In the 1960s, silicone rubber was found to be less irritating

Proceedings of the ISPD 2006 The 11th Congress of the ISPD 0896-8608/07 $3.00 +.00 August 25 29, 2006, Hong Kong Copyright 2007 International Society for Peritoneal Dialysis Peritoneal Dialysis International, Vol. 27 (2007), Supplement 2 Printed in Canada. All rights reserved. RATIONAL CHOICE OF PERITONEAL DIALYSIS CATHETER Roberto Dell Aquila, Stefano Chiaramonte, Maria Pia Rodighiero, Emilia Spano, Pierluigi Di Loreto, Catalina Ocampo Kohn, Dinna Cruz, Natalia Polanco, Dingwei Kuang, Valentina Corradi, Massimo De Cal, and Claudio Ronco Department of Nephrology, Dialysis, and Transplantation, St. Bortolo Hospital, Vicenza, Italy In the 1960s, silicone rubber was found to be less irritating to the peritoneal membrane than other plastics were, and in 1968, Tenckhoff and Schechter used a polyester-felt cuff to safely seal the catheter to the tissues, reducing the occurrence of leakage. This innovation was the most important in the history of peritoneal access devices. The Tenckhoff catheter became the gold standard of peritoneal access. Some of the original recommendations for catheter insertion such as an arcuate subcutaneous tunnel and downward direction of both the intraperitoneal and external exits are still considered very important elements of catheter implantation. From 1968 to the present time, many attempts have been made to reduce catheter-related complications such as displacement, catheter survival, cuff extrusion, leakage, exit-site infection, and peritonitis (Table 1); however, none of the devices currently used is troublefree. The peritoneal catheter should be a permanent and safe access to the peritoneal cavity. Catheter-related problems are often the cause of permanent transfer to hemodialysis (HD) in up to 20% of peritoneal dialysis (PD) patients; in some cases, these problems require a temporary period on HD. Advances in connectology have reduced the incidence of peritonitis, and so catheter-related complications during PD have become a major concern. In the last few years, novel techniques have emerged in the field of PD: new dialysis solutions, better connectology, and cyclers for automated PD. However, extracorporeal dialysis has continued to improve in terms of methods and patient survival, but PD has failed to do so. The main reason is that peritoneal access has remained problematical. The peritoneal catheter is the major obstacle to widespread use of PD. Overcoming catheter-related problems means giving a real chance to development of the peritoneal technique. Catheters should be as efficient, safe, and acceptable as possible. Since its introduction in the mid-1960s, the Tenckhoff catheter has not become obsolete: dozens of new models have been proposed, but none has significantly reduced the predominance of the first catheter. No convincing prospective data demonstrate the superiority of any peritoneal catheter, and so it seems that factors other than choice of catheter are what affect survival and complication rates. Efforts to improve peritoneal catheter survival and complication rates should probably focus on factors other than the choice of catheter. The present article provides an overview of the characteristics of the best-known peritoneal catheters. Perit Dial Int 2007; 27(S2):S119 S125 www.pdiconnect.com KEY WORDS: Peritoneal catheter; survival; peritonitis; continuous flow peritoneal dialysis; dislocation; exitsite infection; complications; catheter removal. Corresondence to: R. Dell Aquila, Department of Nephrology, Dialysis, and Transplantation, St. Bortolo Hospital, 37 Rodolfi Avenue, Vicenza 36100 Italy. roberto.dellaquila@ulssvicenza.it TABLE 1 The Most Commonly Used Catheters, by Inner and Outer Shaft Shape Straight and coiled Tenckhoff catheters Straight Straight with discs (TWH) Straight with weight (Di Paolo) Straight short (Vicenza Cath) Coiled Baloon (Valli) T-fluted (Ash) Swan-neck catheters Swan-neck abdominal catheters Swan-neck Tenckhoff straight and coiled Swan-neck Missouri straight and coiled Moncrief Popovich catheter Swan-neck presternal catheter Swan-neck Missouri catheter S119

