Showing papers in "Seminars in Dialysis in 2003"

Cardiovascular disease in chronic renal failure: pathophysiologic aspects.

Abstract: Cardiovascular complications are the leading cause of mortality in patients with end-stage renal disease (ESRD). The excess cardiovascular risk and mortality is already demonstrable in early renal disease and in patients with chronic renal failure (CRF), with the highest relative risk of mortality in the youngest patients. The high risk for cardiovascular disease (CVD) results from the additive effect of multiple factors, including hemodynamic overload and several metabolic and endocrine abnormalities more or less specific to uremia. CVD includes disorders of the heart (left ventricular hypertrophy [LVH], cardiomyopathy) and disorders of the vascular system (atherosclerosis, arteriosclerosis), these two disorders being usually associated and interrelated. LVH is the most frequent cardiac alteration in ESRD, resulting from a combined pressure and volume overload. LVH in general is an ominous prognostic sign and an independent risk factor for arrhythmias, sudden death, heart failure, and myocardial ischemia. Regression of LVH needs a combined intervention to reduce hemodynamic overload and is associated with improved prognosis and survival. Clinical studies have shown that damage of large conduit arteries is a major contributing factor for the high incidence of congestive heart failure (CHF), LVH, ischemic heart disease (IHD), sudden death, cerebrovascular accidents, and peripheral artery diseases. Damage to large conduit arteries is principally related to highly calcified occlusive atherosclerotic lesions and to stiffening of large capacitive arteries. These two complications are independent risk factors for survival, and improvement of arterial stiffness is associated with better prognosis and survival. The present review summarizes the most recent works dealing with the pathophysiology of CVD and some aspects of the therapeutic approach.

Clinical epidemiology of cardiovascular disease in chronic kidney disease prior to dialysis.

Abstract: Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality in patients with end-stage renal disease (ESRD). Both in dialysis and in transplant patients, CVD remains the leading cause of death. There is accumulating evidence that the increase in CVD burden is present in patients prior to dialysis, due to both conventional risk factors as well as those specific to kidney disease. Of importance is that even in patients with mild kidney disease, the risk of cardiovascular events and death is increased relative to patients without evidence of kidney disease. The new classification system proposed by the National Kidney Foundation as part of the Dialysis Outcomes Quality Initiative (DOQI) process describes the five stages of kidney disease, as well as those complications associated with chronic kidney disease (CKD), in particular cardiovascular risk factors and disease. Patients with kidney disease are deemed to be at highest cardiovascular risk. CVD, defined as the presence of either congestive heart failure (CHF), ischemic heart disease (IHD), or left ventricular hypertrophy (LVH), is prevalent in cohorts with established CKD (8-40%). The prevalence of hypertension, a major risk factor for coronary artery disease (CAD) and LVH is high in patients with CKD (87-90%). At least 35% of patients with CKD have evidence of an ischemic event (myocardial infarction or angina) at the time of presentation to a nephrologist. The prevalence of LVH increases at each stage of CKD, reaching 75% at the time of dialysis initiation, and the modifiable risk factors for LVH include anemia and systolic blood pressure, which are also worse at each stage of kidney disease. Even under the care of nephrologists, a change in cardiac status (worsening of heart failure or anginal symptoms) occurs in 20% of patients. The presence of CVD predicts a faster decline of kidney function and the need for dialysis, after controlling for all other factors including glomerular filtration rate (GFR), age, and the presence of LVH. This article describes the new classification system for staging of CKD, defines and describes CVD in CKD, and reviews the evidence and its limitations with respect to the current understanding of CKD and CVD. Specifically, methodologic issues related to survival and referral bias limit our current understanding of the complex interaction of conventional and nonconventional kidney disease-specific risk factors. We identify the importance of well-conducted studies of patient groups with and without CVD, with and without CKD, in order to better understand the complex physiology so that treatment strategies can be appropriately applied.

Hidden sources of phosphorus in the typical American diet: does it matter in nephrology?

