(CHG) to decrease hemodialysis (HD) - Wiley Online Library

Hemodialysis International 2005; 9: 70–103

Hemodialysis Abstracts from the Annual Dialysis Conference 25th Annual Conference on Peritoneal Dialysis, 11th International Symposium on Hemodialysis, and 16th Annual Symposium on Pediatric Dialysis Tampa, Florida February 28–March 2, 2005

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2005 International Society for Hemodialysis

Hemodialysis International, Vol. 9, No. 1, 2005

25th Annual Dialysis Conference: Abstracts

Access High output heart failure in patients with upper arm A-V fistulae: Diagnosis and treatment

Cutting balloon angioplasty for resistant venous stenoses in hemodialysis patients

Amerling R., Malostovker I., Dubrow A., Rosero H., Haveson S. Division of Nephrology and Hypertension, Division of Cardiology, Division of Vascular Surgery, Beth Israel Medical Center, New York, NY.

Jung H.W., Kim Y.O., Song H.H.*, Park J.A., Kim Y.S., Kim S.Y., Choi E.J., Chang Y.S., Bang B.K. Dept. of Int. Med., Radiology*, College of Medicine, The Catholic University of Korea, Seoul, Korea.

Purpose: Arteriovenous fistula (AVF) is the preferred blood access for hemodialysis due to its longevity and resistance to infection. Little attention is given to the long-term hemodynamic consequences of large left-to-right shunts, particularly in patients with brachial artery fistulae. Materials and Methods: We describe 9 patients (8 on dialysis, 1 post-transplant), aged 25–73, who developed clinical heart failure, primarily due to large, upper arm AVFs. Results: 4/9 had access flows in excess of 2 liters/ min, assessed by blood temperature monitoring. 6/9 had cardiac output measured by right heart catheterization, before and after shunt compression. One also underwent left heart catheterization with ventriculography. 3/9 had surgical reduction of the fistula, either by banding or by serial interposition of small caliber GoreTex graft. In 2/9 the shunt was ligated. One patient had heart failure in association with 2 large, upper arm AVFs, one of which was ligated. After years of improved cardiac symptoms, heart failure recurred in association with marked hypertrophy of his remaining AVF. Resting cardiac output in this patient was in excess of 11 liters/min. 2/9 experienced acute onset of heart failure within 1–3 days of angioplasty of a venous stenosis. One of these, with very poor baseline cardiac function, expired. Surgical revision or ligation was accompanied by clinical improvement in the 5 patients so treated. One of these expired of a stroke after two months of cardiac improvement. Conclusion: High output heart failure is under-diagnosed in dialysis patients. Patients with large upper arm shunts are particularly at risk. Access flow should be assessed regularly and those with outputs >1.5 liters/min should be monitored closely for development of heart failure. Surgical correction is beneficial and indicated in symptomatic patients.

Purpose: To report our initial experience of using cutting balloons angioplasty in the treatment of resistant venous stenoses of Brescia-Cimino fistulas. Materials and Methods: Forty-eight patients with Brescia-Cimino fistulas underwent percutaneous transluminal angioplasty (PTA) of 62 venous stenoses. Of these 48 patients, we encountered 8 venous stenoses (8/62, 12.9%) in 7 patients that were not successfully dilated with 6–8 mm highpressure balloons inflated up to 24 atm. In each of 8 stenoses, peripheral cutting balloons with diameters of 5–8 mm were employed to dilate resistant stenoses. Results: The locations of stenoses were 3 at the surgical vein mobilization site (‘‘swing point’’), 4 at the cephalic vein downstream from the anastomosis, and 1 at the cephalic arch. The grade of stenosis after highpressure balloon angioplasty ranged from 57% to 87% (mean, 76%). Cutting balloons expanded completely in all stenoses and the residual stenosis after cutting balloon PTA ranged from 0% to 24% (mean, 7%). Residual stenosis was virtually nonexisistent at the 3 stenoses of ‘‘swing point.’’ A focal rupture with a large hematoma occurred at the cephalic arch stenosis, which was treated by a stent placement. One minimal rupture that did not require any treatment occurred at the stenosis of downstream cephalic vein. No repeat angioplasty has been needed during follow-up period (range, 74–249 days). Conclusion: Our early experience demonstrated that when high-pressure balloons fail to dilate stenoses of Brescia-Cimino fistulas, peripheral cutting balloons with diameters of 5–8 mm can be effectively used to overcome the resistance of stenoses.

Years Flow Change Patient Age/ Access with (liters/ CO (liters/ number Sex type access min) min) Rx 1 2 3 4 5 6 7 8 9

37/M 26/M 73/M 45/M 65/M 57/F 39/F 66/M 69/F

AVF AVF AVF AVF AVF AVG AVF AVG AVF

8 5 3 10 4 4 2 0.3 0.25

>2 >2 >2 n/a >2 1.2 n/a 0.7 n/a

1.7 2.4 1.5 3.2 2.8 1.8 n/a n/a n/a

Outcome

Reduction Band Reduction Reduction Band

Improved Improved Improved Improved Improved

Ligate Ligate

Improved Improved Expired

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Efficacy of percutaneous angioplasty in non-maturing Brescia-Cimino fistulas Kim Y.S., Kim Y.O., Song H.H.*, Jung H.W., Park J.A., Yoon S.A., Lee S.H., Chang Y.S., Bang B.K. Dept. of Int. Med., Radiology*, College of Medicine, The Catholic University of Korea, Seoul, Korea.

Purpose: To evaluate efficacy of percutaneous transluminal angioplasty (PTA) in non-maturing Brescia-Cimino fistulas. Methods: Between January 1997 and December 2003, we treated 22 patients with non-maturing Brescia-Cimino fistulas by PTA. Retrospective analysis was performed on the findings of fistulogram, techniques and success rate of PTA, and patency rate. Results: Seventeen segmental stenoses and 5 segmental occlusions of cephalic veins were identified. Sixteen stenoses and 2 occlusions were located at the cephalic vein adjacent to the anastomosis site, and 3 occlusions and 1 stenosis were seen

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at the proximal vein near the elbow joint. In addition to venous stenosis, a focal arterial stenosis at the anastomosis site and two accompanying accessory veins that might hamper maturation of main cephalic vein was seen in each of two patients, respectively. Simultaneous occlusion of left innominate vein as well as occlusion of cephalic vein were noted in one patient. Initial success rate of PTA was 95.5% (21/22). Overall success rate including 11 additional PTAs performed during follow-up was 96.9% (32/33). No major complication occurred. Primary and secondary patency rates were 72% and 95% at 3 months, and 50% and 77% at 6 months, respectively. Conclusion: PTA is an effective and safe method in salvaging non-maturing BresciaCimino fistulas.

Intima-media thickness of radial artery is associated with early access failure in hemodialysis patients Kim Y.O., Choi Y.J.*, Kim J.I.**, Shin M.J., Kim B.S., Song H.C., Yoon S.A., Kim Y.S., Kim S.Y., Choi E.J., Chang Y.S., Bang B.K. Dept. of Int. Med., Clinical Pathology*, Surgery**, The Catholic University of Korea, Seoul, Korea.

Objective: We have reported that intimal hyperplasia, which is the pathologic change of the radial artery, is associated with early failure of arteriovenous fistula (AVF) in hemodialysis (HD) patients (Am J Kidney Dis, 41:422–428, 2003). Intimamedia thickness (IMT), which represents the whole thickness of arterial wall, can be easily measured by ultrasonography, unlike intima thickness. This study was performed to investigate the impact of IMT of radial artery on early failure of AVF in HD patients. Methods: Ninety HD patients undergoing radiocephalic AVF operation were included in this study. The AVF was constructed in an end vein–to–side artery fashion at the wrist by one vascular surgeon. During the operation, 10-mm long partial arterial walls were removed with elliptical form for microscopic analysis. Specimens were stained with trichrome and examined by a pathologist blinded to the clinical data. AVF patency was prospectively followed up for 1 year after the operation. Results: Mean age of the patients was 56 13 years and the number of females was 44 (48.9%). Mean IMT was 430 132 mm (133–760 mm). Of the total 90 patients, 31 patients (34.4%) had AVF failure within 1 year after the operation. Mean IMT was higher in the failed group (n ¼ 31) than in patent group (n ¼ 59) (486 130 mm vs. 330 178 mm, p ¼ 0.004). Using a threshold of 500 mm of IMT, AVF patency rate was compared between these two groups using Kaplan-Meier method with log rank test. The AVF patency rate within 1 year after the operation was higher in patients with IMT 500 mm (n ¼ 26) than in patients with IMT < 500 mm (n ¼ 64) (p < 0.001). The patients with IMT 500 mm were older and had higher incidence of diabetes mellitus, compared to the patients with IMT < 500 mm. There was no difference in sex, smoking, hypertension, total cholesterol and albumin levels between the two groups. Conclusion: Our data suggest that

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increased intima-media thickness of radial artery is associated with early failure of radiocephalic arteriovenous fistula in hemodialysis patients.

