Peritoneal dialysis in patients with refractory congestive heart failure

Abstract

Chronic heart failure is a growing problem. Despite progress in its management, many patients become refractory to therapies including diuretic resistance, major congestion, and worsening renal function. The only alternative to get rid of excess water and sodium is ultrafiltration, which can be achieved via hemodialysis or peritoneal dialysis (PD). The majority of studies have shown multiple benefits of PD as an improvement in functional class, a reduction in hospitalization leading to increased quality of life, and even a reduction in mortality. Being a home dialysis technique, it is more favorably accepted by patients. It remains necessary to confirm these potential positive outcomes and to identify patients who would benefit the most from this treatment in the era of new therapies available to date.

INTRODUCTION

The increase in the incidence of heart failure makes it a public health problem. In fact, the number of cases has doubled over the past thirty years. This increase, estimated at 5% per year, is explained by the presence of numerous cardiovascular risk factors, unhealthy lifestyles, and difficulties in terms of access to optimal medical treatment. The increase in life expectancy linked to medical progress also explains the increase in the prevalence of heart failure in the elderly population. Patients with advanced heart failure who can be considered refractory are estimated to be 1%–10% of all patients with heart failure who could be offered mechanical circulatory therapy and/or cardiac transplantation. However, only a small proportion of selected patients could benefit from these therapeutic options; a large number of patients cannot access these treatments because of age and comorbidities, thus being directed to palliative care.

Refractory heart failure may be retained in patients with NYHA stage III or IV dyspnea and who are unresponsive to maximal drug treatment with high doses of loop diuretics combined with thiazide diuretics and/or spironolactone, renin-angiotensin-aldosterone system inhibitors, beta-blockers, and water and salt restriction. The life expectancy of these patients is very limited, not exceeding one year, and it is burdened with high morbidity linked to numerous episodes of congestion leading to frequent and prolonged hospitalizations.

Water and sodium overload is a common problem of most patients with refractory heart failure and represents the first cause of hospitalization. It also contributes to the progression of heart failure. Renal dysfunction and resistance to diuretics are often associated with fluid overload, making congestion difficult to control, thus worsening the prognosis[1];[2]. At this level, the therapeutic options remain rare and limited. Among them, peritoneal dialysis (PD) was first used in 1949 and has been gaining interest gradually over the past twenty years. Different clinical cases, small series, and often retrospective studies have reported favorable outcomes with PD in patients with different types of cardiomyopathy responsible for congestive heart failure with preserved or reduced ejection fraction[3]. Data from the French-language Peritoneal Dialysis Registry (RDPLF) shows a marked increase in the use of PD for cardio-renal syndrome over the past ten years. Indeed, between 2010 and 2021, the percentage of patients treated by PD for cardio-renal syndrome was multiplied by 3.5, going from 2.2% to 7.7%. In this population, cardio-renal syndromes are clearly more observed in men in 74.2% of cases than in women (25.8%), while the other nephropathies responsible for chronic renal failure treated by PD are mainly reported in women in 62% of cases (men in 38%). The average age of these patients is 75.2 ± 9.8 years, while the average age of the other patients treated by PD is 66 ± 17 years. Thus, based on this data, we propose a review of the literature on the place of PD in the treatment of congestive heart failure.

I. RENAL DYSFUNCTION AND RESISTANCE TO DIURETICS IN HEART FAILURE

The pathophysiology of kidney failure associated with heart failure has two main mechanisms. For many years, decreased cardiac output and fluid redistribution in heart failure were considered the primary causes of renal dysfunction through decreased renal perfusion, the activation of the sympathetic nervous system, and renin/angiotensin/aldosterone, thus causing water and sodium retention to preserve renal function and the glomerular filtration rate. In the long term, these mechanisms induce harmful effects on the heart and kidneys by activating the mechanisms of fibrosis, apoptosis, oxidative stress, and inflammation (Figure 1).

Figure 1.Bidirectional axis linking heart failure, renal dysfunction and congestion in cardiorenal syndrome

In recent years, it has been proposed that the increased pressure in the renal veins caused by fluid overload is the cause of renal dysfunction in this situation[4]. This increase in pressure reduces the net gradient at the level of the glomerular filtration mechanism, thus causing a decrease in the rate of glomerular filtration and thus reducing the elimination of water and sodium, aggravating renal congestion[5]. This congestion is the first cause of the poor prognosis in these patients and is considered to have a significantly greater impact than other risk factors such as renal failure. It has thus been demonstrated that patients without congestion had a better prognosis regardless of the presence or absence of renal insufficiency. In contrast, the risk of mortality and readmission is increased in patients with persistent chronic congestion alone or associated with impaired renal function. Patients receiving high-dose decongestant therapy during an episode of cardiac decompensation had a lower six-month mortality rate even though this therapeutic strategy was associated with impaired renal function[6]. Thus, congestion control is associated with a better prognosis, hence reducing the rate of hospitalization and preventing the worsening of renal function secondary to fluid overload[7].

Loop diuretics are the mainstay of treatment for congestive heart failure. High doses are well tolerated and allowed in most cases to promote the clinical improvement of the patient as well as fully prevent water and sodium retention. Failure to achieve decongestion despite increasing the diuretic dose is defined as a state of diuretic resistance, with a prevalence ranging from 21% to 35%, and this diuretic resistance is independently associated with mortality risk[8].

Many mechanisms have been implicated in the development of diuretic resistance. Variations in pharmacodynamics and pharmacokinetics through changes in the absorption, distribution,

.....