The "chloride theory", a unifying hypothesis for renal handling and body fluid distribution in heart failure pathophysiology

The role of urine chloride in acute heart failure

In our retrospective study, we aimed to investigate the relationship between urinary chloride (uCl-) and selected clinical and laboratory biomarkers, renal function, and patient outcomes in the acute heart failure (AHF) population. We divided 248 adult patients (≥ 18 years) with AHF into two groups: low uCl- (< 115 mmol/L) and high uCl-. The mean age of the patient group was 70.2 ± 12.6, and 182 patients were male (73.4%). Clinical endpoints included in-hospital mortality, one-year mortality, and a composite endpoint of one-year mortality and rehospitalization for heart failure. Patients were followed up for at least one year. Relevant clinical and baseline biomarker data were collected, including markers concerning inflammation, liver and kidney function, perfusion and congestion, iron status, cardiac remodeling, gasometry, renin and aldosterone. Low uCl- was associated with worse in-hospital outcomes, including higher in-hospital mortality (7.7% vs. 1.4%, p = 0.014), the need for inotropic support (20.19% vs. 2.08%, p ≤ 0.001), worsening of HF during therapy (17.31% vs. 4.86%, p ≤ 0.001), and the need for treatment in an intensive cardiac care unit (33.65% vs. 15.28%, p ≤ 0.001). Low uCl- was a significant predictor of one-year mortality (40.4% vs. 16.7%, p < 0.05) and the composite outcome (HR 2.42, 95% CI 1.43-4.08, p < 0.001). In the multivariable analysis, uCl- was independently associated with the risk of one-year mortality (HR 0.92, 95% CI 0.87-0.98, p < 0.05) and the composite outcome (HR 0.95, 95% CI 0.92-0.99, p < 0.05). Our findings suggest that low uCl- is a marker of more advanced heart failure, activation of the renin-angiotensin-aldosterone system and is related to worse one-year outcomes.

Hypertonic saline and heart failure: "sodium-centric" or "chlorine-centric"?

Up to 50% of patients admitted for heart failure (HF) have congestion at discharge despite diagnostic and therapeutic advances. Both persistent congestion and diuretic resistance are associated with worse prognosis. The combination of hypertonic saline and loop diuretic has shown promising results in different studies. However, it has not yet achieved a standardized use, partly because of the great heterogeneity in the concentration of sodium chloride, the dose of diuretic or the amount of sodium in the diet. Classically, the movement of water from the intracellular space due to an increase in extracellular osmolarity has been postulated as the main mechanism involved. However, chloride deficit is postulated as the main up-regulator of plasma volume changes, and its correction may be the main mechanism involved. This "chloride centric" approach to heart failure opens the door to therapeutic strategies that would include diuretics to correct hypochloremia, as well as sodium free chloride supplementation.

The association between serum chloride and mortality in ICU patients with heart failure: The impact of bicarbonate

OBJECTIVE

To assess whether serum chloride predicts risk of death in intensive care unit (ICU) patients with heart failure (HF) and the effect of bicarbonate on the efficacy of serum chloride in predicting risk of death in ICU patients.

METHODS

A total of 9364 HF patients hospitalized in the ICU were enrolled. Patients were divided into hypochloremia (< 96 mEq/L), normal chloride (96-108 mEq/L), and hyperchloremia (> 108 mEq/L) groups. Similarly, we divided the serum bicarbonate level into three groups: low bicarbonate (< 22 mEq/L), medium bicarbonate (22-26 mEq/L), and high bicarbonate (> 26 mEq/L). The outcome of this study was in-hospital mortality. Then, we analyzed the association between abnormal serum chloride and mortality according to the category of serum bicarbonate and assessed the interaction effect. Restricted cubic spline (RCS) was used to show possible nonlinear associations.

RESULTS

In the overall study population, hypochloremia was associated with a higher risk of in-hospital mortality than normal chloride (odds ratio [OR] 1.54, 95% confidence interval [CI] 1.26-1.86, P < 0.001), hyperchloremia was not significantly related to in-hospital mortality (OR 1.00, 95% CI 0.85-1.19, P = 0.962). However, a linear association between serum chloride and in-hospital mortality was found in the low and normal bicarbonate groups (all P for nonlinear >0.05).