Central venous stenosis in chronic hemodialysis patients: The effect of percutaneous angioplasty and stenting Yoon J.M., Park J.A., Jung H.A., Kim Y.O., Kim Y.S., Yoon S.A., Kim S.Y., Chang Y.S., Bang B.K. Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.

Background: Central venous stenosis in chronic hemodialysis patients occurs in about 17% of all venous stenosis and it is associated with central vein catheterization. We evaluated the effect of percutaneous angioplasty and stenting in the treatment of central venous stenosis in hemodialysis patients. Methods: We retrospectively investigated the medical records of a total of 31 dialysis patients who had central venous stenosis. We reviewed the causes of central venous stenosis, clinical manifestations, venographic findings, and patency rate of radiological intervention. Results: Of the total 31 patients, 28 patients had past history of central vein catheterization ipsilateral to vascular access. Mean duration of the catheterization was 32 14 days. Venography showed complete obstruction of central vein (n ¼ 14) and stenosis (n ¼ 17). The site of venous lesion was right subclavian vein (n ¼ 11), innominate vein (n ¼ 9), left subclavian vein (n ¼ 7), and superior vena cava (n ¼ 14). A total of 30 procedures of angioplasty with or without stenting were performed in 26 of 31 patients. Initial success rate was 96.1% and there was no severe complication such as rupture or bleeding. The primary patency rate at 6, 12, 24, and 48 months after the procedure was 87.3%, 75.6%, 67.9%, and 65.4%, respectively. The cumulative patency rate at the same time point was 96.0%, 90.6%, 74.0%, and 72.8%, respectively. Conclusion: Our data suggest that angioplasty with or without stenting is safe and effective in the treatment of central venous stenosis in hemodialysis patients.

Effective interventions with chlorhexidine gluconate (CHG) to decrease hemodialysis (HD) tunneled catheter-related infections Redman N.1, Schweon S.1, Tokars J.2, Jahre J.1. St. Luke’s Hospital, Bethlehem, PA1; CDC, Atlanta, GA.2

Purpose: Identify practices to reduce HD catheter access related bacteremias (ARB). Methods: Data was collected per the CDC Dialysis Surveillance Network protocol. ARB was defined as a patient with a positive blood culture with no apparent source other than the vascular access catheter. ARB’s were calculated in events per 100 patient months with 3 cohorts. Cohort 1 was observed for 12 months, Cohort 2 for the subsequent 10 months, and Cohort 3 for the final 10 months. Cohort 1 had weekly

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transparent dressing changes, cleansing of the skin and 5 minute soaking of the connection lines with 10% povidone-iodine (PI) solution, and HCW use of clean gloves and face shield without a mask. Cohort 2 changes consisted of thrice weekly gauze dressing changes, skin cleansing with ChloraPrep, a 2% CHG/70% isopropyl alcohol applicator, masks on the patients, adding a face mask to the shield, and application of 10% PI ointment to the exit site. Cohort 3 changes included weekly application of BioPatch (BioP), an antimicrobial dressing with CHG, sterile glove use, and replacing the PI line soaks with 4% CHG. Results: The catheter-associated ARB rate per 100 patient months was 7.9 (17ARB/216 patient months) in Cohort 1, 8.6 (13/151) in Cohort 2, and 4.7 (5/107) in Cohort 3 (p ¼ 0.31 compared with Cohorts 1 and 2 combined). During the last 2 months, in Cohort 3, 9 catheter lumen cracks occurred, with one of the patients having a bacteremia. Conclusions: Addition of CHG line soaks and BioP reduced tunneled catheter infections, although this is not statistically significant. The increased number of catheter lumen cracks raises concern with the use of CHG line soaks. Further investigation with use of CHG line soaks and the BioP for decreasing ARB is needed.


cases it was necessary to perform a second attempt, and 2 cases required three operations. The second stage was undertaken in all of these patients (n ¼ 54), and complete success was achieved in 51. In 3 cases, in spite of superficialization, AVF was not suitable for puncturing because of poor blood flow. The causes of failure of the first stage procedure in 2 patients were severe arteriosclerosis and venous anomaly. All patients had non-altered cephalic veins in the wrist region, as opposed to patients with cannulated veins. In 51 pts (90%) an efficient flow of the blood through AVF was successfully obtained and allowed satisfactory dialyses. Conclusions: The primary AVF creation on the forearm is feasible in 90% of obese patients. This result is similar to the general population of chronic renal disease patients of our center (95%) (NDT 1998;13:527) and is possible thanks to the location of the veins deep in the subcutaneous fat tissue, which protects against repeated cannulation and hence mechanical destruction in the pre-dialysis period.

The economics and practicality of t-PA vs tunnel catheter replacement for hemodialysis Cairoli O. Kaiser Permanente. Bellflower, CA.

Obesity promotes forearm primary arteriovenous fistula creation in chronic haemodialyzed patients Weyde W., Porazko T., Kusztal M., Banasik M., Bartosik H., Trafidlo E., Letachowicz W., Krajewska M., Klinger M. Dept. of Nephrology and Transplantation Medicine, Wroclaw Medical University, Wroclaw, Poland.

The increase in number of obese people seen in the general population, is also what is seen in the hemodialyzed population. It is generally believed that the location of deep forearm vessels in the subcutaneous fat tissue makes primary arteriovenous fistula (AVF) a disadvantage because of difficulties in vessel puncturing. For obese patients, it is suggested that a fistula with PTFE is created or a central catheter inserted, but these solutions increase already high morbidity rate and significantly increase mortality rate. Methods: The deep location of veins situated on the anterior part of the forearm involved 57 patients (45 female and 12 male) aged 13–87 years (mean 67 15.2 years). Patients’ body mass index (BMI) ranged from 29.1 to 53.73 (mean 34.6 7.8). The causes of the renal failure were diabetic nephropathy in 30 patients, chronic glomerulonephritis in 4, hypertensive nephrosclerosis in 5, lupus nephritis in 2, interstitial nephritis in 4, primary amyloidosis in 1, polycystic kidney disease in 3, and unknown in 3 patients.Two-step surgical procedure was performed in all patients. In the first stage, the standard distal radiocephalic AVF in the wrist region was created. In case of its failure, the next attempt was performed above the point of the first intervention. In the second stage, superficialization of the venous part of AVF was performed in the mode described by us (Kidney 2002;.1:1170). Results: The first stage of the procedure was successful in 46 patients. In 6


Introduction: Thrombolytic therapy is an important treatment modality for thrombosis-related catheter occlusion. Central venous access devices (CAVDs) are essential tools for the administration of many therapeutic modalities, especially for patients requiring lifetime therapy like hemodialysis. There are several reasons to salvage the occluded catheter. Catheter replacement results in an interruption of therapy delivery. This interruption may result in complications such as life-threatening metabolic and physiologic states. In addition, the patient’s future access sites for CAVDs may be affected. The data released in the 2001 Annual Report – ESRD Clinical Performance Measures Project (Department of Health and Human Services, December 2001) shows 17% of prevalent patients were dialyzed with a chronic catheter continuously for 90 days or longer. In the pediatric population the data shows that 31% were dialyzed with a chronic catheter. The most common reasons for catheter placement included: no fistula or graft created (42%) and fistula and graft were maturing, not ready to cannulate (17%). Five percent of patients were not candidates for fistula or graft placement as all sites had been exhausted. Methods: A short study was done in our medical center to evaluate the results of t-PA vs. changing the tunnel catheter. On an average a catheter costs about $400.00. If you add the cost of specialty personnel such as an interventional radiologist, radiology technician, radiology nurse, and the ancillaries such as the room, sutures, gauze, and tape, the total could reach $2000.00 easily. CathfloTM Activase1 costs around $60.00 for a single dose. T-PA was reconstituted by pharmacy personnel in single vials containing 2 mg/2 ml. Now with Cathflo, vials are stored in the renal clinic’s refrigerator and when the need arises, the RN reconstitutes the medication. The RN, using established protocols, will instill Cathflo in the catheter following the volume requirements of the various tunnel

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catheters. After the t-PA is placed, the patient is sent home with instructions to return to their dialysis center the next day (arrangements are made by the RN as needed). In seventeen patients (17) with tunnel catheter malfunctions due to inadequate flow, not related to placement, t-PA was used. Of those 17 patients 2 were unable to use their catheter on their next dialysis treatment date, yielding an 88% success rate. This compares with clinical trials in which there is an 83% success rate with a dwell time of 4 hours, or an 89% rate on patients having a 2 hour dwell time (t-PA was repeated a second time if flow was not successfully restored. Results: 15/17 patients in our retrospective study showed that Cathflo worked successfully in restoring blood flow. Two catheters needed to be exchanged. The cost savings were significant when we compared the average cost of an exchange ($2000) versus using t-PA ($170 including nursing time). Conclusion: Cathflo is not just safe and practical to use but also cost effective.

