- Email: [email protected]
Vascular access
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EKNOYAN ET AL
near future in light of the many studies underway to address it. REFERENCES
1. Churchill DN, Thorpe KE, Nolph KD, Keshaviah PR, Oreopoulos DG, Page D (CANUSA Study Group): Increased peritoneal membrane transport is associated with decreased patient and technique survival for continuous peritoneal dialysis patients. J Am Soc Neph 9:1285-1292, 1998 2. Clinical Practice Guidelines of the Canadian Society
of Nephrology for Treatment of Patients with Chronic Renal Failure. Chapter 5: Guidelines for adequacy and nutrition in peritoneal dialysis. J Am Soc Nephrol 10:$287-$321, 1999 (suppl 13) 3. Levey AS, Bosch JR Lewis JB, Greene T, Rogers N, Roth D (MDRD Study Group): A more accurate method to estimate glomerular filtration rate from serum creatinine: A new prediction equation. Ann Int Med 130:461-470, 1999 4. Bergstrom J, Heimburger O. Lindholm B: Calculation of the protein equivalent of total nitrogen appearance from urea appearance. Which formulas should be used? Perit Dial Int 18:467-473, 1998
Vascular Access Steve Schwab, MD
HE VASCULAR Access Work Group reviewed all scientific literature published in English from the initial publication of the NKFD O Q I guidelines in 1997 through 1999. Based on review of this literature, a limited number of significant changes were made to the guidelines. In Guideline 3, it was the opinion of the Work Group that the weight of the evidence now supports addition of a statement that a transposed brachiobasilic vein fistula is preferable to a PTFE graft provided surgical expertise to establish a new AV fistula is available and venous anatomy is adequate. One published manuscript shows the significantly better patency with a transposed brachiobasilic vein fistula compared to a PTFE graft, ~as do two manuscripts that are currently in press. In addition, in Guideline 10, it was felt that there is now sufficient evidence to recommend intraaccess flow monitoring as the preferred technique for monitoring AV access. The primary reason for this recommendation is the superiority of intraaccess flow measurements in detecting venous outflow stenosis and in predicting stenosis in native AV fistula. Static venous pressures were considered to be the next most reliable technique, with dynamic venous dialysis pressures still considered to be a satisfactory, but not preferred technique. A table for the interpretation of monthly intra-access flow measurements, as well as a method for monitoring static venous pressure changes, 2~ have been added to the Guideline. New evidence supports the use of antibiotic ointment at the catheter exit site in both cuffed
T
and noncuffed catheters as a mechanism for minimizing exit site infection and catheterrelated bacteremia. 6 Some manufacturers, however, have indicated that ointments that contain glycol constituents should not be used on their polyurethane catheters. A specific recommendation from C. R. Bard, Inc (Pittsburgh, PA), is identified in the guidelines. The Work Group identified an emerging body of evidence that suggests that lytic therapy applied to dialysis catheters, either by slow continuous infusion or by infusion throughout dialysis, has been shown to have significant benefit in the treatment of fibrin sheaths. Preliminary trials using these techniques were indeed promising. However, the withdrawal of Urokinase (Abbott, Abbott Park, IL) from the North American market limited additional studies that may have met the evidentiary basis to have this actually included as a guideline recommendation, v Novel subcutaneous dialysis access ports are also mentioned in the rationale of Guideline 5. Clinical trials regarding their utility are currently underway and may result in the updating of their preferential use. REFERENCES
I. Matseura J, Rosenthal D, Clark M, et al: Transposed basillic vein versus PTFE for brachial axillary arteriovenous fistulae. Am J Surg 176:219-211, 1998 2. Bosman P, Boerboom FT, Stairs H, et al: Pressure or flow recordings for surveillance of hemodialysis grafts. Kidney Int 52:1084-1088, 1998 3. May RE, Himmelfarb J, Ynicesu M, et al: Predicitive
K/DOQI UPDATES
191