CONCLUSIONS

Hypochloremia is associated with in-hospital mortality and longer hospital stay in critically ill patients with HF. In addition, risk of death in the low and medium serum bicarbonate groups decreased with increasing serum chloride level.

[Pulmonary heart: A review]

The review on the problem of the pulmonary heart pursues two goals: firstly, to restore historical justice and to show the priority studies of doctor Dmitry D. Pletnev on such problems as diagnosis of right ventricular myocardial infarction, clinical characteristics of congestive heart failure of the right ventricle; secondly, to outline the modern concept of the pulmonary heart. The review provides an analysis of the pathogenetic mechanisms of the development of heart failure in the pulmonary heart. Much attention is paid to echo cardiography data and biological markers are emphasized in assessing the function of the right atrium, right ventricle, tricuspid valve regurgitation, pulmonary artery pressure. Prognostically unfavorable signs of the course of the pulmonary heart have been identified, which include a high degree of tricuspid valve regurgitation, the amplitude of movement of the fibrous valve ring (TAPSE) and atrial fibrillation developing with dilation of the right atrium.

Prognostic impact of serum chloride concentrations in acute heart failure patients: A systematic Rreview and meta-analysis

OBJECTIVE

Acute heart failure (AHF) is a common disease in the emergency departments. Its occurrence is often accompanied by electrolyte disorders, but little attention is paid to chloride ion. Recent studies have shown that hypochloremia was associated with poor prognosis of AHF. Therefore, this meta-analysis aimed to assess the incidence of hypochloremia and the impact of the reduction of serum chloride on the prognosis of AHF patients.

METHODS

We searched Cochrane Library, Web of science, PubMed, Embase databases and searched the relevant studies on chloride ion and AHF prognosis. The search time is from the establishment of the database to December 29, 2021. Two researchers screened the literature and extracted data independently. The quality of the included literature was evaluated using Newcastle-Ottawa Scale (NOS) scale. The effect amount is expressed as hazard ratio (HR) or relative risk (RR) and 95% confidence interval (CI). Review Manager 5.4.1 software for was used to perform the meta-analysis.

RESULTS

Seven studies involving 6787 AHF patients were included in meta-analysis. Meta-analysis revealed that the incidence of hypochloremia in AHF patients at admission was 17% (95% CI: 0.11-0.22); One mmol /L decrease in serum chloride at admission was associated with 6% increased risk of all-cause death of AHF patients (HR = 1.06, 95% CI: 1.04-1.08, P < 0.00001); Compared with the non-hypochloremia group, the risk of all-cause death in the hypochloremia group increased by 1.71 times (RR = 1.71, 95% CI: 1.45-2.02, P < 0.00001), the risk of all-cause death in the progressive hypochloremia(development of hypochloremia after admission) group increased by 2.24 times (HR = 2.24, 95% CI: 1.72-2.92, P < 0.00001), and the risk of all-cause death in the persistent hypochloremia (hypochloremia both on admission and at discharge) group increased by 2.80 times (HR = 2.80, 95% CI: 2.10-3.72, P < 0.00001).

CONCLUSION

The available evidence shows that the decrease of chloride ion at admission is associated with poor prognosis of AHF patients, and the prognosis of persistent hypochloremia is worse.Some outcome indicators(progressive hypochloremia, persistent hypochloremia, and composite of death + HF hospitalization)are as few as 2 studies in the literature, and the results should be interpreted carefully.

Relationship between serum chloride and prognosis in non-ischaemic dilated cardiomyopathy: a large retrospective cohort study

OBJECTIVES

Serum chloride has a unique homeostatic role in modulating neurohormonal pathways. Some studies have reported that hypochloremia has potential prognostic value in cardiovascular diseases; thus, we aimed to investigate the association of baseline serum chloride with clinical outcomes in elderly patients with non-ischaemic dilated cardiomyopathy (NIDCM).

DESIGN

Retrospective study.

SETTING AND PARTICIPANT

A total of 1088 patients (age ≥60 years) diagnosed with NIDCM were enrolled from January 2010 to December 2019.