Abstract: Elevated serum phosphorus is a major, preventable etiologic factor associated with the increased cardiovascular morbidity and mortality of dialysis patients. An important determinant of serum phosphorus is the dietary intake of this mineral; this makes dietary restriction of phosphorus a cornerstone for the prevention and treatment of hyperphosphatemia. The average daily dietary intake of phosphorus is about 1550 mg for males and 1000 mg for females. In general, foods high in protein are also high in phosphorus. These figures, however, are changing as phosphates are currently being added to a large number of processed foods including meats, cheeses, dressings, beverages, and bakery products. As a result, and depending on the food choices, such additives may increase the phosphorus intake by as a much as 1 g/day. Moreover, nutrient composition tables usually do not include the phosphorus from these additives, resulting in an underestimate of the dietary intake of phosphorus in our patients. Our goal is to convey an understanding of the phosphorus content of the current American diet to better equip nephrologists in their attempt to control hyperphosphatemia.

Tuberculosis and chronic renal disease.

Abstract: There is an increased risk (6.9- to 52.5-fold) of tuberculosis (TB) in patients with chronic renal failure and on dialysis as compared to the general population. The symptomatology in renal patients is often insidious and nonspecific, mimicking uremic symptoms, whereas the localization is often extrapulmonary (most frequently tuberculous lymphadenitis and peritonitis). Tuberculous peritonitis makes up a large part (37%) of the total number of TB cases in continuous ambulatory peritoneal dialysis (CAPD) patients. The prognosis is very much dependent on early diagnosis and treatment. Renal physicians should be aware of the unusual presentation and localization, and include TB in the differential diagnosis of any patient having nonspecific symptoms like anorexia, fever, and weight loss. All efforts should then be made (including invasive investigations) to reach an early diagnosis, a major determinant of the outcome. However, if this is not possible or the result is negative and the diagnosis remains strongly suspected, an empirical trial with anti-TB medication is justified, especially in endemic areas. In view of the increased prevalence of the disease in the dialysis population, TB prophylaxis is recommended in those patients with a positive tuberculin (Mantoux) skin test and radiographs suggestive of old TB.

Clinical epidemiology of cardiac disease in dialysis patients: left ventricular hypertrophy, ischemic heart disease, and cardiac failure.

Abstract: Patients with end-stage renal disease (ESRD) are at extreme cardiovascular risk. At least half of all patients starting dialysis therapy have overt cardiovascular disease (CVD). In addition, recent studies suggest annual incidence rates for new-onset cardiac failure, peripheral vascular disease, ischemic heart disease (IHD), and stroke of approximately 7%, 7%, 5%, and 1%, respectively. High-level exposure to traditional risk factors, such as smoking and dyslipidemia, hemodynamic overload factors, such as anemia and hypertension, and a myriad of metabolic factors related to uremia are all likely to play a role. There has been explosive growth in observational studies and a heartening, if less dramatic, increase in risk factor intervention trials, suggesting that risk factor modification can lead to meaningful benefit.

Thrombosis in end-stage renal disease.

Abstract: Although renal failure has classically been associated with a bleeding tendency, thrombotic events are common among patients with end-stage renal disease (ESRD). A variety of thrombosis-favoring hematologic alterations have been demonstrated in these patients. In addition, "nontraditional" risk factors for thrombosis, such as hyperhomocysteinemia, endothelial dysfunction, inflammation, and malnutrition, are present in a significant proportion of chronic dialysis patients. Hemodialysis (HD) vascular access thrombosis, ischemic heart disease, and renal allograft thrombosis are well-recognized complications in these patients. Deep venous thrombosis and pulmonary embolism are viewed as rare in chronic dialysis patients, but recent studies suggest that this perception should be reconsidered. Several ESRD treatment factors such as recombinant erythropoietin (EPO) administration, dialyzer bioincompatibility, and calcineurin inhibitor administration may have prothrombotic effects. In this article we review the pathogenesis and clinical manifestations of thrombosis in ESRD and evaluate the evidence that chronic renal failure or its management predisposes to thrombotic events.

Pregnancy in dialysis patients: a review of outcomes, complications, and management.