Shunt surveillance and occlusion, an analysis of efficiency Wijnen E. University Hospital, Maastricht, Netherlands.

Introduction: Vascular access failure is one of the greatest sources of morbidity for chronic hemodialysis patients. Prophylactic and repeated measurement of access flow may be of importance in preventing clotting. The aim of the study was therefore to analyse the cost effectiveness of a shunt surveillance program, which reduces the appearance of occlusion of the vascular access. Methods: The number of vascular access interventions (surgery and radiology) in the period 2001 till 2003 (transonic measurement period, TMP; 63 patients) was compared with a reference period (RP, 1996 till 1998) during which no access flow was measured (58 patients). All measurements were done with Transonic1 and interventions according to K/DOQI. Results: During the RP, 123 vascular access operations (0.71 per patient year) were performed because of occlusion, whereas in the TMP 58 vascular access operations (0.3 per patient year) were performed. During the TMP, 298 angiographic measurements were performed (1.6 per patient year) in the RP 177, (1.0 per patient year). In the TMP, 1652 access flow measurements were performed. In order to prevent one shunt occlusion, 21 access flow measurements had to be performed. Total costs in the TMP (summary of angiography, angiography and PTA, hospitalization days, and operation costs) are reduced with 31% compared to the RP; costs per patient year in RP: E2315. Costs per patient year in TMP: E1606. Conclusion: By means of a shunt surveillance program (based on access flow measurement), if necessary followed by angiography, it is possible to reduce the number of acute vascular access occlusions. Although a shunt surveillance program may take up a lot of time for the nursing staff, the beneficial effects, lower costs, and reduced morbidity for the patients outweigh this effort.

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Preliminary experience with a new design for a tunneled, cuffed catheter for hemodialysis Bousquet, G.C. Saints Memorial Medical Center, Lowell, MA.

Purpose: The use of tunneled, cuffed central venous catheters for hemodialysis is associated with poor flow, thrombosis, and infections due to the transcutaneous nature of these devices. A new design for a sutureless, tunneled cuffed catheter was evaluated in hemodialysis patients to determine the effect of its design on the incidence of exit site infection. Methods: A polyurethane conduit with a uniquely designed cuff and subcutaneous skirt covered with Dacron velour was attached to standard double lumen central venous catheters. Seven (7) Ash catheters and one (1) Tesio catheter were fitted with the overtube and skirt and implanted in eight (8) patients undergoing routine hemodialysis. Patients were monitored for exit site infection, tunnel infection, bacteremia, cuff extrusion, and serosanguineous exudate. Results: Catheters were implanted for 6 to 26 weeks. All catheters remained patent and no cases of bacteremia were observed. There was no evidence of exit site or tunnel infection, and no reported serosanguineous exudate from the exit site. Exit site care consisted of soap and water cleansing by the patient. Patients were able to shower or bathe 4 weeks post-implant. Conclusions: The new design for a subcutaneous cuff and skirt appears to inhibit exit site infection and other common complications of central venous catheters.

Sodium citrate as a capping for permacaths Scott G.E. Commonwealth Dialysis Center, Greenfield, WI.

Purpose: Tunneled catheters as chronic dialysis access is a reality of chronic hemodialysis. Infection of the catheter is an unavoidable complication. We researched the possibility of using Na Citrate as capping because of its anticoagulant effects and bactericidal properties. Methods: Rate of infections per 1000 calendar days with heparin capping was recorded for an eight month period before using Na Citrate. Flows FB130UGA > GA-HP130 > F6 > FB-130AGA > WS-70 in turn. The concentrations at different blood flow-rates were different 100 mL/min > 200 mL/min. Conclusions: The concentration of citrate in hollow fiber is affected by different types of hemodialyzers and different blood as well as dialysate flow-rates. To achieve anticoagulation when using citrate hemodialysate, we must select suitable hemodialyzer such as FB-130UGA.

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Dialyzer reuse and clinical outcomes—A 3-year comparison between high flux polysulfone and polyflux1 dialyzers Sorrill M.A. Blessing Hospital, Renal Dialysis, Quincy, IL.

Purpose: This study evaluated improvements in dialyzer reuse parameters and clinical outcomes associated with a CQI project in a hospital-based dialysis center in which high flux polysulfone dialyzers were replaced with high flux Polyflux1 dialyzers (GAMBRO1 Renal Products). Methods: Dialyzers were reprocessed using a Renatron1 II Dialyzer Reprocessing System in conjunction with Renalin1 sterilant (Minntech Corp.). Renalog1 RM software was used to track dialyzer reprocessing rates and failures. Reasons for dialyzer failure included inadequate dialyzer volume; excess pressure; appearance; clotting during use; and maximum number of uses reached. The average number of dialyzer reuses with polysulfone dialyzers between January and June 2002 were compared to that achieved with Polyflux1 dialyzers for the same periods in 2003 and 2004. Analysis periods were separated to avoid the impact of dialyzer transition on clinical parameters. Achievement of URR goals during these same periods was likewise compared. Results: Transition from polysulfone to Polyflux1 dialyzers was associated with a >40% increase in average number of reuses between 2002 and 2003 and a >63% increase comparing the 2002 and 2004 periods. During the 2002 analysis period with polysulfone dialyzers the target URR of 65% was achieved in approximately 75% of hemodialysis patients; this increased to nearly 95% with Polyflux1 dialyzers in both the 2003 and 2004 periods, despite more reprocessing of these dialyzers. Conclusions: These results demonstrate an improvement in both reuse efficiency and clinical outcomes associated with Polyflux dialyzers. Identifying clinical products through CQI studies that provide an economic and clinical advantage plays an important role in the success of hospital-based hemodialysis.

Tandem dialyzers with dual monitors to meet Kt/V targets Sridhar N., Hurst C., Hayes P. KaleidaHealth, Buffalo, NY.

Objective: A large body mass and/or a poorly functioning vascular access predispose to inadequate Kt/V. Double dialyzers in parallel and tandem have been shown to enhance Kt/V to levels recommended by K/DOQI. We experienced difficulties with unintended excessive ultrafitration (UF), positive transmembrane pressure (TMP)-triggered pump stoppage, need for large volume saline infusion (inflating Kt/V), and a high incidence of clotting of the second dialyzer in tandem. Since blood and dialysate flow rates are higher in the tandem configuration, Kt/V should be theoretically higher. We developed a technique of using the tandem configuration with two monitors in which all the UF could be limited to the second dialyzer, the TMP of the two dialyzers independently controlled, TMP reversal elimi-

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nated, and saline infusion and unintended UF minimized. Methods: 3 large male patients with AV grafts (AVG) and 2 with tunneled catheters (TC) had 7 treatments (with Kt/V and URR calculated using the stop-flow technique in the last 5) sessions of each of single, double parallel, and tandem configurations. Blood (Qb) and dialysate-flow (Qd) were halved with Y-connectors in the parallel configuration. Qb through both dialyzers and Qd through the second were controlled with the first monitor and Qd (TMP set to near zero) through the first dialyzer controlled with the second monitor using recirculating saline through its blood pump (with the ‘‘venous’’ pressure adjusted using an air-filled syringe) in the tandem configuration. The patient’s blood did not circulate through the blood-pump of the first machine. Qd was 500 ml/min through each dialyzer in the single and tandem and 250 ml/min in the parallel configurations. Processed blood volume (dialysis time) was exactly 85 L with AVG and 60 L with TC. Heparin dosage was constant. ANOVA, 2 k tables, and Neuman-Keuls test were used in analyzing data. Results: Mean Kt/V (%URR) increased from 1.15 (62) with single to 1.35 (68) with parallel (p < 0.02) and 1.48 (71) with tandem (p < 0.001) dialyzers in patients with AVG but not TC [1.05 (58), 1.02 (55), and 1.25 (64) with single, parallel, and tandem, respectively]. Tandem dialyzers met targets for URR (p < 0.001) and Kt/V ( p < 0.05) more frequently than parallel with AVG but not TC. Conclusions: Tandem dialyzers with 2 monitors are more successful than parallel dialyzers in delivering target Kt/V and URR when Qb is not compromised.