RESULTS

Logistic regression analyses showed that serum chloride was significantly associated with in-hospital death. Receiver operating characteristic (ROC) curve analyses showed that serum chloride had excellent prognostic ability for in-hospital and long-term death (area under the curve (AUC)=0.690 and AUC=0.710, respectively). Kaplan-Meier survival analysis showed that the patients with hypochloremia had worse prognoses than those without hypochloremia (log-rank χ²=56.69, p<0.001). After adjusting for age, serum calcium, serum sodium, left ventricular ejection fraction, lg NT-proBNP and use of diuretics, serum chloride remained an independent predictor of long-term death (HR 0.934, 95% CI 0.913 to 0.954, p<0.001).

CONCLUSIONS

Serum chloride concentration was a prognostic indicator in elderly patients with NIDCM, and hypochloremia was significantly associated with both in-hospital and long-term poor outcomes.

Mechanistic insights into chloride-related heart failure progression according to the plasma volume status

Aims

Two types of heart failure (HF) progression were recently proposed on the basis of an increased vs. non‐increased serum chloride concentration. The applicability of this concept to real‐world HF pathophysiology requires further investigation. The present study evaluated the mechanisms of HF progression to a different type according to changes in the estimated plasma volume status (ePVS).

Methods and results

Data from 47 patients (32% men; 78.2 ± 9.7 years of age) with stable to worsening HF (37.5 ± 16 days) were analysed. Physical examination, standard blood tests, and b‐type natriuretic peptide (BNP) measurements were conducted. The ePVS was calculated as follows: ePVS (dL/g) = [100 − haematocrit (%)]/[haemoglobin (g/dL)]. For the study subjects as a whole (n = 47), changes in the ePVS correlated positively with changes in the serum chloride concentration from stable to worsening HF (r = 0.398, P = 0.0056). When divided into two groups of worsening HF with an increased (n = 31) vs. non‐increased serum chloride concentration (n = 16), no significant baseline differences in body weight, serum logBNP, or ePVS were detected between groups. Under worsening HF, the increase in body weight (2.34 ± 1.12 vs. 2.59 ± 1.56 kg, P = 0.57) and logBNP (0.39 ± 0.30 vs. 0.54 ± 0.31 pg/mL, P = 0.13) did not differ between groups, but the increase in the ePVS was smaller in the group with a non‐increased serum chloride concentration compared with that with an increased serum chloride concentration (0.292 ± 0.49 vs. 0.653 ± 0.60 dL/g, P = 0.044). An increase in the %change in ePVS ≥ 10% was less common in patients with a non‐increased chloride concentration (37% vs. 71%, P = 0.03). Patients with a non‐increased serum chloride concentration had more HF signs (3.31 ± 0.79 vs. 2.65 ± 0.71, P = 0.005) and a higher incidence of pulmonary rales (63% vs. 16%, P = 0.0024) than those with an increased serum chloride concentration.

Conclusions

According to the changes in the ePVS, HF progression may result from a difference between two HF types (i.e. increased vs. non‐increased serum chloride concentration) in the cardiac reserve in response to a given cardiac burden by modulating plasma volume status via the possible tonicity potential of chloride.

Chloride in Heart Failure: The Neglected Electrolyte

The increasing burden of heart failure (HF) and emerging knowledge regarding chloride as a prognostic marker in HF have increased the interest in the pathophysiology and interactions of chloride abnormalities with HF-related factors and treatments. Chloride is among the major electrolytes that play a unique role in fluid homeostasis and is associated with cardiorenal and neurohormonal systems. This review elucidates the role of chloride in the pathophysiology of HF, evaluates the effects of treatment on chloride (eg, diuretic agents cause higher urinary chloride excretion and consequently serum hypochloremia), and discusses recent evidence for the association between chloride levels and mortality.

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.

Enhancement of the serum chloride concentration by administration of sodium-glucose cotransporter-2 inhibitor and its mechanisms and clinical significance in type 2 diabetic patients: a pilot study

BACKGROUND

Chloride is a key electrolyte that regulates the body fluid distribution. Accordingly, manipulating chloride kinetics by selecting a suitable diuretic could be an attractive strategy for correcting body fluid dysregulation. Therefore, this study examined the effects and contributing factors of a sodium-glucose cotransporter-2 inhibitor (SGLT2i) on the serum chloride concentration in type 2 diabetic (T2DM) patients without heart failure (HF).