Abstract: Although uncommon, pregnancy occurs in women on chronic dialysis. In 1980 the incidence of pregnancy in women on dialysis was 0.9%. Studies from 1992 to 2003 indicate that pregnancy occurred in 1-7% of women on chronic dialysis. Half of the infants born to women on chronic dialysis survive. Of importance is that "intensive dialysis" of 16-24 hr/week is associated with improved infant survival. In this article, the incidence, duration, fetal and maternal complications, and outcomes of pregnancy in women on chronic dialysis are reviewed. The management of anemia, hypertension, electrolytes, bone minerals, and acid-base parameters in the pregnant dialysis patient is also summarized. Recommendations regarding the dialysis prescription for the pregnant woman on hemodialysis (HD) or peritoneal dialysis (PD) are also made. The complex and precarious condition of the pregnant woman on dialysis requires close collaboration between the patient, nephrologist, dialysis staff, obstetrician, and neonatologist to maximize the chance of a successful pregnancy.

The effect of chronic renal failure on hepatic drug metabolism and drug disposition.

Abstract: There is abundant evidence that chronic renal failure (CRF) and end-stage renal disease (ESRD) alter drug disposition by affecting protein and tissue binding and reducing systemic clearance of renally cleared drugs. What is not fully appreciated is that CRF can significantly reduce nonrenal clearance and alter the bioavailability of drugs predominantly metabolized by the liver. Animal studies in CRF have shown a major down-regulation (40-85%) of hepatic cytochrome P-450 metabolism involving specific isozymes. Phase II reactions such as acetylation and glucuronidation are also involved, with some isozymes showing induction and others inhibition. Hepatic enzymes exhibiting genetic polymorphisms such as N-acetyl-transferase-2 (NAT-2), which is responsible for the rapid and slow acetylator phenotypes, have been shown to be inhibited by ESRD and reversed by transplantation. There is some evidence pointing to the possibility of inhibitory factors circulating in the serum in ESRD patients which may be dialyzable. This review includes all significant animal and clinical studies using the search terms "chronic renal failure,""cytochrome P-450," and "liver metabolism" over the past 10 years obtained from the National Library of Medicine MEDLINE database, including relevant articles back to 1969.

THE CLINICAL EPIDEMIOLOGY OF CARDIOVASCULAR DISEASES IN CHRONIC KIDNEY DISEASE: Traditional Cardiac Risk Factors in Individuals with Chronic Kidney Disease

Abstract: Individuals with chronic kidney disease (CKD) are at increased risk for the development and progression of cardiovascular disease (CVD). The increased risk is due to a higher prevalence of both traditional risk factors as well as nontraditional risk factors. In this review we focus on individuals at all stages of CKD and discuss modifiable traditional risk factors, namely hypertension, dyslipidemia, diabetes mellitus and poor glycemic control, smoking, and physical inactivity. The prevalence of each risk factor and its relationship with CVD is described. Treatment recommendations are provided using evidence available from populations with CKD or evidence extrapolated from the general population when there are insufficient data on individuals with CKD.

Calcium phosphate metabolism and cardiovascular disease in patients with chronic kidney disease.

Abstract: Traditional risk factors for atherosclerotic cardiovascular disease (CVD) do not adequately explain the considerable increase in cardiovascular mortality observed among patients with end-stage renal disease (ESRD): these patients experience mortality rates 10–100 times those without ESRD. Disorders of mineral metabolism, including abnormalities in calcium, phosphorus, parathyroid hormone, and vitamin D, represent cardiovascular risk factors unique to the ESRD population. These disturbances manifest clinically through the promotion of extraskeletal calcification and disorders of bone remodeling, two processes which appear to share a common pathogenesis. This article presents evidence describing the impact of calcification-induced arterial stiffness on cardiovascular outcomes of patients with ESRD, along with data relating altered mineral metabolism to all-cause and cardiovascular mortality. Specific management recommendations include 1) early intervention to prevent the development of overt secondary hyperparathyroidism, 2) a more judicious strategy for vitamin D therapy, and 3) a thoughtful approach to the use of calcium-containing phosphate binders, taking into account the underlying bone remodeling disorder and the presence or absence of extraskeletal calcium accumulation.

Management options for hydrothorax complicating peritoneal dialysis.

