Discordance Between Hemoconcentration and Clinical Assessment of Decongestion in Acute Heart Failure

The interstitial compartment as a therapeutic target in heart failure

Congestion is the single most important contributor to heart failure (HF) decompensation. Most of the excess volume in patients with HF resides in the interstitial compartment. Inadequate decongestion implies persistent interstitial congestion and is associated with worse outcomes. Therefore, effective interstitial decongestion represents an unmet need to improve quality of life and reduce clinical events. The key processes that underlie incomplete interstitial decongestion are often ignored. In this review, we provide a summary of the pathophysiology of the interstitial compartment in HF and the factors governing the movement of fluids between the interstitial and vascular compartments. Disruption of the extracellular matrix compaction occurs with edema, such that the interstitium becomes highly compliant, and large changes in volume marginally increase interstitial pressure and allow progressive capillary filtration into the interstitium. Augmentation of lymph flow is required to prevent interstitial edema, and the lymphatic system can increase fluid removal by at least 10-fold. In HF, lymphatic remodeling can become insufficient or maladaptive such that the capacity of the lymphatic system to remove fluid from the interstitium is exceeded. Increased central venous pressure at the site of the thoracic duct outlet also impairs lymphatic drainage. Owing to the kinetics of extracellular fluid, microvascular absorption tends to be transient (as determined by the revised Starling equation). Therefore, effective interstitial decongestion with adequate transcapillary plasma refill requires a substantial reduction in plasma volume and capillary pressure that are prolonged and sustained, which is not always achieved in clinical practice. The critical importance of the interstitium in the congestive state underscores the need to directly decongest the interstitial compartment without relying on the lowering of intracapillary pressure with diuretics. This unmet need may be addressed by novel device therapies in the near future.

Multimodal Strategies for the Diagnosis and Management of Refractory Congestion. An Integrated Cardiorenal Approach

Refractory congestion is common in acute and chronic heart failure, and it significantly impacts functional class, renal function, hospital admissions, and survival. In this paper, the pathophysiological mechanisms involved in cardiorenal syndrome and the interplay between heart failure and chronic kidney disease are reviewed. Although the physical exam remains key in identifying congestion, new tools such as biomarkers or lung, vascular, and renal ultrasound are currently being used to detect subclinical forms and can potentially impact its management. Thus, an integrated multimodal diagnostic algorithm is proposed. There are several strategies for treating congestion, although data on their efficacy are scarce and have not been validated. Herein, we review the optimal use and monitorization of different diuretic types, administration route, dose titration using urinary volume and natriuresis, and a sequential diuretic scheme to achieve a multitargeted nephron blockade, common adverse events, and how to manage them. In addition, we discuss alternative strategies such as subcutaneous furosemide, hypertonic saline, and albumin infusions and the available evidence of their role in congestion management. We also discuss the use of extracorporeal therapies, such as ultrafiltration, peritoneal dialysis, or conventional hemodialysis, in patients with normal or impaired renal function. This review results from a multidisciplinary view involving both nephrologists and cardiologists.

Worsening renal function in acute heart failure in the context of diuretic response

Background

For patients with acute heart failure (AHF), substantial diuresis after administration of loop diuretics is generally associated with better clinical outcomes but may cause creatinine to rise, suggesting renal function decline. We investigated the interaction between diuretic response and worsening renal function (WRF) on clinical outcomes in patients with AHF.

Methods and results

In two AHF cohorts (PROTECT, n = 1698 and RELAX‐AHF‐2, n = 5586 in current analysis), the prognostic impact of WRF (creatinine ≥0.3 mg/dl increase baseline—day 4; sensitivity analyses incorporated baseline renal function) by diuretic response (kg weight loss/40 mg furosemide equivalent baseline—day 4) was investigated with regard to (cardiovascular) death or cardiovascular/renal hospitalization using subpopulation treatment effect pattern plots (STEPP) and survival analyses. WRF occurred in 286 (16.8%) and 1031 (18.5%) patients in PROTECT and RELAX‐AHF‐2, respectively. Patients with WRF had higher left ventricular ejection fraction and lower estimated glomerular filtration rate at baseline (p < 0.05), and received higher doses of loop diuretics and had a worse diuretic response (p < 0.001). In patients with a poor diuretic response (≤0.35 kg weight loss/40 mg furosemide equivalent as identified by STEPP), WRF was associated with higher risk of (cardiovascular) death or cardiovascular/renal hospitalization (p < 0.001 both cohorts), but this was not the case for patients with a good diuretic response (p = 0.900 both cohorts).

Conclusion

In two large cohorts of patients with AHF, WRF in the first 4 days was not associated with worse outcomes when patients had a good diuretic response. The occurrence of WRF in patients with AHF should therefore be considered in the context of diuretic response.