Impact of flow and surface area on middle molecule clearance Eloot S.1, De Vos J.Y.2, Hombrouckx R.2, Verdonck P.1 1Institute Biomedical Technology, Ghent University, Belgium, 2Dialysis Unit, AZ Werken Glorieux, Ronse, Belgium.

Urea is still clinically applied as standard marker to quantify dialysis adequacy. The removal of middle molecules has however been proven in some studies to have a long-term effect on mortality. Therefore, the present study is aimed at investigating the impact of blood and dialysate flow, and membrane surface area on middle molecule removal in low flux Fresenius F6HPS dialyzers. Blood and dialysate flows were varied within the clinical range of 300–500 mL/min and 500–800 mL/min, respectively, while ultrafiltration rate was kept constant at 0.1 L/h. Single pass tests were performed in vitro in a single dialyzer (3 tests) and in serially (5 tests) and parallel (3 tests) connected dialyzers. The blood substitution fluid consisted of bicarbonate dialysate in which radioactive labeled vitamin B12 (MW1355) was dissolved. Middle molecule concentrations of samples taken at the inlet and outlet blood line were derived from radioactivity measurements and were applied to calculate the dialyzer clearance as well as the reduction ratio. For the latter, the surrogate middle molecule vitamin B12 was assumed as distributed according to a two-pool kinetic model. Adding

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a second dialyzer in series or parallel ameliorates significantly overall dialyzer clearance and reduction ratio, except for the highest applied blood flow rate of 500 mL/min. Better solute removal is also obtained with higher dialysate flows, while the use of higher blood flows seemed only advantageous when using a single dialyzer. Analysis of the ultrafiltration profiles in the different configurations illustrated that enhancing the internal filtration rate ameliorates the convective transport of middle molecules. In conclusion, adequate solute removal results from a number of interactions, as there are, blood and dialysate flow rates, membrane surface area, filtration profile, and concentration profiles in the blood and dialysate compartment.

Impact of geometrical fiber dimensions on dialyzer efficiency Eloot S.1, Vierendeels J.2, Verdonck P.1 1Hydraulics Laboratory, 2 Fluid Mechanics Laboratory Institute Biomedical Technology, Ghent University, Belgium.

While dialyzer manufacturers only provide information about their products as a black box, this study aimed at optimizing dialyzer geometry by looking in detail at transport processes and fluid properties inside the dialyzer using numerical modeling. A three-dimensional computer model of a single hollow fiber with its surrounding membrane and dialysate compartment was developed. Different equations govern blood and dialysate flow (Navier-Stokes), radial filtration flow (Darcy), and solute transport (convection-diffusion). Blood was modeled as a non- Newtonian fluid with a viscosity varying in radial and axial direction because of the influence of local hematocrit, diameter of the capillaries, and local shear rate. Dialysate flow was assumed as an incompressible, laminar Newtonian flow with a constant viscosity. The permeability characteristics of the asymmetrical polysulphone membrane were calculated from laboratory tests for forward and backfiltration. The influence of the oncotic pressure induced by the plasma proteins was implemented as well as the reduction of the overall permeability caused by the adhesion of a protein layer on the membrane. Urea (MW60) was used as a marker to simulate small molecule removal, while middle molecule transport was modeled using vitamin B12 (MW1355) and inulin (MW5200). The corresponding diffusion coefficients were determined by counting for the fluid and membrane characteristics. Fiber diameter and length were changed in a wide range for evaluation of solute removal efficiency. The presented model allowed us to investigate the impact of flow, hematocrit, and capillary dimensions on the presence and localization of backfiltration. Furthermore, mass transfer was found enhanced for increased fiber lengths and/or smaller diameters, most pronounced for the middle molecules compared to urea.



Effect of dialyzer reprocessing on glucose homeostasis Ibrahim M.A., Labib B., Sallam* T., Sarhan I., El-Damasy H. Departments of Internal Medicine, Nephrology and Clinical Pathology*, Faculty of Medicine, Ain Shams University, Cairo, Egypt.

This study was designed to investigate the possible effect of dialyzer re-use on glucose hemostasis. Twenty patients with end stage renal failure (including ten non insulin dependent diabetes mellitus [NIDDM]) on thrice weekly hemodialysis (using glucose free dialysate), were studied by serial assessment of blood glucose, C-peptide, interleukin 1-B (IL-IB), Ca, Na and K at zero, 1 and 4 hours (end of dialysis) during hemodialysis on new, and then on re-used (first) cuprophane dialyzers. Our results showed significant rise of C-peptide, IL-1B with drop of blood glucose in first hour sample (and was symptomatic in some diabetics) in both groups when using new dialyzers but these changes were less marked and totally asymptomatic when using reprocessed dialyzers. In addition there was a significant positive correlation between IL-1B level and C-peptide at 1 and 4 hour samples and negative correlation between IL-1B and blood glucose at 1 and 4 hour samples. Conclusion: Through the effect of IL-1B on insulin release curophane dialyzers can affect glucose homeostasis especially in diabetics and hypoglycemia might be part of the first use syndrome. It may be recommended that measurement of glucose effect of dialysis membrane on glucose homeostasis might be an important parameter of membrane bioincompatibility.

Clearance of small molecules in different dialyzer flow configurations Eloot S.1, De Vos J.Y.2, Hombrouckx R.2, Verdonck P.1 1Institute Biomedical Technology, Ghent University, Belgium, 2Dialysis Unit, AZ Werken Glorieux, Ronse, Belgium.

To overcome problems of insufficient clearance, multiple dialyzers may be placed in series or in parallel. The present study aimed to investigate in vitro the overall clearance of small molecules in different dialyzer configurations in which mutual flow directions were changed. Single pass tests were performed with low flux Fresenius F6HPS dialyzers placed in series (12 tests), in parallel (6) and in single use (2). As blood substitute, either high concentrated (45 mS) bicarbonate dialysate (AB solution – MW20-180) or a trisodiumphosphate (Na3PO4 – MW395) concentration (30 mS) was used. Standard blood and dialysate flows of 250 and 500 mL/min, respectively, were applied. Furthermore, clearance was derived from conductivity measurements in the inlet and outlet bloodline, correcting for the overall ultrafiltration rate of 0.5 L/h (AB) and 0.1 L/h (Na3PO4). Compared to the standard setup using a single dialyzer with counter current flows, clearance increases by 3 to 8% (AB) and by 15 to 18% (Na3PO4) using two dialyzers in parallel and in

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series, respectively. With co-current flows in a serial dialyzer set up, clearance increases by 16% (AB) and 22% (Na3PO4) compared to the single dialyzer use. Changing subsequently the counter current flows to co-current in one and both dialyzers in series, the overall clearance decreases by 2 to 9%, respectively, for the AB solution, and by 8 to 15% for the Na3PO4 concentration. With respect to the parallel dialyzer setup, a split dialysate flow (250 mL/min in each dialyzer) counter current to the blood flow, increases the clearance by 4 and 12%, respectively. In conclusion, overall clearance is most ameliorated using two dialyzers in series with counter current flows.

Urea kinetics are not representative for the behavior of other small and water-soluble compounds Eloot S.1, De Smet R.2, Torremans A.3, De Wachter D.1, Marescau B.3, De Deyn P.P.3, Verdonck P.1, Vanholder R.2. 1 Institute Biomedical Technology, Ghent University, Belgium, 2 Nephrology Section, Ghent University Hospital, Belgium 3 Laboratory of Neurochemistry, University of Antwerp, Belgium.

Scanty data suggests that large solutes show a kinetic behavior that is different from urea. The question investigated in this study is whether other small water-soluble solutes such as some guanidino compounds show a kinetic behavior comparable or dissimilar to that of urea. This study included 7 stable conventional hemodialysis patients without residual diuresis undergoing low flux polysulphone dialysis (F8 and F10HPS). Blood samples were collected from the inlet and outlet blood lines before the dialysis session, after 5, 15, 30, 120 minutes, and immediately after discontinuation of the session. Plasma concentrations of urea, creatinine (CTN), creatine (CT), guanidinosuccinic acid (GSA), guanidinoacetic acid (GAA), guanidine (G), and methylguanidine (MG) were used to calculate corresponding dialyzer clearances. A two-pool kinetic model was fitted to the measured plasma concentration profiles, resulting in the calculation of the perfused volume (V1), the total distribution volume (Vtot), and the inter-compartmental clearance (K12); solute generation and ultrafiltration were determined independently. No significant differences were observed between V1 and K12 for urea (6.4 3.3 L and 822 345 mL/min) and for the guanidino compounds. However, with respect to Vtot, GSA was distributed in a smaller volume (30.6 4.2 L) compared to urea (42.7 6.0 L P < 0.001), while CTN, CT, GAA, G, and MG showed significantly larger volumes (54.0 5.9 L, 98.0 52.3 L, 123.8 66.9 L, 89.7 21.4 L, and 102.6 33.9 L, respectively). These differences resulted in markedly divergent effective solute removal: 67% (urea), 58% (CTN), 42% (CT), 76% (GSA), 37% (GAA), 43% (G), and 42% (MG). In conclusion, the kinetics of the guanidino compounds under study are different from that of urea; hence, urea kinetics are not representative for the removal of other uremic solutes, even if they are small and water-soluble like urea.