Abstract: Hydrothorax as a result of pleuroperitoneal communication occurs in approximately 2% of continuous ambulatory peritoneal dialysis (CAPD) patients. Although our understanding of its mechanisms is incomplete, it is apparent that the key to successful therapy is obliteration of a transdiaphragmatic route of dialysate leakage (pleuroperitoneal communication), possibly coupled with reduction of intra-abdominal pressure. This review corroborated the findings from 10 major population-based case series in which 60 of the 104 cases (58%) were able to resume long-term peritoneal dialysis (PD). Temporary interruption of PD alone was successful in half of them. As compared to this conservative approach, as well as chemical pleurodesis via intercostal chest drain, video-assisted thoracoscopic intervention (including direct pleurodesis and diaphragmatic repair) has shown a promising role. Efficacy of thoracoscopic treatment has been confirmed by several case series from various centers and the demonstration of a success rate in excess of 90%. With accumulating experience using the thoracoscopic technique, it remains to be seen whether this mode of treatment will obviate the traditional closed pleurodesis.

The role of sonography in the planning of arteriovenous fistulas for hemodialysis.

Abstract: Patients presenting for initial access evaluation in contemporary practice are less likely to have arteries and veins suitable for native fistula (AVF) formation in the classic location. Physical examination of the upper extremity alone may be inadequate for selection of arteries and veins that will mature into a functioning AF. The purpose of this paper is to determine how duplex ultrasonography can be used as an effective modality for the preoperative evaluation of vessels before construction of arteriovenous fistula for hemodialysis. The author have used duplex ultrasound (DU) to assess upper-extremity vasculature for planning of dialysis access procedures. Criteria for selection of arteries and veins and a detailed description of DU examination protocol are reviewed. Routine use of upper-extremity DU has identified many patients with veins that are suitable for use and determined arteries with optimal arterial inflow for successful AFV creation.

Interventional Nephrology and Dialysis: Chronic Peritoneal Dialysis Catheters: Overview of Design, Placement, and Removal Procedures

Abstract: The success of chronic peritoneal dialysis (PD) depends to a large extent on the success of the chronic PD access device. For the nephrologist placing and removing PD catheters, or for the nephrologist advising surgeons in this role, this article provides a review of designs of PD catheters and differences in function and complications, methods of insertion of PD catheters and relation to catheter outcomes, techniques for "burying" the external portion of the PD catheter and benefits of this technique, and techniques for removing PD catheters. As nephrologists become more closely involved in the creation, monitoring, and maintenance of access devices for end-stage renal disease (ESRD) patients, the successful function of these devices will increase. Nephrologists should make the critical decisions regarding the choice of access devices and methods for placement as they do for the choice to remove such access devices.

Overcoming barriers to arteriovenous fistula creation and use.

Abstract: National guidelines advocate the placement of arteriovenous fistulas (AVFs) as the preferred vascular access for hemodialysis (HD) patients because of their low complication rate, lower costs, and prolonged patency, once matured. The current Dialysis Outcomes Quality Initiative (DOQI) guidelines aim for an AVF incidence of 50% and a 40% prevalence in the United States. Although patients currently starting dialysis do so at an increasingly older age and with more comorbidity, they should be given every opportunity to receive an AVF. Meeting this challenge is facilitated by a multidisciplinary approach with early referral to the nephrologist in the predialysis period for access planning. Key components of a vascular access program may include the coordination by a dedicated access coordinator and outcome tracking via a prospective database. Preoperative vessel evaluation and careful selection of an appropriate surgical site, along with an experienced surgeon, improve surgical outcomes. Transposed brachiobasilic or other tertiary fistulas should be offered to patients who cannot receive a native radiocephalic or brachiocephalic fistula. The ability to routinely monitor and salvage failing AVFs is important to achieving successful AVF outcomes. Standardized definitions of AVF outcomes are important to allow individual centers and continuous quality assurance (CQA) programs to track and benchmark their outcomes against local and national standards to help them meet recommended targets.

Anticoagulation for intermittent hemodialysis.