measures of vascular access thrombosis: A prospective study. Kidney lnt 52:1656-1662, 1997 4. Neyra R, May R, Ikizler TA, et al: Time-dependent changes in intra-access blood flow is predicitive of subsequent vascular access thrombosis. Kidney Int 54:1714-1719, 1998 5. Besamb A, Ffinak S, Sherman R, et al: Simplified measurement of inua-access pressure. J Am Soc Nephro 9:284-289, 1998
6. Sesso R, Barbosa D, Leme I, et al: Staphylococcus aureus prophylaxis in hemodialysis patients using central venous catheters: Effect of mupirocin ointment. J Am Soc Nepfirol 9:1085-1092, 1998 7. Twardowski Z: High dose intradialytic urokinase to restore the patency of permanent central vein hemodialysis catheters. Am J Kidney Dis 31:841-847, 1998
Treatment of Anemia of Chronic Kidney Disease Joseph W. Eschbach, MD URING THE 3 YEARS since the original 1997 guidelines regarding evidenced-based treatment of the anemia of chronic kidney disease (CKD) were published, over 130 articles have been published on various aspects of anemia as it relates to either erythropoietin (Epoetin) or CKD. The original Anemia Work Group was reconvened to evaluate these articles (one member elected not to continue with the group) and concluded that 37 articles presented new data that supported the original guidelines, or necessitated changes in a guideline, or should result in modification of the original rationale for a Guideline. Changes we have made in the guidelines are discussed below. Anemia causes many physiological abnormalities, which were well described in the original Introduction. New data confirm that intellectual performance decreases in pediatric patients with CKD who are anemic. Perhaps the most significant new recommendation is that anemia should be quantified using hemoglobin rather than hematocrit measurements. The rationale for this change is detailed in Guideline 1. Hematocrit, as measured by an autoanalyzer, is a product of the mean corpuscular volume (MCV) and the total erythrocyte count. Storage of an anticoagulated blood sample at room temperature for more than 8 hours (or for >24 hours when refrigerated), results in erythrocyte swelling and, therefore, in an erroneously high hematocrit. In contrast, the hemoglobin level remains constant under the same conditions. Since many dialysis centers ship blood samples to distant laboratories, under poorly controlled environmental conditions, the risk of erythrocyte swelling is significant. Also, hyperglycemia increases the MCV, resulting in a falsely elevated hematocrit. Automated analyzers also
D
vary a great deal in estimating the number and size of erythrocytes in a blood sample, such variability does not occur for measurement of hemoglobin. For these reasons, hemoglobin is the measurement of choice for all patients. The target hemoglobin/hematocrit (Guideline 4) of l l to 12 g/dL/33% to 36% has been reaffirmed by new data showing that patient survival is better when these values are >11 g/dL or >32% to 33%, respectively. An Italian study 2 showed that survival was better in those maintained at hematocrit values >32% compared with <32%. In the United States, a hematocrit of 33% to 36% was associated with a 10% reduction in the risk of death when compared with patients maintained in a hematocrit range of 30% to 33%. 3 In another study, 1,200 anemic hemodialysis patients with underlying heart disease were randomized to be maintained at either a normal or low hematocrit group. 4 The study was terminated early because there was a detectable, albeit still nonstatistically significant, increased incidence of nonfatal myocardial infarctions or death in those that were randomized to the normal hematocrit group. However, the 200 patients who attained and maintained a normal hematocrit (42% _+ 3%) for at least 6 months had approximately a 15% mortality/year compared with a 40% mortality in patients maintained at a hematocrit of approximately 30%. This study also showed that in those cardiac patients who were randomized to be maintained at a hematocrit of 30% _+ 3%, survival improved in those who achieved higher hematocrit levels. Additional studies that have been reported also confirm the value of maintaining hemoglobin values -> 11 and hematocrit ->33%. Hospitalization rates were lower when the hematocrit