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Quotidian dialysis Survival in 221 patients treated by short daily hemodialysis for 315 patient years Kjellstrand C.1, Ting G.2, Traeger J.3, Sibai-Galland R.4, Blagg C.R.5, Young B.5 Aksys Ltd, Lincolnshire IL1, El Camino Dialysis, Mountain View, CA2, Claude Bernard University, Lyon, France3, AURAL – Lyon4, France, NW Kidney Center and U of Washington, Seattle , WA5.

Daily hemodialysis greatly improves clinical and biochemical parameters and patient quality of life compared to conventional thrice weekly dialysis. However, mortality statistics are lacking as most centers providing daily dialysis have treated only a small number of relatively selected patients for relatively short observation times. To study patient survival we pooled experience from three sources: 51 French and 128 U.S. patients selected for daily home hemodialysis and 42 U.S. patients selected for short daily center hemodialysis because of many medical complications and cardiovascular instability. Results were compared to age-matched patients from the USRDS 2003 data base. The age of the patients was 51 16 (18–89) years; 29% were female; they had 3.3 1.8 comorbidities (twice that of USRDS patients); 32% had diabetes or hypertension as cause of renal disease (USRDS patients 70%); blood access was 61% fistulae, 25% grafts, and 14% CV-catheters. Mean duration of ESRD treatment at start of short daily hemodialysis was 6 7 years. The observation period was 315 patient years. Patients had been on daily hemodialysis for a mean of 17 18 (0–92) months and 11 patients were observed for more than 5 years. 35 of the 221 patients died (16%); deaths were 111 per 1,000 patient years (53% of expected) and 5-year cumulative survival was 63% compared to 32% for USRDS patients. Five-year survival was 0% in patients with >3 comorbidities, 75% in patients with 3 HR ¼ 6.00 (95% CI 2.2 –16.3). Conclusions: It is difficult to do survival comparisons between patient groups. However, these daily dialysis patients were age-matched with patients from the USRDS database. There were fewer diabetic and hypertensive patients but the comorbidity index was twice that of USRDS patients. Survival, both deaths per 1,000 patient years and cumulative count was approximately twice that reported by the USRDS and strongly suggests superior survival with short daily hemodialysis compared to thrice weekly conventional dialysis.

106 Patient-years experience with the Aksys PHD System for quotidian home hemodialysis Kjellstrand C.M.1, Blagg C.R.2,3, Young B.3, Bower J.4, Twardowski Z.J.5 Aksys Ltd, Lincolnshire IL1, U. Washington, Seattle WA2, Northwest Kidney Centers, Seattle, WA3, Jackson, MS4, U. Missouri, Columbia, MO5.

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The Aksys PHD System, designed to utilize ultrapure dialyzate for quotidian hemodialysis at home, uses mechanical cleaning and hot water sanitization of the blood, dialysate, and water flow-paths from inlet to outlet. Since January 2000, it has been used by 110 US patients and 8 UK patients for a total of 106 patient years and more than 30,000 dialyses runs. Of those treated, 75 patients were male and 43 female; mean age was 52 25 (range 22–82) years; 65% were white, 25% black, and 10% other; mean weight was 78 20 (44–125) kg; the cause of renal failure was primary renal disease (50%), hypertension (24%), diabetes (19%), and other (4%). Dialysis access included fistula (61%), graft (25%), and catheter (14%). Patients had been on ESRD therapy on average of 6 7 (0 –32) years when starting on PHD dialysis. As of August 2004, patients had dialyzed 11 8 (1–52) months on the PHD. Of those, 78 patients remained on the PHD, 12 were transplanted, 10 died, 7 returned to conventional dialysis at the end of the original study for the FDA and 7 for medical or social reasons, 2 returned to quotidian dialysis on other equipment, and 2 stopped during home dialysis training. Patients dialyzed an average of 145 27 min, 5.6 0.6 dialyses/week with a QB of 376 45 ml/min and a QD of 545 170 ml/min. eKt/V was 0.68 0.20 and weekly stdKt/V was 2.61 0.52. Mean dialyser reuse was 17 14 times without significant decline in urea clearance. 23/118 patients (19%) who came to the PHD from quotidian dialysis on other equipment thought the PHD twice as easy to use and experienced only half as many episodes hypotension, cramps, headache, backache, nausea, and arrhythmias (all p < 0.02). They were hospitalized only half as many days on the PHD. Cumulative patient survival was 60% at 4 years, with 94 deaths/1,000 patient years, relative risk 0.56 compared with age-matched patients from the USRDS database. Conclusion: This large clinical experience shows the PHD System is easier to use and delivers smoother dialysis with better cardiovascular stability than conventional dialysis machines. It easily fulfills the DOQI guidelines for adequacy of dialysis, economizes on use of dialyzers, tubing, and dialysate, results in less hospitalization, and appears to result in superior patient survival.

A study of 8 hour long night dialysis with the Aksys PHD dialysis system Kjellstrand C.1, Blagg C.R.2, Ing T.S.3, Young B.2 1Aksys Ltd, Lincolnshire IL, 2NWKC and U. Washington, Seattle, WA, 3Loyola U, Chicago, IL.

The Aksys PHD system is designed for short quotidian dialysis employing a 52-liter batch of ultrapure dialysate and up to 30 in situ hot water reuses of the entire extracorporeal circuit including a 40-liter physical cleaning before each dialysis. Methods: We studied the effect of the 52-liter tank during 108 long 5–8 hour dialysis 3.5–6 times/week in 5 patients and one 50-liter patient simulator for 4 weeks. Phosphate (PO4), beta-2 microglobulin (b-2), urea (BUN), and creatinine



(creat) were measured pre-, during, and post-dialysis 86 times and in total dialysate 74 times during long dialysis. Tank saturation, Kt/V, and monthly chemistries were also measured. Results: Patient weight 76 2 kg, QB 234 23 ml/min, QD 498 13 ml/min. Dialysate was recirculated 4.8 times during 8 hours. Analyte

Short

Pre-BUN Pre-creat Pre-PO4 Pre-b-2

70 18 12 3 5.2 1.5 34.0 5.3

Long dialysis 49 15 10 2 4.1 1.1 27.8 4.5

p 600 ng/ml (therapeutic range 80–400 ng/ml) after 2 hours of hemodialysis and the baclofen level rapidly fell (150 mm Hg (PRE 58.8%, POST 26.5%), blood glycosylated hemoglobin >8% (PRE 33.3%, POST 13.3%), serum cholesterol >200 mg/dL (PRE 48.4%, POST 19.4%). A lower percentage was found in the PRE category for serum phosphorus >5.5 mg/dL (PRE 13.2%, POST 31.6%), while the corresponding percentages for serum albumin 18 years old, with end stage renal disease and on hemodialysis for at least one year were

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included. Those with edema or known ascites were excluded. Weight was measured before and after hemodialysis (HD) using a standard scale and by considering the amount of fluid loss by the hemodialysis machine. Body composition including total body water (TBW) was calculated before and after HD using near infrared interactance (NIR). All measurements were completed during half hour before and after HD. Forty-one patients included: men (n ¼ 26), women (n ¼ 15); median age 58 (range 28–88 years). Twenty-eight were African American and the rest Caucasians. The amount of intravascular fluid taken after HD (assessed by weight reduction) ranged 0–5 L with median 2.2 L. NIR analysis for the same patients at the same time showed different total body water measurements in 91% of cases (P > 0.05). Moreover, NIR analysis showed increase in total body water in 24% of patients even though the hemodialysis machine showed a loss of total body water; median of 1.3 (range: 0–3L). The error in measuring body composition with NIR was both large and varied (random and not systematic error). We conclude that NIR analysis cannot be considered as a reliable method to evaluate body composition, especially total body water, amongst patients with end stage renal disease undergoing hemodialysis.

Biochemical and imaging alterations of renal bone disease in newly detected predialysis and on maintenance dialysis patients Hossain R.M.1, Hoque M.E.2, Rahman H.1, Rashid H.U.1, Iqbal M.3 1 BSM Medical University (BSMMU), Dhaka, Bangladesh, 2Comilla Medical College and 3SSMC and MH, Bangladesh.