Abstract: Hemodialysis is only possible on a routine basis if the tendency for blood to clot when in contact with foreign surfaces is inhibited. Early attempts at extracorporeal circulation used hirudin, extracted from leaches, to prevent coagulation (1, 2). These hirudin preparations appear to have had appreciable toxic side effects and it was not until heparin was adopted as an anticoagulant in the late 1920s that the problem of preventing clotting was removed as a major impediment to the development of hemodialysis (1, 2). Heparin has remained the drug of choice for preventing clotting during hemodialysis; it is relatively inexpensive and most hemodialysis machines are equipped so that heparin can be given with ease. However, an informal survey of chronic hemodialysis units shows no uniform approach to its dosing, in spite of the demonstration that control of anticoagulation can lead to improvements in urea clearance (3) and in dialyzer reuse (4). This article reviews the use of systemic heparinization for anticoagulation in hemodialysis and briefly describes the potential alternatives.

Continuous peritoneal dialysis-associated peritonitis: a review and current concepts.

Abstract: The percentage of end-stage renal disease (ESRD) patients in the United States maintained on continuous peritoneal dialysis (CPD) therapy is decreasing. Complications from CPD therapy, including peritonitis, may be the reason for the decline. Improvements in CPD technology and a better understanding of the risk factors that predispose patients to the development of peritonitis have been responsible for a decline in the rate of peritonitis. Yet peritonitis remains a significant cause of patient morbidity and mortality and the overall outcome of peritonitis is not acceptable. Factors that have limited our ability to lessen the impact of peritonitis include a lack of data on dosing antibiotics in patients on continuous cycling peritoneal dialysis (CCPD) therapy, a lack of knowledge concerning the biology of bacterial biofilm, and the development of resistance to the current prophylactic antibiotic protocols. Further studies are needed concerning the optimal management of the peritoneal catheter and whether it is feasible to resume CPD therapy after catheter removal.

Characteristics and effects of inflammation in end-stage renal disease.

Abstract: Malnutrition and cardiovascular disease are associated with end-stage renal disease (ESRD) and both are closely associated with one another, both in cross-sectional analysis and when the courses of individual patients are followed over time. Inflammation, by suppressing synthesis of albumin, transferrin, and other negative acute-phase proteins and increasing their catabolic rates, either combines with modest malnutrition or mimics malnutrition, resulting in decreased levels of these proteins in dialysis patients. Inflammation also leads to reduced muscle mass by increasing muscle protein catabolism and blocking synthesis of muscle protein. More importantly, inflammation alters plasma protein composition and endothelial structure and function so as to promote vascular disease. Markers of inflammation, C-reactive protein (CRP), and interleukin (IL)-6 powerfully predict death from all causes and from cardiovascular disease in dialysis patients as well as progression of vascular injury. The causes of inflammation are likely multifactorial, including oxidative modification of plasma proteins, interaction of blood with nonbiocompatible membranes and lipopolysaccharides in dialysate, subclinical infection of vascular access materials, oxidative catabolism of endothelium-derived nitric oxide, and other infectious processes. Treatment should be focused on identifying potential causes of inflammation, if obvious, and reduction of other risk factor for cardiovascular disease.

Peritoneal Dialysis Underutilization: The Impact of an Interventional Nephrology Peritoneal Dialysis Access Program