METHODS

This study was a retrospective single-center observational study that enrolled 10 T2DM/non-HF outpatients for whom the SGLT2i empagliflozin (daily oral dose of 10 mg) was prescribed. Among these 10 patients, 6 underwent detailed clinical testing that included hormonal and metabolic blood tests.

RESULTS

Empagliflozin treatment for 1-2 months decreased body weight (- 2.69 ± 1.9 kg; p = 0.002) and HbA1c (- 0.88 ± 0.55%; p = 0.0007). The hemoglobin (+ 0.27 ± 0.36 g/dL; p = 0.04) and hematocrit (+ 1.34 ± 1.38%; p = 0.014) values increased, but the serum creatinine concentration remained unchanged. The serum chloride concentration increased from 104 ± 3.23 to 106 ± 2.80 mEq/L (p = 0.004), but the sodium and potassium concentrations did not change. The spot urinary sodium concentration decreased from 159 ± 43 to 98 ± 35 mEq/L (p < 0.02) and the spot urinary chloride tended to decrease (from 162 ± 59 to 104 ± 36 mEq/L, p < 0.08). Both renin and aldosterone tended to be activated (5/6, 83%). The strong organic acid metabolite concentrations of serum acetoacetate (from 42 ± 25 to 100 ± 45 μmol/L, p < 0.02) and total ketone bodies (from 112 ± 64 to 300 ± 177 μmol/L, p < 0.04) increased, but the actual HCO3 - concentration decreased (from 27 ± 2.5 to 24 ± 1.6 mEq/L, p < 0.008).

CONCLUSIONS

The present study demonstrated that SGLT2i enhances the serum chloride concentration in T2DM patients and suggests that the effect is mediated by the possible following mechanisms: (1) enhanced reabsorption of urinary chloride by aldosterone activation due to blood pressure lowering and blood vessel contraction effects, (2) reciprocal increase in the serum chloride concentration by reducing the serum HCO3 - concentration via a buffering effect of strong organic acid metabolites, and (3) reduced NaHCO3 reabsorption and concurrently enhanced chloride reabsorption in the urinary tubules by inhibiting Na+-H+ exchanger 3 in the renal proximal tubules. Thus, the diuretic SGLT2i induces excessive extravascular fluid to drain into the vascular space by the enhanced vascular "tonicity" caused by the elevated serum chloride concentration.

Comparison of Changes in Plasma Volume and Renal Function between Acetazolamide and Conventional Diuretics: Understanding the Mechanical Differences according to the "Chloride Theory"

OBJECTIVE

We compared the effects of the chloride-regaining diuretic acetazolamide with those of conventional diuretics on plasma volume, serum electrolytes, and renal function in acutely decompensated heart failure (HF) patients.

METHODS

A retrospective analysis was performed on the data of 13 patients treated with acetazolamide (Group A) and 13 patients with conventional diuretics (Group B) matched based on diuresis-induced weight reduction (≥1 kg) during resolution of worsening HF. Changes in plasma volume (Strauss formula), renal function, and serum electrolytes under treatment were determined by peripheral blood tests.

RESULTS

Clinical characteristics at baseline were not different between groups A and B. After diuretic therapy, body weight reduction (-2.23 ± 1.11 vs. -2.22 ± 1.06 kg, p = 0.97) and the number of residual HF-related signs (0.31 ± 0.48 vs. 0.23 ± 0.44, p = 0.67) was not different between groups. After each treatment, the serum chloride concen-tration increased in Group A, but decreased in Group B (+5.31 ± 4.91 vs. - 4.54 ± 4.68 mEq/L, p < 0.0001). Plasma volume (0.63 ± 13.1 vs. -12.1 ± 10.5%, p < 0.01) and renal function determined by changes in serum creatinine concentration (0.048 ± 0.12 vs. 0.21 ± 0.24 mg/dL, p < 0.047) were preserved in Group A compared with Group B.

CONCLUSIONS

While both groups exhibited equivalent body weight reduction and resolution of HF-related signs after each diuretic treatment, acetazolamide treatment preserved plasma volume and renal function compared to conventional diuretics.