Objective: Bone involvement in chronic renal failure is manifested long before the initiation of dialysis and is more prevalent in patients receiving inadequate conservative phase management. This study aimed at identifying the extent of renal bone disease among pre-dialysis and maintenance dialysis patients. Method: Thirty-two patients (gr 1) on maintenance hemodialysis (HD) for variable period of time were compared to twenty newly detected, irregularly treated, (gr 2) pre-dialysis severe renal failure patients for their clinical, biochemical, and imaging features. Result: Mean age of gr 1 and gr 2 patients was 45 14 vs. 34 15 years (p < 0.05). Comparison of blood biochemistry between group 1 and 2 showed serum creatinine 9.9 2.9 vs. 13.4 4.4 mg/dl (P < 0.01), calcium 10 1.4 vs. 7.4 1 mg/dl (p < 0.001); phosphate 4.4 1 vs. 8 2 mg/dl (p < 0.008); ionized calcium 4.7 0.1 vs. 3.9 0.7 mg/dl (p < 0.05); alkaline phosphatase 116 31 vs. 86 31 IU/l (p < 0.05); and iPTH 72 48 vs. 147 92 pg/ml (p < 0.05). Radiological changes present in the two groups were osteopenia-63% vs. 65% (P ¼ NS); trabecular resorption53% vs. 20% (p < 0.05); soft tissue calcification-31% vs. 10% (p < 0.05); bone cyst-16% vs. 25% (P ¼ NS) and subperiosteal bone resorption-16% vs. 20% (P ¼ NS). Tc 99MDP bone scan combined in both groups of patients (n ¼ 52) showed increased uptake in wrist joint (29%), tibia-fibula (25%), costochondral junction, vertebral column (15% each), sternum (13%), radius

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and ulna (10%), and calvaria and mandible (8% each). X-ray finding was positive for bone involvement in 59% cases and Tc 99 scan was positive in 80% (p < 0.05). Association study showed iPTH had a negative correlation with serum calcium (r ¼ 0.5, p < 0.05) and a positive correlation with serum phosphate (r ¼ 0.7, p < 0.05) and alkaline phosphatase (r ¼ 0.9, p < 0.001). Conclusion: It is concluded that predialysis newly detected renal failure patients may present with deranged calcium homeostasis and can manifest high prevalence of bone involvement when compared to maintenance hemodialysis patients.

Vitamin D receptor BsmI and TagI gene polymorphisms in Turkish ESRD population and influences on parathyroid hormone response ¨ zdemir F.N., Tutal E., Sahin F., Akcay A., Haberal M. Sezer S., O Baskent University Hospital, Department of Nephrology, Ankara, Turkey.

Background/Aim: Clinical presentation and complications of end-stage renal disesase (ESRD) patients are under influence of many enviromental and genetic factors. In this study we aimed to define frequencies of BsmI and TagI Vitamin D receptor (VDR) gene polymorphisms and possible influences on clinical presentations in Turkish ESRD population. Methodology and Patients: 186 patients (111 male, 75 female) who are being maintained on hemodialysis were included. Genotyping was performed for the insertion/deletion BsmI (B!b, restriction site, exon VIII!IX), TagI (T!t, 352 exon IX) VDR gene polymorphisms. Last 12 months’ laboratory values (C-reactive protein, intact parathyroid hormone, albumin, calcium, phosphorus, Ca x P product) and clinical findings (vitamin D requirement, body weight) were recorded and analysed retrospectively. Results: Mean age and follow-up period lengths were 42.1 12.6 years and 76.3 43.9 months, respectively. Polymorphism percentages were as follows: BsmI; BB/Bb/bb: 28.9/65.3/5.8%, TagI; TT/ Tt/tt: 36.7/60.5/2.8%, respectively. Further analysis revealed that TT variant of TagI was related with hyperparathyroidism (p < 0.05). Analysis of data after regrouping patients according to iPTH levels (0–249, 250–499, 500 þ pg/mL) and hemodialysis duration (1 dialysis session or shortening a dialysis session>10 min in 1 month, interdialytic weight gain>5.7% of body weight, predialysis serum potassium >6 mEq/L, and phosphate level >7.5 mg/dl. There were 49 noncompliant (age: 46.8 21.8 years, HD duration: 83.9 48.7 months) and 37 compliant (age: 42.8 12.1 years, HD duration: 96.5 45.2 months) patients. QOL was evaluated by short form 36 and depression levels by Beck Depression Inventory. Previous renal transplantation was present in 24.4% and comorbid diseases



in 31.3% of all patients. In depressed patients, 77.8% had comorbid diseases. No difference was found between the groups considering age, gender, dialysis duration, previous transplantation history, and comorbid diseases (p > 0.05). Noncompliant patients had lower QOL (p < 0.04). Noncompliant patients had higher degree of depression (p ¼ 0.01). QOL and Beck scores were negatively correlated (p ¼ 0.001, r ¼ 0.561). Noncompliance to diet and dialysis therapy is associated with depression, which further decreases QOL in renal transplantation waiting list patients. Early diagnosis of depression, is possible by monitoring noncompliance, and therapeutic intervention may benefit during the transplantation-waiting period.

Acute complicating symptoms during hemodialysis sessions have well correlation with deranged blood pressure regulation Iqbal M.M.1, Hossain R.M.2, Rahman H.2, Das S.2, Hossain J.2, Salam A.2, Islam M.N.3, Mohsin M.1 1SSMC and Mitford Hospital, Dhaka, Bangladesh, 2BSM Medical University, and 3BIRDEM Hospital, Dhaka, Bangladesh.

Objective: This observational study was undertaken to evaluate the frequency of acute complications occurring during dialysis sessions and their association with other clinical and biochemical parameters. Method: Forty-six maintenance hemodialysis patients were selected and evaluated. Mean of the weekly evaluations of different parameters over a three-month period is presented here. Result: Age of study subjects was 39 13 years and body mass index (BMI) 21 4 kg/m2. Duration of hemodialysis was 41 29 months. Most of the patients were hypertensive (98%), taking multiple anti-hypertensive drugs. Mean of the blood pressures before and at the end of dialysis sessions over the three month period were: systolic blood pressure (SBP) 159 18 vs. 163 22 (p < 0.05) and diastolic blood pressure (DBP) 92 13 vs. 87 7 mmHg (p < 0.003). Frequency of acute complicating symptoms during dialysis sessions were: headache (75%), rise in blood pressure (73%), leg cramps (67%), vomiting (60%), palpitation (58%), sweating (52%), and hypotension (35%). Raised blood pressure showed a positive correlation with headache (r ¼ 0.50, p < 0.01) and sweating (r ¼ 0.53, p < 0.05). Vomiting and palpitation were more frequent at low post-dialysis blood pressure (vomiting vs. postSBP-r ¼ 0.41, p < 0.05 and palpitation vs. post-DBP-r ¼ 0.48, p < 0.05), and these patients were likely to get inadequate dialysis (hypotension vs. Kt/V-r ¼ 0.63, p < 0.01). Pre and post dialysis weight variation was 53 11 vs. 51 11 kg (p < 0.001), average ultrafiltration during dialysis (UF) 2.39 (0.5–4) liter and single session Kt/V was 0.95 0.38. The rising tendency of post-dialysis blood pressure correlated positively with increasing UF (SBP vs. UF-r ¼ 0.36, p < 0.01 and DBP vs. UF-r ¼ 0.25, p < 0.05). Conclusion: From this study it may be concluded that acute complications during dialysis sessions have a significant correlation with deranged blood pressure

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regulation, and optimum control of blood pressure could provide better dialysis.

Sodium modeling, hypotension, and weight gain in HD Bland A.C.1,2, Pyszka, L.3, Pflederer, B.R.1,2 1RenalCare Associates, Peoria, IL, 2Univ. of IL COM @ Peoria 3RCG, Central IL.

Sodium modeling is a strategy to decrease the incidence of hypotension during hemodialysis. Side effects include increased interdialytic weight gain. By default, all patients at our dialysis center are started on HD with sodium modeling. Purpose: To compare weight gain and blood pressure after discontinuation of sodium modeling. Methods: Ten patients using sodium modeling were changed to a standard sodium bath after a change in attending physician. After IRB approval, we collected and retrospectively reviewed the change in interdialytic weight gains, episodes of hypotension (defined as an episode of hypotension requiring staff intervention), and starting and ending blood pressure. Data from one week prior to Na change (PRE) was compared to one week after Na change (POST) using a paired samples t-test. Results: Data from 4 men and 6 women with a mean age of 65.2 13.7 years was reviewed. ESRD diagnoses included diabetes (n ¼ 4) and hypertension (n ¼ 6). Interdialytic weight gain significantly decreased after discontinuation of sodium modeling (PRE 3.86 kg, POST 3.11 kg, p ¼ 0.004). No significant change in blood pressure at the start (PRE 154/82 POST 156/83, p ¼ 0.745) or end of HD (PRE 123/69, POST 130/67, p ¼ 0.201) was observed. However, the frequency of symptomatic hypotension increased after change to standard sodium bath (PRE ¼ 6%, POST ¼ 27%, p ¼ 0.031). All episodes of hypotension occurred in 3 of the 10 study patients. No patient required cessation of HD or transfer to the emergency department. The degree of weight gain was not correlated with the likelihood of intradialytic hypotension. Conclusion: A change from sodium modeling to standard sodium dialysate lowers interdialytic weight gain but increases the incidence of mild symptomatic hypotension. Further study is needed to determine whether mild hypotension is preferable to increased interdialytic weight gain and to determine the relationship of increased weight gain to complications of volume overload such as LVH and CHF.

