Continuous Ambulatory Peritoneal Dialysis and the Heart

Objective

To review clinical research pertaining to continuous ambulatory peritoneal dialysis (CAPD) and the heart.

Data Sources

A Medline computer search was employed to identify appropriate references from 1970 1994. Indexing terms were: continuous ambulatory peritoneal dialysis, hemodialysis, heart or cardiac, left ventricle, coronary artery disease, and survival. English and non-English language abstracts were scrutinized.

Study Selection

Forty-six studies were reviewed and utilized. Numerical data extracted are reported in this review as they were reported in the original article.

Results

This review provides a broad-based survey of studies pertaining to CAPD and the heart. Most of the studies relate to CAPD and left ventricular structure or function. Little information exists concerning CAPD and coronary artery disease, valvular disease, pericardial disease, and cardiac arrhythmias. Studies pertaining to patient survival on CAPD identify coronary artery disease and congestive heart failure as major risk factors, but in-depth quantification of these cardiovascular disorders is lacking in the literature.

Conclusions

CAPD is capable of decreasing left ventricular (LV) volume and improving LV systolic function in patients with L V enlargement and those with L V systolic dysfunction. The effect of CAPD on left ventricular hypertrophy (LVH) and LV diastolic function is variable. CAPD produces symptomatic improvement in patients with refractory congestive heart failure, but its effect on survival in such patients is uncertain. Atherogenic lipid abnormalities occur in CAPD patients. The clinical significance of these abnormalities is uncertain. Coronary artery bypass surgery can be performed safely and effectively on CAPD patients. CAPD is not arrhythmogenic. Survival of CAPD patients is similar to that of hemodialysis patients except in elderly diabetics for whom it is slightly lower.

Interrelationship between Cardiac Structure and Function and Incidence of Arrhythmia in Peritoneal Dialysis Patients

Cardiovascular complications in patients with end-stage renal disease requiring dialytic therapy are frequent and account for approximately 40% of all deaths in these patients. The aim of this study was to analyze the occurrence of cardiac arrhythmia in peritoneal dialysis (PD) patients with respect to the changes in left ventricular structure and function. To determine characteristics of arrhythmia in patients on PD for chronic renal failure, 30 patients (18 male and 12 female; aged 54.1±13.8 years) underwent twice (interval of 20±4.1 months) ambulatory 24 hour Holter ECG monitoring. At the same time all the patients were analyzed by echocardiography and pulsed Doppler echocardiography to estimate cardiac structure and function. Ventricular arrhythmias were seen in 9 patients (30%) during the first examination and in 13 patients (43.3%) on the second. Ventricular arrhythmias were observed only in patients with left ventricular hypertrophy (LVH). Supraventricular arrhythmias were seen in 12 (40%) and 17 (56.7%) patients. The majority of these patients also had LVH, with 11/12 (91.7%) patients at the first examination and 15/17 (88.2%) at the second respectively. We conclude that the incidence of arrhythmia is primarily dependent on the presence of LVH in PD patients. It appears that peritoneal dialysis does not provoke or aggravate arrhythmia.

Morbidity and mortality in redefining adequacy of peritoneal dialysis: a step beyond the National Kidney Foundation Dialysis Outcomes Quality Initiative

The National Kidney Foundation Dialysis Outcomes Quality Initiative (NKF-DOQI) Peritoneal Dialysis (PD) Adequacy Work Group intentionally limited the scope of its work to address adequacy in terms of small-solute removal. This decision was based on the need for rigorous evidence and that mortality is the most objective parameter in the literature. This review attempts to more broadly redefine the concept of the adequacy of PD, particularly as it relates to the most common general medical problems that PD patients experience; namely, cardiovascular disease and malnutrition. Whereas we are sensitive to the developmental process of the NKF-DOQI, we are critical that the definition of adequacy may be too narrow, leading clinicians to overlook other important morbidities. We have reiterated the evidence that suggests a weekly solute clearance (Kt/Vurea) of 1.7 or greater is associated with better patient survival. The arguments to target a greater Kt/Vurea of 2.0 are challenged, yet the concept is ultimately supported. Because cardiovascular disease is the cause of death in half of all patients with end-stage renal disease, dialysis adequacy must be defined, in part, by the potential of that therapy to diminish cardiovascular maladies. Blood pressure, volume, left ventricular hypertrophy, and dyslipidemias are discussed in this context. Lastly, assumptions that increasing total solute clearance leads to improved nutrition in PD patients are challenged. We have attempted to expand on what the NKF-DOQI did not include, and we urge the dialysis community to seek the answers to the many controversies that remain. We need to redefine the adequacy of PD in a holistic manner and find outcome parameters that are not as final as death.