement of T peak/T end interval was found in mice with surgical ligation of the distal left coronary artery. Morphological analyses based on both ultrasonography of the living heart, as well as histopathological findings revealed that Nedd4-2 C2 KO mice show no significant structural changes from wild-type littermates under resting conditions. These results suggested that Nedd4-2 with C2 domain might play an important role in cardio-renal syndrome through post-transcriptional modification of both ENaC and cardiac ion channels, which are critical for kidney and heart functions.

Involvement of systemic venous congestion in heart failure

Systemic venous congestion has gained significant importance in the interpretation of the pathophysiology of acute heart failure, especially in the development of renal function impairment during exacerbations. In this study, we review the concept, clinical characterisation and identification of venous congestion. We update current knowledge on its importance in the pathophysiology of acute heart failure and its involvement in the prognosis. We pay special attention to the relationship between abdominal congestion, the pulmonary interstitium as filtering membrane, inflammatory phenomena and renal function impairment in acute heart failure. Lastly, we review decongestion as a new therapeutic objective and the measures available for its assessment.

Ultrafiltration Therapy for Heart Failure: Balancing Likely Benefits against Possible Risks

Heart failure remains a major public health concern because of its high prevalence, morbidity, mortality, and financial burden. The poor clinical outcomes associated with acute decompensated heart failure, suboptimal efficacy and safety profile of conventional treatment regimens, and unsatisfactory experiences with the newer classes of pharmacologic therapy underlie the interest in the use of extracorporeal isolated ultrafiltration in this setting. In this article, selected mechanistic aspects of ultrafiltration therapy are briefly reviewed followed by a critical overview of the largest trials in this field. I will discuss the clinical relevance of renal dysfunction and decongestion as two commonly used end points of safety and efficacy in the ultrafiltration trials, with emphasis on the emerging pertinent notions that could challenge our conventional thinking. Finally, a number of practical recommendations (e.g., customization of ultrafiltration rates) are provided for ultrafiltration therapy in the setting of acute decompensated heart failure. Because of a paucity of evidence, universally accepted consensus guidelines cannot yet be generated. As such, when considering ultrafiltration therapy for acute decompensated heart failure, the likely benefits should be carefully balanced against the potential risks for an individual patient. A conceivable implication of the ultrafiltration trials is that collaborative heart failure programs benefiting from nephrology expertise and resources could improve the outcomes and reduce the cost.

"AVOID"ing harm by a double-edged sword: is there a role for ultrafiltration in heart failure?

Prior studies comparing ultrafiltration with medical management for acute decompensated heart failure have yielded conflicting results. The AVOID-HF trial was designed as a definitive comparison of optimal ultrafiltration versus optimal diuretic-based medical therapy; unfortunately, the trial was terminated prematurely because of slow recruitment. The results of AVOID-HF nevertheless provide a rationale for well-designed, adequately powered trials to determine whether ultrafiltration has a role in the routine management of acute decompensated heart failure.

Extracorporeal ultrafiltration therapy for acute decompensated heart failure

Congestion is the most common reason for hospitalization of patients with acute decompensated heart failure (ADHF) and adversely impacts their outcomes. Extracorporeal ultrafiltration (UF) therapy has re-emerged as an effective strategy for decongestion in this setting. This article is intended to discuss key concepts in UF and its technique, provide a brief historical view of UF application for decongestion in ADHF, review the hemodynamic and neurohormonal effects of UF and their positive effects on the pathophysiology of ADHF, discuss the findings of the landmark trials in this field, and explain key findings of these studies as well as the apparent discrepancies in their findings. In a separate section we discuss the intricacies of renal dysfunction in ADHF as it plays a very important role in understanding the current evidence and designing futures clinical trials of UF in ADHF. In the end, the authors provide their perspective on the future role of UF in management of patients with ADHF and congestion.

Pathophysiology of acute heart failure: a world to know

Our understanding of the pathophysiological mechanisms of heart failure (HF) has changed considerably in recent years, progressing from a merely haemodynamic viewpoint to a concept of systemic and multifactorial involvement in which numerous mechanisms interact and concatenate. The effects of these mechanisms go beyond the heart itself, to other organs of vital importance such as the kidneys, liver and lungs. Despite this, the pathophysiology of acute HF still has aspects that elude our deeper understanding. Haemodynamic overload, venous congestion, neurohormonal systems, natriuretic peptides, inflammation, oxidative stress and its repercussion on cardiac and vascular remodelling are currently considered the main players in acute HF. Starting with the concept of acute HF, this review provides updates on the various mechanisms involved in this disease.

Effect of estimated plasma volume reduction on renal function for acute heart failure differs between patients with preserved and reduced ejection fraction

BACKGROUND

The prognostic relevance of plasma volume reduction (PVR) in acute heart failure patients remains unclear because of the confounding hemodynamic effect of left ventricular ejection fraction impairment on kidney function.

METHODS AND RESULTS

Subjects enrolled in the West Tokyo Heart Failure Registry were examined. The PV at admission and discharge was estimated from the subjects' body weight and its deviation from the ideal body weight. Patients in the top tertile of estimated PVR were classified as PVR+. Of the 381 patients with acute heart failure, 181 (47.5%) had heart failure with preserved ejection fraction (HFpEF). Estimated PVR was associated with worsening renal function in the HFpEF (odds ratio, 3.28; 95% confidence interval, 1.55-6.96; P=0.002) but not in the heart failure with reduced ejection fraction cohort (odds ratio, 1.22; 95% confidence interval, 0.61-2.42; P=0.57). This association in the HFpEF cohort remained significant after adjusting for a history of hypertension and diabetes mellitus and the estimated glomerular filtration rate (odds ratio, 3.34; 95% confidence interval, 1.52-7.33; P=0.003). The use of intravenous diuretics was a significant predictor of PVR in the HFpEF and heart failure with reduced ejection fraction groups.

CONCLUSIONS

The effect of estimated PVR differs by HF type, and the estimated PVR during hospitalization is a predictor of worsening renal function in patients with HFpEF but not in heart failure with reduced ejection fraction.

CLINICAL TRIAL REGISTRATION

URL: http://www.umin.ac.jp/ctr/index-j.html. Unique identifier: UMIN000001549.

Pathogenesis and clinical presentation of acute heart failure

Acute heart failure constitutes a heterogeneous clinical syndrome, whose pathophysiology is complex and not completely understood. Given the diversity of clinical presentations, several different pathophysiological mechanisms along with factors triggering circulatory decompensation are involved. This article discusses the available evidence on the pathophysiological phenomena attributed or/and associated with episodes of acute heart failure and describes different clinical profiles, which, from a clinical perspective, constitute a key element for therapeutic decision-making.