Results of improvement in adequacy of intermittent hemodialysis (IHD) in uremic patients Grzegorzewska A.E.1,2, Banachowicz W.2 University of Medical Sciences, Poznan; Center, Rawicz, Poland.

1

Dpt. of Nephrology, 2 International Dialysis

Increasing number of uremic patients, who need IHD, is a great challenge for every society but especially for poor and developing countries. The aim of our study is to look if small (not very

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expensive) increase in IHD adequacy is able to improve standard medical parameters. In 40 patients, treated with IHD for 57.5 (1–185) months, Kt/V was monitored on-line during the middle IHD session in the week, 4 times in each of 6 consecutive months. Measurements of Kt/V based on a conductivity method. In the first month of observation Kt/V was lower (1.09 0.02, p < 0.0009) than in later months, in which Kt/V was ranging from 1.13 0.04 to 1.17 0.01. Blood morphology was estimated every month. At the beginning of study period, after 3 months, and at the end of studies, dry body mass, BMI, the blood pH and serum concentration of calcium, phosphate, intact PTH, total protein, albumin, cholesterol, iron, ferritin, urea, and creatinine were determined. The increase in Kt/V was accompanied by rising values of Hb (99.1 16.6 ! 105.1 12.5 g/l, p ¼ 0.022), Hct (31.6 5.2 ! 33.8 3.6%, p ¼ 0.004), MCV (95.9 7.7 ! 100.7 fl 5.7, p ¼ 0.000), iron (58.2 29.6 ! 73.2 27.8 mg/ dl, p ¼ 0.002), blood pH before (7.26 0.04 ! 7.41 0.04, p ¼ 0.000) and after (7.34 0.05 ! 7.48 0.05, p ¼ 0.000) IHD session as well as by decreasing values of PTH [918 (38 –3500) ! 420 (15–4341) pg/ml, p ¼ 0.036]. Statistically unchanged parameters included dry body mass (70.4 15.6 ! 70.9 16.1 kg), BMI (28.21 6.73 ! 28.23 6.79 kg/m2), serum concentration of total protein (69.1 5.7 ! 70.9 4.8 g/ l), phosphate (5.72 1.50 ! 5.39 2.02 mg/dl), cholesterol (203 49 ! 191 62 mg/dl) and ferritin (740 558 ! 632 346 ng/dl) as well as WBC (8.60 3.89 ! 6.52 1.50 K/ nl) and PLT (251 91 ! 195 60 K/nl). There were correlations between Kt/V and serum concentrations of phosphate (r ¼ 0.370, p ¼ 0.019), PTH (r ¼ 0.314, p ¼ 0.048), ferritin (r ¼ 0.417, p ¼ 0.007), Hb (r ¼ 0.376, p ¼ 0.017), and Hct (r ¼ 0.374, p ¼ 0.017). Our results indicate that even a small increase in IHD adequacy leads to beneficial changes in management of uremic patients (better response on erythropoietin, diminished laboratory features of secondary hyperparathyroidism, better iron utilization). Correlation between Kt/V and examined parameters indicate that higher IHD doses were provided to patients in more advanced uremic state. It may partially explain advantages observed with incremental IHD adequacy.

The relationship of insulin resistance and body fat in chronic kidney disease patients. Satirapoj B., Supasyndh O., Boonyavarakul A., Luesutthiviboon L., Chuvicheer P. Division of Nephrology, Department of Medicine, Phramongkutkloa College of Medicine and Hospital. Bangkok, Thailand.

Background: Insulin resistance has been associated with type 2 diabetes, hypertension, central obesity, and dyslipidemia, all of which are important risk factors for progression of chronic kidney disease (CKD). A greater degree of insulin resistance may predispose to renal injury by worsening renal hemodynamics through the elevation of glomerular filtration fraction. However, there are sparse data on the relationship between insulin resistance, glomerular filtration rate (GFR), and total

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body fat or phase angle in CKD without diabetes. Methods: We examined 84 non-diabetes CKD patients according to the K/DOQI definitions; only 79 patients were enrolled into the study (GFR between 15 and 90 ml/min/1.73 m2). The value of insulin resistance was obtained by homeostasis model assessment (HOMA). Bioelectrical impedance analysis was performed to determine the percentage of total body fat or phase angle. GFR was calculated by the average of creatinine and urea clearances. Results: The correlation analysis showed that HOMA-insulin resistance was positively correlated with phase angle (r ¼ 0.35, P < 0.01), percentage of total body fat (r ¼ 0.27, P < 0.01), body mass index (r ¼ 0.48, P < 0.01) and serum triglyceride levels (r ¼ 0.32, P < 0.01), but not significantly correlated with gender (r ¼ 0.07, P > 0.05), age (r ¼ 0.05, P > 0.05), GFR (r ¼ 0.006, P > 0.05), and mean arterial blood pressure (r ¼ 0.11, P > 0.05). Conclusion: In nondiabetic chronic kidney disease patients, the major risk factor for insulin resistance is the amount of total body fat. The insulin level is not dependent on the GFR in these patients.

External gamma radiation caused by radon in water used for home haemodialysis (HHD) Riitta M.-K., Meeri K., Jyrki H., Tuukka T., Hannu A., Eero H. Helsinki University Hospital, Division of Nephrology and Radiation and Nuclear Safety Authority-STUK, Helsinki, Finland.

Background: Radon is a natural radioactive element found especially in drilled water wells. It may cause problems in HHD. In this study the occurrence and prevention of radiation exposure to radon among HHD patients was examined. Material and methods: Since 1998, 103 patients have been trained for HHD and drilled wells were used in 7 patients. Apart from routine analyses, radon concentration was also determined. Results: High radon concentration was observed in three drilled wells, in one of these 2000 Bq/L. Water was conducted into the HHD-equipment through a charcoal filter and reverse osmosis equipment. Radon concentration was less than 50 Bq/L in the purified water. It was thus considered acceptable for dialysis. As the charcoal filter adsorbs radon, its decay products build up in the filter and emit gamma radiation. Considering that the daily through-put of water is about 375 liters, the estimated dose rate for a radon concentration of 1,000 Bq/L is 0.4 microSv/h at one-meter distance. At this distance the annual dose would be 1.8 mSv, expecting a daily occupancy time of 12 hours. The average background gamma dose rate in Finnish dwellings is 0.1 microSv/h. National dose constraints of 3 mSv/year for adults and 1 mSv/year for children living in HHD-households have been recommended. Conclusions: Waterborne radon must be considered when planning of HHD in households where drilled wells are used. Elevated radon concentration should always be removed from household water. In addition, external gamma radiation from charcoal filters requires appropriate restrictions in order to achieve a safe treatment.



Long slow night hemodialysis and quality of life Hakkarainen P., Kapanen S., Honkanen E., Lo¨flund E. Helsinki. Univ Hospital, Div. of Nephrol, Helsinki, Finland.

Background: Long slow hemodialysis (LS-HD) improves many biochemical parameters compared with conventional HD. However, its influences on quality of life are less well known. Aims: The objective of this study was to examine the quality of life of patients on LS-HD performed overnight compared to the patients on standard hemodialysis. This extends the previous study, conducted in 2001, which examined the LS-HD patients, quality of life. Patients and methods: We sent questionnaires to 12 LS-HD (overnight, treatment time 8 h 3/wk) patients and 15 day HD (4.5 h 3/wk) patients, all being treated using the limited care method. Data was collected using two different structured questionnaires. One was constructed for a previous study (2001) and the other one was a standardized set of questionnaires (RAND-36). Research material was collected from patient documents, such as the essential biochemical parameters, blood pressure, weight gain, and weekly EPO doses were recorded. Ten of the LS-HD patients (83%) and 13/15 (87%) of day HD patients returned the questionnaires. Three day hemodialysis patients returned empty questionnaires, which were disqualified. Results: Based on the medical facts, the results showed that the patients of LS-HD felt better than the patients in another group. Patients on the LS-HD had higher Kt/V (2.623 vs. 1.577) and Hb (118 vs. 111) and lower Pi (1.36 vs. 1.63) and EPO dose (epoietin-beta 2667 ky/week vs. 5833 ky/week; darbepoetin 16 ky/week vs. 37 ky/week). However, their predialysis BP as well as the weight gain between treatments and salt and fluid balances caused problems furthermore. The experiences of the therapy of the LS-HD patients were more positive than of the control group: they felt their medical condition was better than of the patients on day HD. However we didn’t observe significant differences in the replies showing physical or psychosocial conditions between the two groups. Conclusions: The study suggests that when patients can themselves make the choice between treatment modalities, it improves the quality of life of the patients. Control of anemia is improved in LS-HD overnight patients with lower doses of EPO. The LS-HD gives the patients more freedom of diet. However, more attention must be paid to salt and fluid restriction. The LS-HD makes it possible for many patients to work normally.