Effects of exercise on cations/anions in blood serum of English Thoroughbred horses

ABSTRACT English Thoroughbred horses, are widespread in Mexico and due to the lack of data on their exercise physiology, it is important to conduct exercise tests in order to obtain information the effects of exercise on more essential cations/anions in blood serum, as these horses are submitted to constant efforts. The study was carried out with 150 blood samples of English Thoroughbred horses clinically healthy. The blood sample collection was performed during three periods: 1) rest, 2) 30min after exercise (speed race of 12km/h for 30min with no rest) and 3) 60min after exercise. Mean values were calculated for cations (sodium and potassium) and anions (chloride and bicarbonate). The resulting data set was analyzed using Gaussian distribution and descriptive statistics. Confidence intervals of 95% were established. The linear relationships between ions were quantified, and an analysis of variance was performed to compare the mean values between groups. The concentrations of the described analytes are consistent with values reported by international literature. The comparison between groups, revealed that during exercise, sodium ion did not show changes 30min after exercise and increase 60min after. Potassium ion showed increase 30min after exercise and decrease 60min after. Chloride ion showed a decrease 30min after exercise, to recover gradually 60min after. Meanwhile, bicarbonate ion showed increase 30min after exercise, decreasing slightly in the final stage. Negative correlation between bicarbonate ion and chloride ion were determined. It was concluded that exercise tests are useful for the determination of acid-base balance and osmotic balance, and their main role is to evaluate the athletic ability of horses.Considering that chloride ion excretion and metabolic adjustments of potassium ion and bicarbonate ion are superior to water loss, compared to the normal osmolarity of blood serum. The results found can be used to structure an adequate replacement program of electrolytes lost in sweat.

Acetazolamide as a potent chloride-regaining diuretic: short- and long-term effects, and its pharmacologic role under the 'chloride theory' for heart failure pathophysiology

According to the "chloride theory" for heart failure (HF) pathophysiology, manipulation of the serum chloride concentration is an important therapeutic target. This study determined the short- and long-term effects of acetazolamide (Diamox), a potential chloride-regaining diuretic, on peripheral blood, serum electrolytes, and renal function. Effects of low-dose Diamox (250-500 mg/day) were evaluated in 30 HF patients for whom Diamox was added as de-novo/add-on decongestion therapy for acutely worsening HF (n = 18) or as modification therapy for serum hypochloremia in stable HF ( < 100 mEq/L; n = 12). Peripheral hematologic tests were performed at baseline, and at short- ( ≤ 10 days) and long-term ( ~ 60 days) time-points. In all 30 study patients of both groups, the serum chloride concentration increased in the short-term and even further over the long-term. The serum potassium concentration constantly decreased throughout the study period. Both the blood urea nitrogen and serum creatinine concentrations increased in the short-term, but returned to baseline levels over the long-term. Responders to Diamox (n = 13; defined by HF resolution and body weight loss ≥ 1 kg) in the decongestion group exhibited reduced serum b-type natriuretic peptide levels and a markedly increased serum chloride concentration, but the hemoglobin/hematocrit and serum creatinine concentrations did not change after treatment. In conclusion, acetazolamide is a potent candidate "chloride-regaining diuretic" for treating HF patients under the "chloride theory". Its effect to enhance the serum chloride concentration occurred within 10 days and persisted for at least ~ 60 days. Plasma volume and renal function were preserved under adequate diuretic treatment with acetazolamide.

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.

Vasopressin antagonist-like effect of acetazolamide in a heart failure patient: a case report

Background

Hyponatraemia is easily corrected by treatment with an oral vasopressin antagonist, but these medications are costly and their use at outpatient clinics is restricted by government-managed insurance in Japan. Acetazolamide could be an alternative diuretic to a vasopressin antagonist.

Case Summary

An 83-year-old dyspnoeic male patient was emergently admitted to the hospital due to decompensated heart failure (HF), hypotension, and hyperkalaemia-associated sinus arrest with a junctional escape rhythm. Urgent treatment with a noradrenaline drip infusion and a beta stimulant adhesive skin patch promptly restored sinus rhythm with conducted normal QRS complex, which resolved the hypotension. Blood tests on admission revealed moderately elevated b-type natriuretic peptide (BNP, 576 pg/mL), hyponatraemia (128 mEq/L), hypochloraemia (95 mEq/L), hyperkalaemia (5.7 mEq/L), and preserved renal function (creatinine, 1.0 mg/dL) under no cardiovascular medications. Immediately after admission, low-dose oral acetazolamide (500 mg/day) and polystyrene sulfonate-Ca jelly (Argamate, 25 g/day for 3 days) were prescribed to correct the decompensated HF status and electrolyte disturbance. Three days later, both the serum sodium and chloride concentrations had recovered to normal levels (136 mEq/L and 104 mEq/L, respectively), and the serum potassium concentration had decreased to 4.5 mEq/L. Two weeks later, the patient’s HF status became stable and the serum BNP concentration returned to normal (55 pg/mL).