Chloride in Heart Failure Syndrome: Its Pathophysiologic Role and Therapeutic Implication

Until recently, most studies of heart failure (HF) focused on body fluid dynamics through control of the sodium and water balance in the body. Chloride has remained largely ignored in the medical literature, and in clinical practice, chloride is generally considered as an afterthought to the better-known electrolytes of sodium and potassium. In recent years, however, the important role of chloride in the distribution of body fluid has emerged in the field of HF pathophysiology. Investigation of HF pathophysiology according to the dynamics of serum chloride is rational considering that chloride is an established key electrolyte for tubulo-glomerular feedback in the kidney and a possible regulatory electrolyte for body fluid distribution. The present review provides a historical overview of HF pathophysiology, followed by descriptions of the recent attention to the electrolyte chloride in the cardiovascular field, the known role of chloride in the human body, and recent new findings regarding the role of chloride leading to the proposed ‘chloride theory’ hypothesis in HF pathophysiology. Next, vascular and organ congestion in HF is discussed, and finally, a new classification and potential therapeutic strategy are proposed according to the ‘chloride theory’.

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.

Estimated plasma volume status in heart failure: clinical implications and future directions

Congestion is one of the main predictors of poor outcome in patients with heart failure (HF). Assessing and monitoring congestion is essential for optimizing HF therapy. Among the various available methods, serial measurements of estimated plasma volume (ePVS) using routine blood count and/or body weight (e.g., the Strauss, Duarte, Hakim formulas) may be useful in HF management. Further prospective study is warranted to determine whether ePVS can help optimize decongestion therapy (loop diuretics, mineralocorticoid receptor antagonists, SGLT2i) in various HF settings. This narrative review summarizes the recent evidence supporting the association of ePVS with clinical congestion and outcome(s) and discusses future directions for monitoring ePVS in HF.

Proposal for New Classification and Practical Use of Diuretics According to Their Effects on the Serum Chloride Concentration: Rationale Based on the "Chloride Theory"

Currently, diuretic therapy for heart failure (HF) pathophysiology is primarily focused on the sodium and water balance. Over the last several years, however, chloride (Cl) has been recognized to have an important role in HF pathophysiology, as both a prognostic marker and a possible central factor regulating the body fluid status. I recently proposed a unifying hypothesis for HF pathophysiology, called the "chloride theory", during HF worsening and recovery, as follows. Chloride is the key electrolyte for regulating both reabsorption of tubular electrolytes and water in the kidney through the renin-angiotensin-aldosterone system and distributing body fluid in each compartment of the body. As changes between the serum Cl concentration and plasma volume are intimately associated with worsening HF and its recovery after decongestive therapy, modulation of the serum Cl concentration by careful selection and combination of various diuretics and their doses could become an attractive therapeutic option for HF. In this review, I will propose a new classification and practical use of diuretics according to their effects on the serum Cl concentration. Diuretic use according to this classification is expected to be a useful strategy for the treatment of patients with HF.

Relation between Hemoconcentration Status and Readmission Plus Mortality Rate Among Iranian Individuals with Decompensated Heart Failure

BACKGROUND

Hemoconcentration (HC) has been suggested to be a useful biomarker for determination of optimum diuretic therapy in acute heart failure (HF), but role of this factor in rehospitalization and death was still controversial. In this study, we aimed to define relation between HC and readmission and mortality rate among Iranian patients with acute HF.

METHODS

This was a prospective cohort study done from March 2017 to March 2018 using data of a HF section of Persian Registry Of cardioVascular diseasE. From a total number of 390 registered HF individuals aged 18 years or older, 69 ones showed alterations in hemoglobin (Hb) levels. Hb levels were measured at admission and discharge time. HC was defined as any increased level in Hb during hospitalization. The relation of HC with readmission and death rate was done using multiple logistic regression and Cox proportional hazard model, respectively.

RESULTS

The mean age of study population was 70.5 ± 11.9 years with the dominant percentage of male participants (66.9%). Patients showing HC during admission did not reveal any significant decreased likelihood of rehospitalization compared to negative ones. In comparison to HC negative patients, those showing increments in Hb levels had a borderline significant lower likelihood of mortality (hazard ratio: 0.82, 95% confidence interval, CI = 0.07-1.18, P = 0.08).

CONCLUSIONS

Our data suggested that HC was associated marginally with reduced mortality rate 6 months post HF attack and could be utilized as a useful biomarker for risk stratification of HF patients. Several prospective longitudinal population-based studies are necessary proving these associations.

Worsening renal function during decongestion among patients hospitalized for heart failure: Findings from the Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness (ESCAPE) trial

INTRODUCTION

Worsening renal function (WRF) can occur throughout a hospitalization for acute heart failure (HF). However, decongestion can be measured in different ways and the prognostic implications of WRF in the setting of different measures of decongestion are unclear.