EKNOYAN ET AL
near future in light of the many studies underway to address it. REFERENCES
1. Churchill DN, Thorpe KE, Nolph KD, Keshaviah PR, Oreopoulos DG, Page D (CANUSA Study Group): Increased peritoneal membrane transport is associated with decreased patient and technique survival for continuous peritoneal dialysis patients. J Am Soc Neph 9:1285-1292, 1998 2. Clinical Practice Guidelines of the Canadian Society
of Nephrology for Treatment of Patients with Chronic Renal Failure. Chapter 5: Guidelines for adequacy and nutrition in peritoneal dialysis. J Am Soc Nephrol 10:$287-$321, 1999 (suppl 13) 3. Levey AS, Bosch JR Lewis JB, Greene T, Rogers N, Roth D (MDRD Study Group): A more accurate method to estimate glomerular filtration rate from serum creatinine: A new prediction equation. Ann Int Med 130:461-470, 1999 4. Bergstrom J, Heimburger O. Lindholm B: Calculation of the protein equivalent of total nitrogen appearance from urea appearance. Which formulas should be used? Perit Dial Int 18:467-473, 1998
Vascular Access Steve Schwab, MD
HE VASCULAR Access Work Group reviewed all scientific literature published in English from the initial publication of the NKFD O Q I guidelines in 1997 through 1999. Based on review of this literature, a limited number of significant changes were made to the guidelines. In Guideline 3, it was the opinion of the Work Group that the weight of the evidence now supports addition of a statement that a transposed brachiobasilic vein fistula is preferable to a PTFE graft provided surgical expertise to establish a new AV fistula is available and venous anatomy is adequate. One published manuscript shows the significantly better patency with a transposed brachiobasilic vein fistula compared to a PTFE graft, ~as do two manuscripts that are currently in press. In addition, in Guideline 10, it was felt that there is now sufficient evidence to recommend intraaccess flow monitoring as the preferred technique for monitoring AV access. The primary reason for this recommendation is the superiority of intraaccess flow measurements in detecting venous outflow stenosis and in predicting stenosis in native AV fistula. Static venous pressures were considered to be the next most reliable technique, with dynamic venous dialysis pressures still considered to be a satisfactory, but not preferred technique. A table for the interpretation of monthly intra-access flow measurements, as well as a method for monitoring static venous pressure changes, 2~ have been added to the Guideline. New evidence supports the use of antibiotic ointment at the catheter exit site in both cuffed
T
and noncuffed catheters as a mechanism for minimizing exit site infection and catheterrelated bacteremia. 6 Some manufacturers, however, have indicated that ointments that contain glycol constituents should not be used on their polyurethane catheters. A specific recommendation from C. R. Bard, Inc (Pittsburgh, PA), is identified in the guidelines. The Work Group identified an emerging body of evidence that suggests that lytic therapy applied to dialysis catheters, either by slow continuous infusion or by infusion throughout dialysis, has been shown to have significant benefit in the treatment of fibrin sheaths. Preliminary trials using these techniques were indeed promising. However, the withdrawal of Urokinase (Abbott, Abbott Park, IL) from the North American market limited additional studies that may have met the evidentiary basis to have this actually included as a guideline recommendation, v Novel subcutaneous dialysis access ports are also mentioned in the rationale of Guideline 5. Clinical trials regarding their utility are currently underway and may result in the updating of their preferential use. REFERENCES
I. Matseura J, Rosenthal D, Clark M, et al: Transposed basillic vein versus PTFE for brachial axillary arteriovenous fistulae. Am J Surg 176:219-211, 1998 2. Bosman P, Boerboom FT, Stairs H, et al: Pressure or flow recordings for surveillance of hemodialysis grafts. Kidney Int 52:1084-1088, 1998 3. May RE, Himmelfarb J, Ynicesu M, et al: Predicitive
K/DOQI UPDATES
191