Abstract: Peritoneal dialysis (PD) is an underutilized form of renal replacement therapy. Recent data have emphasized that only 12% of end-stage renal disease (ESRD) patients are initiated on this form of therapy in the United States. Patients requiring PD have most often been referred to general surgeons for catheter placement. This has incurred additional delays in starting treatment and loss of decision-making control by the referring nephrologist. To address this issue, we developed and incorporated our own PD access placement program into the preexisting chronic kidney disease (CKD) education program. To date, 46 patients have undergone 71 procedures. These included 51 (72%) PD catheter insertions, 14 (20%) removals, and 6 (8%) repositioning procedures for poor drainage. PD catheter insertion was performed peritoneoscopically under local anesthesia and a Fogarty catheter was used to reposition a migrated catheter. All of the procedures were performed by nephrologists in a dedicated interventional nephrology (IN) laboratory. All six repositioning procedures failed to restore optimal drainage. Five of these patients had the catheter removed and a new catheter placed during the same procedure. Of these five patients, one had recurrence of poor drainage and opted for hemodialysis (HD). The sixth patient declined reinsertion and chose HD. Of the remaining seven removal procedures, three were due to fungal peritonitis, one due to bowel perforation, one due to severe depression, one due to transplant, and one catheter was removed at the request of the primary physician in a terminally ill patient. Eight of the 51 catheter insertions were during the initial admission of a catastrophic dialysis start. Two of these patients started acute PD and avoided catheter placement for HD. Thirty-seven of 46 patients have a functional PD catheter with a follow-up of 8.6 +/- 0.8 (mean +/- SE) months. During an 18-month period our PD population has increased from 43 to 80 patients. We conclude that a dedicated PD access placement program coupled with a CKD education program can have a dramatic impact on patient choice and PD growth.

Alternative methods of anticoagulation for dialysis-dependent patients with heparin-induced thrombocytopenia.

Abstract: Dialysis patients who are continually exposed to heparin are at risk for heparin-induced thrombocytopenia (HIT). Heparin-induced antibodies have been reported to occur in 0-12% of hemodialysis (HD) patients. The diagnosis or suspicion of HIT in this patient population requires careful confirmation of the diagnosis and substitution of heparin with an alternate anticoagulant for dialysis. Alternate agents such as the direct thrombin inhibitors (hirudin and argatroban) are available, but careful dosing and monitoring of the anticoagulant effect are required. Despite careful dosing, hemorrhagic complications have occurred with these agents. Unfortunately there are limited options for treatment of hemorrhagic complications and no specific antidotes are available for the direct thrombin inhibitors. In this report the currently available alternatives to heparin for dialysis, including dosing and monitoring recommendations, are reviewed.

Infection with antimicrobial-resistant microorganisms in dialysis patients.

Abstract: The prevalence of antimicrobial-resistant microorganisms in various health care settings, including outpatient dialysis facilities, has increased dramatically in the last decade. Antimicrobial use and patient-to-patient transmission of resistant strains are the two main factors that have contributed to this rapid increase. Methicillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative staphylococci are commonly isolated as a cause of hemodialysis (HD) catheter-related bacteremia and peritoneal dialysis (PD)-related catheter infection and peritonitis. The widespread use of vancomycin in dialysis patients is of concern because of an increase in the prevalence of vancomycin-resistant enterococci (VRE) in dialysis patients. Staphylococci with reduced sensitivity to vancomycin have also appeared in dialysis patients. A more recent problem is the appearance of S. aureus isolates with a high degree of resistance to the topical antimicrobial agent mupirocin. This has been seen in PD patients who have received prophylactic application of mupirocin at the peritoneal catheter exit site. Appropriate antimicrobial use will help protect the efficacy of currently used antibiotics, such as vancomycin. Published guidelines for use of vancomycin should be followed. New antimicrobials such as linezolid and quinupristin/dalfopristin have activity against VRE and MRSA, but resistance to these agents has already occurred. Preventing transmission of antimicrobial-resistant microorganisms in health care settings, including outpatient dialysis facilities, is important in limiting the spread of these resistant organisms.

Chronic peritoneal dialysis patients diagnosed with clinical depression: results of pharmacologic therapy.

