Maximizing Success with Peritoneal Dialysis: Best Demonstrated Practices

Peritoneal dialysis offers unique advantages for patients with ESRD. Peritoneal dialysis offers the convenience of home dialysis, allows continuous solute and fluid removal, and, for the incident dialysis patient, appears to be less harmful to residual kidney function (RKF). Many peritoneal dialysis patients have successfully used the therapy for a decade or longer without significant problems. To maximize success with peritoneal dialysis, providers must carefully attend to its many components. Preserving RKF, maintaining peritoneal membrane function, preventing cardiovascular disease, and avoiding infectious complications are all crucial components of therapy.

Preserving residual kidney function

It has long been recognized that peritoneal dialysis is associated with a slower decline in RKF than hemodialysis. Studies have also demonstrated that preservation of RKF correlates with improved survival. RKF allows for increased volume removal as well as improved phosphorus and middle molecule clearance. To preserve RKF, providers need to minimize nephrotoxic medications (e.g., intravenous contrast medium, nonsteroidal anti-inflammatory drugs), avoid rapid fluid shifts and hypovolemia, and, whenever possible, treat with blockers of the renin-angiotensin system. Two small randomized trials have shown that angiotensin converting enzyme inhibitors and angiotensin receptor blockers can minimize the loss in RKF (1,2). It is therefore recommended that patients with RKF receive either of these agents, assuming there are no contraindications.

Maintaining peritoneal membrane function

For peritoneal dialysis to be successful, adequate ultrafiltration is essential. However, in many peritoneal dialysis patients, anatomical changes in the peritoneal membrane affect ultrafiltration. Currently, a leading hypothesis posits that prolonged exposure over time to bioincompatible peritoneal solutions (high glucose, high glucose degradation products, low pH) damages mesothelial cells lining the peritoneum and increases vascularity of the peritoneum. Consequently, over time, many patients will have more rapid solute transport, quicker dissipation of the glucose-induced osmotic gradient, and less ultrafiltration. Given the available data, it seems prudent to minimize glucose exposure during dwells. Furthermore, salt restriction and judicious use of diuretics can reduce the need for hypertonic solutions. Recently, more biocompatible solutions (normal pH or low glucose degradation products) have been studied in small trials. To date, however, these trials have not conclusively determined whether biocompatible solutions preserve peritoneal membrane function, and their routine use cannot yet be recommended. Further data are necessary.

Preventing cardiovascular disease

As is true of patients receiving hemodialysis, cardiovascular disease is the primary cause of death in peritoneal dialysis patients. The majority of patients beginning dialysis have evidence of left ventricular hypertrophy (LVH) that correlates with an increased risk of sudden cardiac death. Hypertension and chronic volume overload likely contribute to LVH. Randomized controlled trials comparing a daily icodextrin dwell with a dextrose dwell have shown improved ultrafiltration and LVH. Peritoneal dialysis providers must use a comprehensive care plan to help patients remain euvolemic. Dietary sodium restriction, diuretics, and icodextrin (in appropriate patients) are all components of this care plan.

In some patients, atherosclerotic coronary disease contributes to the increased risk of cardiac death. The SHARP study, a trial comparing ezetimibe/simvastatin with placebo in chronic kidney disease and dialysis patients, enrolled 496 patients in peritoneal dialysis. Although there was a trend toward reduced atherosclerotic events in the treatment group, it was not statistically significant (3). By contrast, observational U.S. Renal Data System data from Dialysis Morbidity and Mortality Study wave 2 do indicate a significant decrease in both all-cause and cardiovascular mortality in peritoneal dialysis patients using lipid-lowering therapy (4). We routinely treat our peritoneal dialysis patients with lipid-lowering therapy targeting low-density lipoprotein <100 mg/dL.

Avoiding infectious complications

Both peritonitis and refractory infections of the exit site or tunnel are associated with significant morbidity. Catheter loss, ultrafiltration failure, and death are all associated with peritonitis. To minimize the risk for peritonitis, proper patient training and sterile technique are essential. Controlled trials have also shown that local antibiotic prophylaxis at exit sites, such as gentamicin cream or mupirocin, can reduce the risk of peritonitis and should therefore be routinely used.

In conclusion, peritoneal dialysis is a well-tolerated treatment for ESRD patients. Paying attention to these aspects of therapy will maximize the chances of successful peritoneal dialysis.

Notes

[1] Seth B. Furgeson and Isaac Teitelbaum are with the division of renal diseases and hypertension at the University of Colorado Anschutz Medical Campus in Aurora, CO, and Seth Furgeson is with the renal division at Denver Health Hospital.

References

1.Li PK, Chow KM, Wong TY, et al. Effects of an angiotensin-converting enzyme inhibitor on residual renal function in patients receiving peritoneal dialysis. A randomized, controlled study. Ann Intern Med 2003: 139: 105–112.

2.Suzuki H, Kanno Y, Sugahara S, Okada H, et al. Effects of an angiotensin II receptor blocker, valsartan, on residual renal function in patients on CAPD. Am J Kidney Dis 2004; 43: 1056–1064.

3.Baigent C, Landray MJ, Reith C, et al. The effects of lowering LDL cholesterol with simvastatin plus ezetimibe in patients with chronic kidney disease (Study of Heart and Renal Protection): a randomised placebo-controlled trial. Lancet 2011, 377:2181–2192.

4.Goldfarb-Rumyantzev AS, Habib AN, Bair BC, et al. The association of lipid-modifying medications with mortality in patients on long-term peritoneal dialysis. American journal of kidney diseases: the official journal of the National Kidney Foundation 2007; 50: 791–802.

August 2012 (Vol. 4, Number 8)