PROCEEDINGS OF THE 11TH CONGRESS OF THE ISPD JUNE 2007 VOL. 27, SUPPL 2 PDI CHRONIC PERITONEAL CATHETERS Currently, the method of catheter placement has more effect on outcome than does choice of catheter (1). Four designs characterize the intraperitoneal portion of various catheters (2): Straight Tenckhoff, with an 8- or 16-cm portion containing side holes (the 16-cm with or without a 12-g tungsten weight at the tip) Coiled Tenckhoff, with a coiled 16-cm portion containing side holes Straight Tenckhoff, with perpendicular silicone discs [Toronto Western Hospital (TWH) or Oreopoulos Zellerman catheter] T-fluted catheter [Ash Advantage (Ash Advantage Technology, Lafayette, IN, U.S.A.)], a T-shaped catheter with grooved limbs positioned against the parietal peritoneum The subcutaneous portion of the catheter between the muscle wall and the skin exit site takes one of three basic shapes: Straight or straight with a gentle curve A permanent 150-degree bend or arc (swan-neck catheter) A permanent 90-degree bend, with another 90-degree bend at the peritoneal surface (Cruz catheter) Three positions and designs are seen for the polyester cuffs: Single cuff around the catheter, usually placed in the rectus muscle, but sometimes on the anterior surface of the rectus (depending on the procedure used to implant the catheter) Dual cuffs around the catheter, one in the rectus muscle and the other in subcutaneous tissue Disc-ball deep cuff, with parietal peritoneum and posterior rectus sheath sewn between a polyester disc and a silicone ball, and a second subcutaneous cuff (TWH and Missouri catheters) Adult PD catheters have three possible internal diameters, all with an outer diameter of approximately 5 mm (Figure 1): 2.6 mm, the standard size of the Tenckhoff catheter, swan-neck catheter, Missouri swan-neck catheter, and TWH catheter 3.1 mm (Cruz catheter) S120 A B C D Figure 1 Comparison of cross-sectional dimensions of the intraperitoneal portions of several peritoneal catheters. (A) Flex-Neck Tenckhoff catheter, silicone (Medigroup, Oswego, IL, U.S.A.); (B) Cruz Tenckhoff catheter, polyurethane; (C) Standard Tenckhoff catheter, silicone; (D) One intraperitoneal limb of the T-fluted catheter (Ash Advantage: Ash Advantage Technology, Lafayette, IN, U.S.A.), silicone. From S. Ash, with permission. 3.5 mm [Flex-Neck (Medigroup, Oswego, IL, U.S.A.) and Ash Advantage catheters] Two main materials are used in catheter construction: Silicone rubber (nearly all catheters) Polyurethane (Cruz catheter) A study by Nielson demonstrated a longer 3-year survival for coiled Tenckhoff catheters than for the straight models (3). If properly placed, dual-cuff Tenckhoff catheters have a lower incidence of exit-site infection and a longer lifespan than do single-cuff catheters (4). Coiled Tenckhoff catheters have a lower incidence of outflow failure than do straight catheters. Swan-neck catheters appear to have a lower incidence of exit-site infection than do those with straight subcutaneous segments (5). The Swan-Neck Presternal Catheter: The swan-neck presternal catheter is composed of two silicone rubber tubes joined by a titanium connector. The exit site is located in the parasternal area. The catheter location on the chest was designed to reduce the incidence of exit-site infection, and presternal catheters tend to perform better than swan-neck abdominal catheters do with regard to exit-site and tunnel infection. Useful in obese patients [body mass index (BMI) > 35], with rates of infectious complications and of survival superior to those of other catheters, the 2-year and 3-year survival rates of these catheters are 95% and 86% respectively. Recurrent peritonitis tends to be the only cause of failure. However, the implantation technique is more challenging than for single-piece abdominal catheters (6). The Ash Advantage Catheter: The Ash Advantage catheter (Figure 2) assures a stable position without extrusion of the deep cuff or exit-site erosion (7,8) and demonstrates a 1-year survival of 90%. During follow-

PDI JUNE 2007 VOL. 27, SUPPL 2 PROCEEDINGS OF THE 11TH CONGRESS OF THE ISPD Figure 2 The Ash Advantage catheter (Ash Advantage Technology, Lafayette, IN, U.S.A.). From S. Ash, with permission. up of 42 patients with Ash Advantage catheters in place for up to 4 years, only 1 patient developed a pericatheter leak and no patient developed a pericatheter hernia or late exit-site infection. The PD fluid outflow rate is, on average, equal to the best-functioning Tenckhoff catheters (including the large internal diameter Flex- Neck catheters). Negative aspects of the Ash Advantage catheter include a somewhat more complicated insertion procedure and a potential for blockage of the small openings between the fluted limbs and the central T-portion if the peritoneal fluid contains a considerable amount of blood or fibrin. The Ronco Catheter for Continuous Flow Peritoneal Dialysis: Continuous-flow PD (CFPD) may represent a new dialysis