Abstract: Depression has been documented as the most frequently encountered psychological problem in end-stage renal disease (ESRD) patients and has been correlated with both mortality and morbidity in these patients. Previous work by our group has shown that clinical depression is treatable with psychotropic medications in these patients, but that only a limited number of ESRD patients with depression will successfully complete a course of pharmacologic therapy. From July 1997 to October 2002, all chronic peritoneal dialysis (PD) patients in our facility were encouraged to be screened for depression utilizing the self-administered Beck Depression Inventory (BDI) questionnaire. Based on previous work, a score > or =11 on this questionnaire was used to indicate a possible diagnosis of clinical depression; patients with BDI scores > or =11 were encouraged to complete a more formal evaluation for the presence of clinical depression. A total of 320 BDI questionnaires were completed during the study period: 134 patients. (42%) scored > or =11 on the BDI, 69 of the 134 patients (51%) with BDI scores > or =11 agreed to further evaluation. Sixty of these 69 patients (87%) were diagnosed with clinical depression based on scores > or =18 on the Hamilton Depression Scale and standard Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) criteria. Forty-four patients with clinical depression agreed to pharmacologic treatment. However, only 23 of the 44 patients (52%) successfully completed a 12-week course of drug therapy. Two unit social work reviewers systematically reviewed the records of these 21 patients who did not complete therapy and assessed the reasons for their inability to complete treatment. Reasons identified included eight patients who experienced acute medical problems, three who were active substance abusers, and two who reported medication side effects. The remaining eight patients who did not complete the 12 weeks of therapy were examined by applying the axis 1 and axis 2 DSM-IV criteria. Axis 1 is used to diagnose clinical disorders and axis 2 is used to diagnose personality disorders. While all these patients met the DSM-IV axis 1 criteria for clinical depression, eight of these patients met axis 2 criteria for personality disorders; five patients had borderline personality disorders, one had a narcissistic personality disorder, one had a factitious disorder, and one had features of avoidant personality disorder. While some chronic PD patients can be successfully treated for clinical depression with psychotropic medication prescribed by the dialysis medical team, not all patients will agree to be evaluated for clinical depression and accept pharmacologic treatment. Others cannot or will not complete treatment when additional psychiatric disorders exist. These patients may require additional intervention when diagnosed with clinical depression and a personality disorder. Further trials are warranted.

American Society of Diagnostic and Interventional Nephrology: Section Editor: Stephen Ash: Catheter Management Protocol for Catheter-Related Bacteremia Prophylaxis: CATHETER MANAGEMENT PROTOCOL

Abstract: This study reports a prospective observational study in which an infection prophylaxis protocol based on the National Kidney Foundation's Kidney Disease Outcomes and Quality Initiative (NKF-K/DOQI) guideline 15 describing guidelines for the care of the tunneled dialysis catheter at the time of catheter hook-up for dialysis was used. Catheter-related bacteremia (CRB) incidence data were collected for a 24-month study period and compared to retrospectively collected control data for the immediately preceding 9 months in the same patient population under the same conditions except for the prophylaxis protocol. The incidence of CRB fell from an average level of 6.97 per 1,000 catheter-days during the control period to an average of 1.68 during the study period. This change was statistically significant. Although the lowered incidence required 6 months to reach its maximum, the decreased infection rate was sustained. The average incidence during the last 18 months of the study period was 1.28 per 1,000 catheter-days. Staff compliance with the protocol did require repetitive education and assessment.

Pharmacomechanical thrombolysis of natural vein fistulas: reduced dose of TPA and long-term follow-up.

Abstract: Twenty-five episodes of pharmacomechanical thrombolysis of 20 clotted arteriovenous fistulas (AVFs) are reported. The technique presented utilizes the local instillation of tissue plasminogen activator (TPA) in small doses together with manual maceration to dissolve clot and balloon angioplasty to correct the underlying stenoses. Since the minimum dose of TPA necessary to successfully perform thrombolysis of a natural vein fistula had never been determined, an attempt to use as minimal a dose of TPA as possible was made. Five procedures were performed in fistulas which had previously undergone a thrombolysis procedure with TPA. The procedures were successful in 92% of cases with an average dose of TPA required of 2.3 +/- 0.32 mg/procedure. In addition to the 20 accesses in this article, we offer follow-up life table data on 15 fistulas that were previously reported for a total of 35 accesses salvaged with pharmacomechanical thrombolysis. Primary patency was 11.2 months and secondary patency was 25 months. Fifty-five percent of fistulas required repeat angioplasty procedures at an average of 3.6-month intervals. In addition, more than half of the fistulas that presented with clotting required repeat interventions for continued patency. This report demonstrates the effectiveness of small doses of TPA in successful pharmacomechanical thrombolysis of clotted fistulas.

Managing the complications of long-term tunneled dialysis catheters.