METHODS

Patients (N = 433) from the ESCAPE were classified by measures of decongestion during hospitalization: hemodynamic (right atrial pressure ≤8 mmHg and/or wedge pressure ≤15 mmHg at discharge), clinical (≤1 sign of congestion at discharge), hemoconcentration (any increase in hemoglobin) and estimated plasma volume using the Hakim formula (5% reduction in plasma volume). WRF was defined as creatinine increase ≥0.3 mg/dl during hospitalization. The association between WRF and 180-day all-cause death was assessed.

RESULTS

Successful decongestion was observed in 124 (60%) patients by hemodynamics, 204 (49%) by clinical exam, 173 (47%) by hemoconcentration, and 165 (45%) by plasma volume. There was no agreement between the hemodynamic assessment and other decongestion measures in up to 43% of cases. Persistent congestion with concomitant WRF at discharge was associated with worse outcomes compared to patients without congestion and WRF. Among patients decongested at discharge, in-hospital WRF was not significantly associated with 180-day all-cause death, when using hemodynamic, clinical or estimated plasma volume as measures of decongestion (P > .05 for all markers).

CONCLUSIONS

In patients hospitalized for HF, although there was disagreement across common measures of decongestion, in-hospital WRF was not associated with increased hazard of all-cause mortality among patients successfully decongested at discharge.

Evaluation of Subclinical Fluid Overload Using Lung Ultrasound and Estimated Plasma Volume in the Postoperative Period Following Kidney Transplantation

AIM

B-lines count measured with lung ultrasound (LUS) quantifies extravascular lung water and is validated in the setting of acute cardiac failure or chronic dialysis. Patients are often kept in moderately overhydrated states during the early postoperative period following kidney transplantation (KT). We described congestion changes during the early postoperative period following KT and the feasibility of LUS in this setting.

METHODS

LUS (28 scanning-points method) and inferior vena cava (IVC) measurements were routinely performed in 36 patients after KT. Estimated plasma volume (ePV) was calculated from hemoglobin and hematocrit levels.

RESULTS

No patient had >15 B-lines during the hospital stay. B-lines slightly increased until Day 4 after KT (Day 1, 1.7 ± 1.7; Day 4, 2.5 ± 2.5) and decreased up to Day 10 (1.4 ± 2.2; P vs Day 4 <.05). More B-lines were observed in patients aged older than 60 (P = .01 at Day 4) whereas IVC diameter and ePV were similar. In patients older than 60, B-lines had weak correlation with body weight variation (r = 0.64; P < .05), IVC diameters (r = 0.59 at Day 4 and r = 0.58 at Day 10; P < .05) but a strong correlation with ePV (r = 0.93 at Day 14; P < .05). B-line changes from Day 1 to Day 10 correlated with IVC diameter changes (r = 0.62; P < .05).

CONCLUSION

LUS identifies subtle congestion changes during the early postoperative period following KT. The hyperhydration strategy usually followed during this period does not result in overt pulmonary congestion as assessed by LUS, even in older recipients.

Plasma Volume and Renal Function Predict Six-Month Survival after Hospitalization for Acute Decompensated Heart Failure

Background

Plasma volume (PV) is contracted in stable patients with heart failure (HF) due to decongestion strategies. On the other hand, increased PV can adversely affect the trajectory of HF. We therefore examined the effects of increased percentage change in PV (%ΔPV), blood urea nitrogen (BUN), and %ΔPV stratified by BUN and glomerular filtration rate (GFR) on survival after discharge in patients hospitalized for acute decompensated HF (ADHF).

Methods

We used the Strauss-Davis-Rosenbaum formula to calculate the %ΔPV between baseline and hospital discharge in a cohort from the Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness trial (ESCAPE). Kaplan-Meier curves were constructed for survival over 6 months. Cox proportional hazards regression was used to obtain adjusted hazard ratios (HR) and 95% confidence intervals (95% CI) for the associations between survival after discharge and %ΔPV, BUN, and %ΔPV stratified by BUN and GFR.

Results

Of the 324 patients included in our study (age 56.1 ± 13.6 years, 26.5% female), those with increased or no %ΔPV at discharge were less likely to survive at 6 months compared with those having reduced %ΔPV (log rank, p = 0.0093). Increased %ΔPV (HR 1.08 per 10% increase; 95% CI: 1.02-1.14) and increased BUN at discharge (HR 1.02 per mg/dL; 95% CI: 1.01-1.03) were independently associated with worse survival. Decreasing %ΔPV had a greater association with improved survival in patients with discharge BUN <31 mg/dL (p = 0.02) and discharge GFR >40 mL/min/1.73 m² (p = 0.047).

Conclusions

Increased %ΔPV and BUN at discharge predicted worse 6-month survival in patients with ADHF. Decreased %ΔPV with low BUN or high GFR at discharge was associated with improved survival.