Discussion

The present case indicates that the classic diuretic of acetazolamide would have a vasopressin blockade-like effect and could be an alternative diuretic to vasopressin antagonists for some proportion of HF patients with hyponatraemia.

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

This study examined how changes in heart failure (HF) status induce changes in the index of erythrocyte hydration based on mean red blood cell volume (MCV). Data from 47 HF patients (32% men; 78.2 ± 9.7 years) that experienced worsening and recovery of HF were analysed. Blood tests included measurements of MCV, albumin, serum solutes and b-type natriuretic peptide (BNP). Among a total of 47 worsening HF events, changes in MCV were positively correlated with changes in body weight (r = 0.31, p = .034), serum sodium (r = 0.417, p = .0036), and chloride (r = 0.457, p = .0012), and negatively correlated with changes in blood urea nitrogen (r= -0.389, p = .0069) and creatinine (r= -0.494, p = .0004). At recovery from worsening of HF by conventional diuretic therapy, change in MCV was positively correlated with the change in body weight (r = 0.457, p = .0012), serum sodium (r = 0.466, p = .001) and chloride (r = 0.484, p = .0006). Multivariate regression analysis demonstrated an independent association between the increase in serum chloride and MCV from stability to worsening of HF (odds ratio [OR] 6.02, 95% confidence interval [CI] 1.09-33.2, p = .039) and the increase or absence of change in serum chloride concentration and preserved MCV after decongestion (OR 11.5, 95% CI 1.53-85.9, p = .017). In conclusion, this study demonstrates that the changes in MCV under transition in HF status do not reflect a change that occurs in parallel with changes in HF-related markers, such as body weight and serum BNP level, but is independently associated with a change in the serum chloride concentration. Whether changes in MCV actually reflect the bodily cellular hydration status warrants further research.

Treatment of hypochloremia with acetazolamide in an advanced heart failure patient and importance of monitoring urinary electrolytes

Chloride was recently recognized to play an important role in the pathophysiology of heart failure (HF). Chloride manipulation, including the use of acetazolamide, may be a requisite therapeutic target in HF treatment. An 87-year-old male patient with advanced HF and hypertrophic cardiomyopathy was admitted to the hospital due to hypochloremia (94 mEq/L) and hyponatremia (134 mEq/L) under diuretic treatment with azosemide, spironolactone, and tolvaptan. On admission, HF-related signs of overhydration were lacking, but B-type natriuretic peptide was moderately elevated. The etiology of the hypochloremia/natremia state was depletion of both electrolytes based on serum analysis and spot urinary concentrations. Immediately after admission, acetazolamide (500 mg/d) was prescribed to correct the hypochloremia in parallel with cessation of the preceding administration of azosemide and spironolactone, and tapering off of the tolvaptan over 7 days. Under treatment, both serum chloride and sodium concentrations recovered to normal (108 mEq/L and 148 mEq/L, respectively), and the serum potassium concentration decreased from 3.9 mEq/L to 2.4 mEq/L. Urinary concentrations of sodium and potassium increased from 18 mEq/L to 31 mEq/L and from 19 mEq/L to 51.5 mEq/L respectively, in concordance with the changes in serum concentrations, but the chloride concentration decreased from 18 mEq/L to 12 mEq/L, opposite the changes in the serum concentration. <Learning objective: The present case confirms that the classic drug acetazolamide, although rarely used now for HF treatment, is a potent "chloride-regaining" or "chloride-retaining diuretic" with concomitant activity to reduce serum potassium. Additionally, this case study highlights the importance of monitoring both serum and urinary electrolyte concentrations to determine the electrolyte disturbance and efficacy of diuretic treatment through analytic evaluation of changes in the serum electrolytes and their tubular reabsorption in the kidney.>.