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CORRESPONDENCE |
Division of Nephrology Miulli General Hospital Acquaviva delle Fonti, Italy
* e-mail: basile.miulli{at}libero.it
Editor:
Congestive heart failure (CHF), the end stage of many cardiac diseases, is a complex clinical syndrome characterized by the heart's inability to guarantee sufficient blood flow in order to satisfy the metabolic requirements of the organism. The estimated prevalence of CHF increases with ageing of the population and affects 1% of adults and 5% of people aged >65 years (1). Approximately 25% of patients hospitalized because of refractory CHF have chronic renal failure and most have arterial hypertension, diabetes mellitus, and coronary artery disease (2). It is estimated that 50% of patients affected by NYHA class IV CHF die (3,4).
The most important therapeutic aim in the treatment of CHF is resolution of the edematous state. Despite salt and water restriction and the use of aggressive drugs, such as diuretics, digitalis, angiotensin-converting enzyme (ACE) inhibitors, beta-blockers, and angiotensin receptor antagonists, resistance and refractoriness to therapy are often encountered. Therefore, in order to maintain the patient alive, it becomes necessary to replace kidney function with alternative treatments, such as peritoneal dialysis (PD), isolated ultrafiltration (UF), or continuous hemofiltration, with the objectives of correcting the hemodynamic state, reducing the symptoms of CHF, and returning to the previous renal function (guidelines of the American College of Cardiology and the American Heart Association) (5).
Here we describe our experience with long-term treatment of refractory CHF by means of PD with 7.5% icodextrin solutions (ICO; Extraneal; Baxter Healthcare SA, Castlebar, Ireland). We report 4 patients [all males; mean age 71.5 ± 5.6 (SD) years, range 64 – 77 years] with NYHA class IV CHF refractory to intensive drug therapy and with varying degrees of chronic renal failure predating the CHF. The causes of chronic renal failure were nephroangiosclerosis in 1 patient and diabetic nephropathy in the 3 other patients. The etiology of cardiac disease was secondary to pathology of the cardiac valves in 2 patients and secondary to ischemic and/or hypertensive cardiopathy in the 2 other patients (Table 1). All patients had a poor quality of life because of CHF symptoms (dyspnea, edema, asthenia) and frequent hospitalizations due to cardiac illnesses. Patients had received therapy with diuretics (4 patients), ACE inhibitors (4 patients), and digitalis (2 patients) and were followed with periodic cardiologic consultations, including electro- and echocardiograms to estimate the ejection fraction (EF). All patients had been in danger of imminent death due to water overload and refractoriness to conventional intensive treatment (furosemide 500 – 750 mg intravenously, spironolactone 50 – 100 mg orally, ACE-inhibitors, and digoxin). Three patients showed anasarca and acute renal failure requiring rescue extracorporeal UF and some hemodialysis sessions before implanting the peritoneal catheter and starting PD (5 sessions in Patient 1; 7 in Patient 3; 14 in Patient 4). The last patient (Patient 2) started with PD.
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In order to maintain plasma volumes within acceptable limits for patients with refractory CHF, all patients were enrolled in a long-term program of intermittent PD: 1 nocturnal exchange with ICO in 3 patients and 2 exchanges in 1 patient (ICO + 1.36% isotonic dextrose solution) (Table 1). All patients were advised to be on a low sodium diet, to take daily blood pressure measurements, and to record PD UF and body weight. Renal function, daily diuresis, body weight, peritoneal UF, mean arterial pressure (defined as diastolic pressure + 1/3 the difference between systolic and diastolic pressure), changes in NYHA class, EF, and peritonitis episodes were monitored before and during PD treatment (at 0, 3, 6, 12, 18, 24, 30, 36, and 43 months). The average of the last three measurements of the follow-up was reported for each patient. Hospitalization days due to cardiac illnesses occurring during the 12 months preceding the start of PD and during the PD follow-up period were also recorded.
Statistical analysis was performed using Student's paired t-test, with statistical significance being set at p < 0.05.
