When to increase or reduce sodium loading in the management of fluid volume status during acute decompensated heart failure

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.

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.

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.

Proposal for heart failure progression based on the 'chloride theory': worsening heart failure with increased vs. non-increased serum chloride concentration

AIMS

Chloride (Cl) is an established key electrolyte for the activation of the renin-angiotensin-aldosterone system. Recent studies have shown the serum Cl as a key electrolyte for the regulation of body fluid distribution in heart failure (HF) patients. The clinical differences of worsening HF status according to the changes in serum Cl concentration are unclear.

METHODS AND RESULTS

Data from 47 chronic HF patients were analysed. Upon worsening HF, each patient exhibited at least two HF-related signs. Blood tests included haemoglobin (Hb), haematocrit (Ht), mean red blood cell volume (MCV), albumin, serum solutes, and b-type natriuretic peptide. The relative change in the plasma volume (%PV) from stable to worsening HF was estimated as follows: 100 × {Hb (stable) × [1 - Ht (worse)]}/{Hb (worse) × [1 - Ht (stable)]} - 100. When patients were divided into two groups based on changes in serum Cl concentration from stable to worsening HF, the pathophysiologic features of the patients with increased Cl (range 1-23 mEq/L; n = 31) included a greater increase in serum sodium (2.94 ± 4.15 vs. -0.69 ± 3.75 mEq/L, P = 0.005), higher vascular expansion (12 ± 11.1 vs. 4.81 ± 7.94%, P = 0.026), a tendency towards a greater MCV (1.23 ± 2.36 vs. -0.06 ± 1.88 fL, P = 0.065), and preserved renal function defined by the absence of an increase of serum creatinine (-0.24 ± 0.39 vs. -0.05 ± 0.12 mg/dL, P = 0.057) compared to patients with non-increased Cl (range -9 to 0 mEq/L; n = 16). Clinically, the increased Cl group had fewer HF signs (2.65 ± 0.71 vs. 3.31 ± 0.79, P = 0.005) although the change in symptoms did not differ between groups (48% vs. 63%, P = 0.54).

CONCLUSIONS

The present study suggests a new clinical entity of worsening HF status, that is, HF with increased vs. non-increased serum Cl concentration from clinical stability to worsening HF.

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

Body fluid volume regulation is a complex process involving the interaction of various afferent (sensory) and neurohumoral efferent (effector) mechanisms. Historically, most studies focused on the body fluid dynamics in heart failure (HF) status through control of the balance of sodium, potassium, and water in the body, and maintaining arterial circulatory integrity is central to a unifying hypothesis of body fluid regulation in HF pathophysiology. The pathophysiologic background of the biochemical determinants of vascular volume in HF status, however, has not been known. I recently demonstrated that changes in vascular and red blood cell volumes are independently associated with the serum chloride concentration, but not the serum sodium concentration, during worsening HF and its recovery. Based on these observations and the established central role of chloride in the renin-angiotensin-aldosterone system, I propose a unifying hypothesis of the "chloride theory" for HF pathophysiology, which states that changes in the serum chloride concentration are the primary determinant of changes in plasma volume and the renin-angiotensin-aldosterone system under worsening HF and therapeutic resolution of worsening HF.

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. .