CQI in the acute dialysis setting Margarita P. Ilumin UC. Davis Health System, Sacramento, CA.

When the acute dialysis program became an in-house operation, the development and implementation of a CQI program was a priority. Quality indicators were identified. Clotting in the dialyzer, treatment delays, and catheter-related infections were tracked. Based on our CQI data, it was clear from the beginning that there was a high incidence of dialyzer clotting, particularly

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on our patients on Extended Daily Dialysis (EDD) who were on heparin-free dialysis. Heparin-free dialysis is prescribed for high bleeding risk patients and for patients with heparin-induced thrombocytopenia. There was a need to explore an effective way to maintain patency and longevity of the extracorporeal circuit as clotting not only results to blood loss but to loss of treatment time, which affects the efficiency and adequacy of the dialysis therapy. Our policy on no-heparin dialysis was modified. Hourly saline flushes were changed to a more aggressive every-15-to-30 minute flushes. In addition, ‘‘heparin rinse’’ or priming the extracorporeal circuits with 5000 units of heparin added to 1-liter bag, except for HIT positive patients, was immediately implemented. After 2 months, clotting in the dialyzer on Extended Daily Dialysis was significantly reduced from 24% to 2%. Conclusion: CQI in the acute dialysis setting is critical for a continuous cycle of evaluating and improving patient outcomes. Through the process of CQI, we were able to identify dialyzer clotting with our EDD as a quality of care problem and implemented a solution that was effective.

Studies of phosphate dynamics during hemodialysis

BW ¼ 212 88 ln (predialysis PO4), (r ¼ 0.39, p < 0.0001). There was no such relationship for Vr for urea or creatinine and no relation between urea and PO4 Vr, (r ¼ 0.07, p ¼ 0.141). In stepwise multiple regression analysis: Mg PO4 removed per week ¼ t 6.5 þ freq 387 þ Uf 140 þ pre-PO4 273 þ PO4 stdKt/V 343 HF 375 1824, (r ¼ 0.73, p < 0.0001). Blood flow(QB) and dialysate flow (QD), urea weekly stdKt/V were not significant variables in the model. Pre-dialysis PO4 ¼ 6.8 Hrs/week 0.07 QB 0.003 þ Uf 0.26. QD, membrane type or dialyses/week did not enter the model. Only patients dialyzing>28 hrs/week could stop phosphate binders within 3 weeks. Conclusions: Phosphate shows a highly variable dynamic during dialysis. Apparently, the body maintains extracellular PO4 concentration by releasing PO4 from unknown compartments when the blood concentration of PO4 decreases. Vr for phosphate thus varies not only from patient to patient but also in a patient, depending on blood concentration of PO4. Kt/V for urea and creatinine are inaccurate in describing PO4 removal. To remove PO4 efficiently it is most important to use long and daily dialysis. QB, QD and membrane type are relatively unimportant in phosphate removal.

Kjellstrand C.M.1, Odar-Cederlof I.2, Ing T.S.3, Blagg C.R4. Aksys Ltd, Lincolnshire IL1, Karolinska Institute Stockholm, Sweden2, Loyola U. Chicago IL 3, NWKC and U. Washington, Seattle, WA.4

Regulation of phosphate (PO4) in hemodialysis patients is very difficult and ideal levels are rarely maintained. A high removal and a normal phosphate level is important, as high and low levels are both associated with morbidity and a very high mortality. We studied phosphate dynamics and its relation to other small ‘‘uremic’’ molecules in 48 patients by measuring pre- and postdialysis levels and all removed phosphate, urea and creatinine (creat) in all dialysate during 455 dialyses done at different frequencies (freq): 3.7 1.2, range 3–6 treatments per week and durations of dialysis (t): mean: 196 95, range 80–560 min and with high (HF) and low flux membranes. Kt/V-PO4, Kt/V-urea and Kt/V-creat, volumes (Vr) for all solutes and their relationships to frequency and duration of dialysis, urea clearance and predialysis phosphate were calculated.

Factor/solute:

PO4

Urea-N

Creatinine

Predialysis mg/dl Postdialysis mg/dl 100 Vr/BW Kt/V Weekly stdKt/V Removed gm/week

5.7 1.9 3.0 1.0 63 78 1.01 0.66 1.75 0.81 3.1 1.3

73 24 33 15 58 24 1.04 0.32 2.12 0.68 56 23

12 3 62 41 15 0.97 0.26 1.96 0.71 6.2 2.5

Vr ¼ removed solute (predialysis minus postdialysis concentration.); BW ¼ body weight. Uf ¼ ultrafiltration. Results: Vr as a percentage of BW for PO4 was dependent on predialysis PO4 and rose steeply as predialysis PO4 decreased: Vr%

98

Pediatrics Access Problems in hemodialysis with a permanent central venous catheter Muscheites J., Drueckler E., Stolpe H.J. and Wigger M. Paediatric Nephrology and Dialysis, University of Rostock, Childrens Hospital, Rostock, Germany.

Hemodialysis is a common treatment of chronic renal failure, also in childhood. Due to the high standard of technique there are only few contraindications for this treatment at present. Limitations are given by the vessel access. But in the last years, hemodialysis has been made practicable by the permanent central venous catheter, however, with more problems. As an example for potential complications in the treatment with the permanent catheter we present an unusual case report about a twenty-oneyear-old girl suffering from chronic renal failure due to reflux nephropathy, Prader-Willi- syndrome, myelonatrophia of undetermined origin with spastic diplegia of the legs, and increasing sphincter ani dysfunction. We started the renal replacement therapy when the girl was 15 years old. It was not possible to create an AV fistula due to very small vessels. Two Gore-Tex 1 implants were clotted in absence of thrombophilia. Afterwards, the hemodialysis was performed by a permanent central venous catheter. The catheter had to be changed 15 times. The reasons for changing the catheter were problems of flow during hemodialysis due to clotting, dislocations, spontaneous removing

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of the catheter by herself, and infections. Altogether a sepsis occurred four times. The first transplantation failed due to a rupture of the transplanted kidney. A second transplantation was not possible because of the high BMI. Intermittently, the girl was treated with peritoneal dialysis (PD) in the hospital, because the PD couldn’t be done at home due to different reasons. Only on weekends could the girl go home. The PD had to be finished after 6 months due to a severe psychotic syndrome. The girl died at age 21, caused by a sepsis following the 15th change of the catheter. A huge problem of frequent catheter changing is the limited availability of vessel accesses – the limits of treatment by hemodialysis.

Kinetics, Dialysis Systems, and Adequacy Copper deficiency: A common cause of erythropoietin (rHuEPO) resistant anemia in children on hemodialysis (HD)? Warady B.A., Nelms C., Jennings J., Johnson S., The Children’s Mercy Hospital, Kansas City, MO.

Copper (CU) deficiency, as reflected by a low serum CU and ceruloplasmin (CER) level, is a rare complication of chronic HD. When present, common clinical manifestations include anemia and neutropenia. Anecdotally, CU deficiency has been linked to the use of sevelamer hydrochloride (SH), a recently introduced phosphate binding agent. The finding of severe CU deficiency and rHuEPOresistant anemia in 3 of our patients (pts) prompted a review of our entire pediatric HD population for the frequency of CU deficiency and its possible relationship to SH. An assessment of serum CU was conducted in 17 pts (male-11; mean age 169.4 þ 49.6 mo) who had received HD for 21.5 þ 33.9 months. All pts received three 4-hour HD sessions weekly with mean single-pool and equilibrated Kt/V values of 2.29 þ 2.5 and 1.56 þ 0.37, respectively. 14 of 17 (82%) pts had low serum CU levels with a mean value of 69.1 þ 38.3 mcG/DL (normal ¼ 85–150 mcG/DL). 9 of 17 (53%) pts had values