Mean follow-up was 24.3 ± 15.6 months. After being stabilized on PD, all patients had a statistically significant increase in daily diuresis (from 587.5 ± 165.2 to 1700.0 ± 141.4 mL, p < 0.003) (Table 2) and a statistically nonsignificant decrease in serum creatinine level (from 3.55 ± 1.12 to 2.37 ± 0.35 mg/dL) (Table 2). Decrease in body weight was statistically significant (11.3 ± 3.4 kg, p < 0.007) (Table 2). All patients showed a statistically significant improvement in NYHA class (from 4.0 ± 0.0 to 2.5 ± 2.6, p < 0.01) (Table 2). Mean arterial pressure increased and became stable during the follow-up period (Table 2). Ejection fraction, as measured by echocardiography, increased in 1 patient, remained stable in 2 patients, and worsened in 1 patient (EF before the start of PD 45% ± 27.7%; EF after the start of PD 59.0% ± 23.1%).
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Hospitalization days due to cardiac illnesses decreased: 3 patients had no hospitalizations due to cardiac illnesses during the PD follow-up period; the fourth patient was hospitalized for 209 days in a cardiology ward during the year preceding the start of PD and for 41 days during the follow-up period. Normalizing these data as hospitalization days per month, there was a decrease from 4.4 ± 2.9 to 0.7 ± 1.5 days during the 12 months preceding the PD and during the PD follow-up period respectively (p < 0.04) (Table 2). No episode of peritonitis occurred during the follow-up period (Table 1). Three of the 4 patients died (at 43, 11, and 13 months) after beginning PD treatment (Table 1): 2 died suddenly and 1 died of neoplastic cachexia. No death could be attributed to any complication related to PD treatment.
With more than 100 patients reported in the literature, experience with PD as a chronic treatment for refractory CHF is larger compared with the acute situation (6). Although all the evidence available has to be derived from case series, the large majority of patients treated with PD and reported in the literature experienced an improvement in functional status (6). Despite clinical improvement, median survival of patients treated with PD in the available reports appears to be <1 – 2 years. Therefore, a beneficial effect of PD on outcome in these patients remains to be shown (6).
Our results show that PD (1 exchange/day with ICO or 2 exchanges/day with ICO + 1.36% isotonic dextrose solution) allows maintenance of a satisfactory water balance and stable body weight while preserving residual renal function and responsiveness to conventional therapy. Peritoneal dialysis can correct electrolyte and water imbalance for short and long periods of time and can improve cardiac function and NYHA class, especially in patients affected by mild or moderate chronic renal failure. The latter occurs often in CHF patients and its prevalence increases with the seriousness of the illness (60% – 70% in patients of NYHA III and IV classes) (7).
Our choice among PD solutions is icodextrin, a glucose polymer that is absorbed only after having undergone intraperitoneal hydrolysis (ultimately to maltose) (8). It has a lower content of glucose degradation products than conventional PD fluids. Furthermore, it has an UF capacity broadly similar to 2.27% glucose-containing solutions but, owing to a reduced back diffusion from the intraperitoneal cavity into the circulation, it allows longer sustained UF, which is particularly suited to long dwells (8). The use of one daily peritoneal exchange reduces the risk of peritonitis from touch contamination and the possibility of complications related to PD per se. These aspects make ICO an attractive home PD option for treating refractory CHF. We are aware of only one report about the use of ICO solutions in the long-term treatment of refractory CHF (9).
In agreement with other studies (10), our data showed no correlation between functional improvement and improvement in ventricular EF, as measured by echocardiography. All patients in our study had an improvement in their NYHA class (1 or 2 classes) and reduced hospitalization days. Even though patients affected by refractory CHF represent only 13% of all patients with CHF, they are responsible for about 50% of hospitalization costs due to CHF, with an annual average of 4 hospitalizations per year, often in intensive care units (4).
In conclusion, based on both published literature and our own results, we propose PD with ICO solutions as a valuable long-term treatment of refractory CHF in patients with mild or moderate chronic renal failure. The goal of this treatment is to manage plasma volumes, allowing improvement in the quality, if not in the quantity, of life during the end stage of this chronic disease. Furthermore, hospitalizations due to cardiac illnesses are strikingly reduced. Randomized controlled trials are needed to confirm the evidence derived from case reports.
REFERENCES
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