option, especially for patients with limited chances on standard continuous ambulatory PD or automated PD schedules. The CFPD technique permits an exploration of the effects of high-dose PD treatment with new and potentially beneficial effects (1,9 15). Double-lumen catheters with one short and one long branch in straight and spiral shapes were originally designed. Ash and coworkers designed a T-shape catheter to maximize the distance between the tips of the two lumens. Recently Ronco, Dell Aquila, Gloukhoff Wentling, Amerling, Cruz, and Levin designed a novel catheter for CFPD (16,17) with a double cuff and a thin-walled silicone diffuser to gently diffuse the inflow dialysate into the peritoneum. To eliminate the problem of recirculation, the diffuser design and hole locations (Figure 3) disperse the high-flow dialysate fluid at 360 degrees, reducing trauma to the peritoneal walls and allowing the dialysate to mix into the peritoneal cavity. The infused fluid so dispersed is then drained through the second lumen, whose tip is placed into the lower Douglas cavity. Additional design elements include a new tunnelizer and a removable hub with two spikes (adapted to the Figure 3 The Ronco catheter for continuous flow peritoneal dialysis. double-lumen cannula) to be applied after the catheter has been extracted from the skin through an adequate small hole. The results so far achieved seem to offer advantages in terms of high flows, minimal-pressure regimes, and negligible recirculation. This novel catheter was tested against other catheters to determine whether the new design had improved flow versus gravity and recirculation. Average recirculation was measured at 1.5%, and average flow at about 350 ml/min. The catheter was authorized for compassionate use in a 86-year-old man and produced encouraging results in terms of urea and creatinine clearances. Importantly, after its use in CFPD, this catheter can easily be used for automated PD by employing just one of the two lumens, suggesting that this catheter could theoretically be placed in every patient and be used for CFPD only when needed. The TWH Catheter: In a recent work by Sikaneta et al. (18), 192 patients receiving PD therapy with a TWH catheter were studied. With catheter removal being considered a failed or a censored event depending on whether the reason for the removal was peritonitis or another reason, the 1- and 3-year actuarial survival rates were 0.8536 and 0.7406, and 0.9182 and 0.9182 respectively. No difference in the survival rate was observed between diabetic and non-diabetic patients, between men and women, and between patients older or younger than 65 years. A total of 349 catheter complications occurred during 4845.3 catheter months of follow-up. Two or more episodes of peritonitis were seen with 38 of the catheters. Recurrent, refractory, fungal, or tuberculous S121

PROCEEDINGS OF THE 11TH CONGRESS OF THE ISPD JUNE 2007 VOL. 27, SUPPL 2 PDI peritonitis led to the removal of 27 catheters. Two or more exit-site infections occurred with 26 of the catheters. A total of 67 catheters became obstructed, with 7 catheters developing obstructions more than once. After intervention failed to relieve an obstruction, 9 catheters had to be replaced; intervention was successful for the other 57 catheters. Malfunction was diagnosed and led to catheter replacement in 8 cases. The leaks that occurred in 5 catheters developed at an average of 30.9 months after catheter insertion. The authors concluded that most studies have shown results similar to those of TWH catheters (19,20). It therefore seems likely that factors other than catheter choice are what affect survival and complication rates. Indeed, the absence of convincing prospective data demonstrating superiority for any peritoneal catheter has led some authors to suggest that practical considerations such as cost or availability be the factors that govern catheter choice (21). The Self-Locating Catheter: The self-locating catheter, designed by Di Paolo, has been increasingly used in Italy and elsewhere since 1994. Currently, about a thousand patients are implanted with this catheter every year. Twelve grams of tungsten inserted in the tip of the conventional Tenckhoff catheter (Figure 4) keep the tip firmly in the Douglas cavity (22 25). A multicenter controlled study lasting 24 months was conducted in 16 Italian nephrology departments with 962 uremic patients on PD, 216 of whom (representing 2678 patient months) were implanted with Tenckhoff catheters and 746 of whom (representing 10,444 patient