measures of vascular access thrombosis: A prospective study. Kidney lnt 52:1656-1662, 1997 4. Neyra R, May R, Ikizler TA, et al: Time-dependent changes in intra-access blood flow is predicitive of subsequent vascular access thrombosis. Kidney Int 54:1714-1719, 1998 5. Besamb A, Ffinak S, Sherman R, et al: Simplified measurement of inua-access pressure. J Am Soc Nephro 9:284-289, 1998
6. Sesso R, Barbosa D, Leme I, et al: Staphylococcus aureus prophylaxis in hemodialysis patients using central venous catheters: Effect of mupirocin ointment. J Am Soc Nepfirol 9:1085-1092, 1998 7. Twardowski Z: High dose intradialytic urokinase to restore the patency of permanent central vein hemodialysis catheters. Am J Kidney Dis 31:841-847, 1998
Treatment of Anemia of Chronic Kidney Disease Joseph W. Eschbach, MD URING THE 3 YEARS since the original 1997 guidelines regarding evidenced-based treatment of the anemia of chronic kidney disease (CKD) were published, over 130 articles have been published on various aspects of anemia as it relates to either erythropoietin (Epoetin) or CKD. The original Anemia Work Group was reconvened to evaluate these articles (one member elected not to continue with the group) and concluded that 37 articles presented new data that supported the original guidelines, or necessitated changes in a guideline, or should result in modification of the original rationale for a Guideline. Changes we have made in the guidelines are discussed below. Anemia causes many physiological abnormalities, which were well described in the original Introduction. New data confirm that intellectual performance decreases in pediatric patients with CKD who are anemic. Perhaps the most significant new recommendation is that anemia should be quantified using hemoglobin rather than hematocrit measurements. The rationale for this change is detailed in Guideline 1. Hematocrit, as measured by an autoanalyzer, is a product of the mean corpuscular volume (MCV) and the total erythrocyte count. Storage of an anticoagulated blood sample at room temperature for more than 8 hours (or for >24 hours when refrigerated), results in erythrocyte swelling and, therefore, in an erroneously high hematocrit. In contrast, the hemoglobin level remains constant under the same conditions. Since many dialysis centers ship blood samples to distant laboratories, under poorly controlled environmental conditions, the risk of erythrocyte swelling is significant. Also, hyperglycemia increases the MCV, resulting in a falsely elevated hematocrit. Automated analyzers also
D
vary a great deal in estimating the number and size of erythrocytes in a blood sample, such variability does not occur for measurement of hemoglobin. For these reasons, hemoglobin is the measurement of choice for all patients. The target hemoglobin/hematocrit (Guideline 4) of l l to 12 g/dL/33% to 36% has been reaffirmed by new data showing that patient survival is better when these values are >11 g/dL or >32% to 33%, respectively. An Italian study 2 showed that survival was better in those maintained at hematocrit values >32% compared with <32%. In the United States, a hematocrit of 33% to 36% was associated with a 10% reduction in the risk of death when compared with patients maintained in a hematocrit range of 30% to 33%. 3 In another study, 1,200 anemic hemodialysis patients with underlying heart disease were randomized to be maintained at either a normal or low hematocrit group. 4 The study was terminated early because there was a detectable, albeit still nonstatistically significant, increased incidence of nonfatal myocardial infarctions or death in those that were randomized to the normal hematocrit group. However, the 200 patients who attained and maintained a normal hematocrit (42% _+ 3%) for at least 6 months had approximately a 15% mortality/year compared with a 40% mortality in patients maintained at a hematocrit of approximately 30%. This study also showed that in those cardiac patients who were randomized to be maintained at a hematocrit of 30% _+ 3%, survival improved in those who achieved higher hematocrit levels. Additional studies that have been reported also confirm the value of maintaining hemoglobin values -> 11 and hematocrit ->33%. Hospitalization rates were lower when the hematocrit