Changes in red blood cell volume during transition of heart failure status: a reflection of cellular hydration status?

Prognostic Significance of Serum Chloride Level Reduction in Patients with Chronic Heart Failure with Different Ejection Fractions

Little is known regarding the prognostic value of serum chloride in patients with chronic heart failure (CHF) with different ejection fractions. We sought to determine the postdischarge outcomes associated with lower serum chloride between different CHF types.We reviewed the medical records of 1221 consecutive patients with CHF admitted to the First Affiliated Hospital of Kunming Medical University from January 2017 to October 2021. After excluding patients with in-hospital death, missing follow-up data, missing serum chloride level data, or chronic dialysis therapy, 791 patients were included. Of these patients, 343 had heart failure with reduced ejection fraction (HFrEF; i.e., left ventricular ejection fraction (LVEF) < 40%), and 448 had heart failure with preserved ejection fraction (HFpEF) or heart failure with median ejection fraction (HFmrEF; HFpEF plus HFmrEF; i.e., LVEF ≥40%). Over a median follow-up of 750 days, 344 patients (43.5%) had all-cause mortality. In the univariate analysis, serum sodium and chloride were strongly associated with mortality in both HF subgroups (P < 0.0001). A multivariable model including both serum sodium and chloride showed the highly significant association between serum chloride and survival (P < 0.0001), whereas the association between serum sodium and mortality was not reported (HFpEF plus HFmrEF, hazard ratio (HR) 0.975, 95% confidence interval [CI] 0.942-1.010, P = 0.158; HFrEF, HR 1.007, 95% CI 0.966-1.051, P = 0.734). Kaplan-Meier survival curve analysis revealed a significant difference in mortality risk with decreasing chloride levels in all patients with CHF. The optimal cutoff value of chloride in predicting all-cause mortality was 102.95 mmol/L with area under the curve value of 0.76 [HR 0.760, 95% CI 0.727-0.793, P < 0.0001], sensitivity of 60.2%, and specificity of 78.3%.Lower serum chloride is an independent predictor of death in CHF, regardless of heart failure subtype.

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’.

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.

Effusion-Serum Chloride Gradient in Heart Failure-Associated Pleural Effusion - Pathophysiologic Implications

Background: There is scant clinical data of electrolyte analyses in the pleural fluid under heart failure (HF) pathophysiology.

Methods and Results: This study retrospectively analyzed data from 17 consecutive patients who presented with pleural effusion and underwent thoracentesis. A diagnosis of worsening HF was established by clinical criteria (presentation, echocardiography, serum B-type natriuretic peptide, and response to therapy). Samples of non-heparinized pleural fluid and peripheral venous blood, obtained within 2 h of each other, were subjected to biochemical analysis. The source of pleural effusion was determined as transudate or exudate according to Light’s criteria. Fifteen patients (53% men; mean [±SD] age 85±11 years) had HF-associated pleural effusion, 10 of whom had transudative effusion and 5 who had exudative effusion (fulfilling only 1 [n=4] or both [n=1] lactate dehydrogenase criteria). The effusion-serum gradient (calculated by subtracting the serum electrolyte concentration from the effusion electrolyte concentration) was significantly higher for chloride (mean [±SD] 7.4±2.6 mEq/L; range 4–14 mEq/L) than sodium (0.9±1.4 mEq/L; ranging from −1 to 4 mEq/L) and potassium (−0.1±0.3 mEq/L; ranging from −0.8 to 0.2 mEq/L; P<0.001 for each).

Conclusions: In HF-associated pleural effusion, the chloride concentration is higher in the pleural effusion than the serum, indicating that chloride may have an important role in the formation and retention of body fluid in the pleural space.

Dynamic changes in serum chloride concentrations during worsening of heart failure and its recovery following conventional diuretic therapy: A single-center study

BACKGROUND AND AIMS

Few data are available regarding the dynamic changes in the serum chloride concentrations in heart failure (HF) pathophysiology. The aim of the present study was to investigate changes in the serum chloride concentration under worsening HF and its recovery following conventional diuretic therapy.

METHODS

Blood test data, including measurements of serum albumin/solutes and b-type natriuretic peptide, at both worsening and recovery of HF status, were obtained from 47 patients with definite HF.

RESULTS

Ambulatory patients with HF were enrolled and followed up at the outpatient clinic of Nishida Hospital between June 2003 and March 2009. From clinically stable to worsening HF, the serum sodium concentration increased from (mean ± SD) 139 ± 4.1 to 141 ± 5.07 mEq/L (P < 0.05, two-way analysis of variance) and the serum chloride concentration increased from 101 ± 5.36 to 104 ± 5.44 mEq/L (P < 0.01) among all patients. After resolution of worsening HF by treatment with conventional diuretics, both the serum sodium concentration and serum chloride concentration decreased significantly to 138 ± 5.12 and 99.5 ± 5.33 mEq/L, respectively (P < 0.0001 for each). The absolute changes in the serum sodium concentration from clinically stable HF to worsening HF appeared to be lesser than those in the serum chloride concentration (1.70 ± 4.34 vs 2.72 ± 6.02 mEq/L, P = 0.079, t test), but this was not statistically significant. Absolute changes in the serum sodium concentration from worsening HF to its recovery following treatment with conventional diuretics were lesser than those in the serum chloride concentration (-2.87 ± 4.38 vs -4.45 ± 5.23 mEq/L, P = 0.0068, t test).

CONCLUSION

Under conventional diuretic therapy, greater changes occur in the serum chloride concentration than in the serum sodium concentration under HF state transitions, suggesting that chloride dynamics might contribute more to HF pathophysiology under such therapeutic circumstance.

Strategy for monitoring decompensated heart failure treated by an oral vasopressin antagonist with special reference to the role of serum chloride: A case report

Compared with conventional diuretic therapy, monitoring decompensated heart failure (HF) under treatment with a vasopressin antagonist is problematic because (1) use of this medication usually allows the patient free water intake to prevent drug-induced hypernatremia and (2) this medication often induces only minimal changes in the hemodynamics and blood concentration. In a 68-year-old female HF patient, use of tolvaptan did not induce much change in the urine output, presumably because of the low water intake due to a lack of thirst, but she did achieve a profound weight loss. Both the changes in chloride and sodium were negatively correlated with changes in the hemoglobin and serum creatinine, and positively correlated with changes in the mean red blood cell volume, but changes in the serum chloride were better correlated with each variable than were changes in the serum sodium. .