months) received self-locating catheters (26). The annual number of displacements, the catheter life in months, and the annual number of cuff extrusions, leakages, exit-site infections, peritonitis episodes, and peritoneal sclerosis events were assessed. The results showed a statistically significant reduction in displacements, peritonitis, tunnel infection, cuff extrusion, obstruction, and early and late leakage with the self-locating catheter. The Vicenza Short Peritoneal Catheter: The Vicenza catheter (Figure 5) is a modified double-cuff straight Tenckhoff catheter with a inner shaft 8 cm in length instead of the normal 15 cm (27,28). From 1985 until the end of 2005, our group implanted a total of 726 Vicenza catheters. In a recent study, 701 catheters were evaluated in terms of removal rate for infection, removal rate for infection in obese patients, catheter dislocation, body image acceptance, and catheter wearability (29). From among the 701 catheters, a prospective analysis was carried out on 233 catheters implanted during 1995 2000, with particular regard to catheter survival at 5 years. Catheter survival was 94.3% and 91.5% at 2 and 5 years respectively. This high survival rate is probably attributable to our meticulous attention to exit-site care and early antibiotic treatment of infections. Furthermore, to prevent major complications, routine ultrasound examination of the exit-site and subcutaneous tunnel are performed [Figure 6(a,b)]. From 1985 to 2005, annual infections per patient decreased to 0.2 from 0.7 and catheter removals per patient year decreased to 0.03 from 0.63. These data demonstrate that promotion of good exit-site care is one of the most important factors in reducing the incidence of infectious complications and catheter removal (30). All patients with a BMI > 35 underwent catheter removal. An explanation may be that the subcutaneous cuff in these patients was located in fat tissue where the fibroblastic process is absent. For that reason, we recently modified the Vicenza catheter (Figure 7) to create a 20-cm distance between the two cuffs. To the time of writing, we had implanted only one of these new devices, Figure 4 Di Paolo self locating peritoneal dialysis catheter. S122 Figure 5 The Vicenza short catheter compared with the classical Tenckhoff.

PDI JUNE 2007 VOL. 27, SUPPL 2 PROCEEDINGS OF THE 11TH CONGRESS OF THE ISPD A B Figure 6 Ultrasound examination of the subcutaneous cuff of a Vicenza catheter in place: (A) longitudinal section; (B) cross section. Note the presence of hypo-echogenic areas. and more data are needed to determine if the modified catheter achieves longer survival in obese patients. In 1986, our 26 prevalent patients had a catheter dislocation rate of 22%; in 2005, we encountered only 4% displacements in 102 prevalent patients. Three years before the time of writing, we had evaluated 27 abdominal X-ray examinations of malfunctioning devices and observed that catheters with an exit site on the patient s left abdomen had a higher rate of migration (18/27) than did those with an exit site on the patient s right abdomen (9/27). In the latter cases of displacement, repositioning was easier after enhancement of peristalsis: the clockwise direction of the peristalsis helped to reposition the tip of the catheter. Figure 8(a,b) shows the best result we obtained. These findings explain the trend displayed over the last 3 years. Figure 7 Modified Vicenza catheter for obese patients: the distance between the cuffs is 20 cm. A B Figure 8 Abdominal X-ray of a displaced Vicenza catheter (A) before and (B) after enhancement of peristalsis (31). The exit site was placed on the patient s right side. S123

PROCEEDINGS OF THE 11TH CONGRESS OF THE ISPD JUNE 2007 VOL. 27, SUPPL 2 PDI Finally, we conducted a survey of patient satisfaction and quality of life: because of the catheter insertion position, patients declared good body image acceptance (98%) and excellent wearability (100%). CONCLUSIONS Even if certain catheter shapes have demonstrated better performance in terms of survival and reduction of displacements, peritonitis, tunnel infection, cuff extrusion, obstruction, and early and late leakage, none of the catheters discussed here and most commonly used in practice are completely free from complications. Some authors emphasize the importance of catheter design, but other conditions are probably leading to the reported complications. Special attention must be given to care of the catheter in the hospital and at home. 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