Abstract: The Kidney Disease Outcomes and Quality Initiative (K/DOQI) guidelines call for a significant increase in the use of natural vein fistulas. Long-term tunneled dialysis catheters (LTTDCs) will have an important role in facilitating the maturation of natural vein fistulas. LTTDCs also functions as the access of last resort in patients who refuse or have exhausted other forms of permanent vascular access. This article, which is based on the authors' experience as interventional nephrologists, discusses factors influencing catheter function. In addition, the article reviews common complications associated with dialysis catheter insertion, including immediate, short-term, and long-term complications. The topics reviewed include stenoses, thrombus formation, fibrin sheath formation, infections, and vascular ingrowth. Suggestions for management are also discussed.

The pathophysiology of immune-mediated heparin-induced thrombocytopenia.

Abstract: Heparin-induced thrombocytopenia (HIT) is an important side effect of heparin therapy associated with significant morbidity and mortality if unrecognized. The platelet count typically falls below 150,000/ micro l 5-14 days after heparin is started. Thrombosis is the major clinical complication. The diagnosis is confirmed with a variety of functional and antigenic assays. Heparin binds to PF4, resulting in a conformational change in the molecule that exposes neo-epitopes that act as immunogens. Antibodies form against the heparin-PF4 complex, the major target antigen. The IgG-heparin-PF4 immune complex binds either via its Fab domain to the platelet surface or via its Fc domain to the FcgammaIIA receptor on the surface of the platelet, resulting in further platelet activation. Continued release of PF4 from activated platelets leads to increasing PF4-heparin complex formation, and a self-propagating cycle of platelet consumption and generation of procoagulant platelet-derived microparticles. Other procoagulant effects of the HIT antibody include endothelial cell damage, stimulation of platelet-leukocyte aggregates, and release of tissue factor from monocytes.

THE CLINICAL EPIDEMIOLOGY OF CARDIOVASCULAR DISEASES IN CHRONIC KIDNEY DISEASE: Clinical Epidemiology of Cardiac Disease in Renal Transplant Recipients

Abstract: Cardiovascular disease (CVD) is the major cause of death among renal transplant recipients (RTRs), accounting for 17-50% of deaths. Both cardiomyopathy (congestive heart failure [CHF] and left ventricular hypertrophy [LVH]) and ischemic heart disease (IHD) are important complications of renal transplantation, although the morbid impact of cardiomyopathy has been overlooked until recently. Echocardiographic disorders and clinical CHF occur far more frequently in RTRs than in the general population, suggesting that renal transplantation may be a state of accelerated heart failure. In contrast, the incidence of IHD in RTRs is similar to that in the Framingham cohort. Age, diabetes, and gender remain important markers of risk for both disorders. Smoking, hyperlipidemia, and hypertension appear to be the major reversible risk factors for IHD, while anemia and hypertension are major reversible risk factors for cardiomyopathy. Definitive evidence on optimal intervention is lacking. Clinical trials are needed to define optimum targets for treatment of these risk factors, especially hypertension and anemia.

Dialysis in pregnant women with chronic kidney disease.

Abstract: Pregnancy occurs uncommonly in women with chronic kidney disease (CKD) and fetal outcome tends to be poor, with high rates of prematurity and mortality. Dialysis, by complementing residual renal function, may improve fetal outcome in pregnant women with CKD. Although there are no prospective or randomized trials that examine the relationship between dialysis and fetal outcome, there is evidence that increased solute clearance, by early initiation of or intensification of dialysis, is beneficial for the health of the fetus. Case reports and observational studies from the United States, Belgium, and Saudi Arabia suggest that there is a relationship between successful pregnancy and the amount of dialysis received. Unfortunately, in these reports, measures of residual renal function and dialysis adequacy are lacking or incomplete. Nonetheless, compared to nonpregnant patients with CKD, in pregnant women with CKD it is reasonable to begin dialysis at a higher level of residual renal function in the hope of improving fetal outcome.

THE CLINICAL EPIDEMIOLOGY OF CARDIOVASCULAR DISEASES IN CHRONIC KIDNEY DISEASE: Uremia‐Related Metabolic Cardiac Risk Factors in Chronic Kidney Disease

Abstract: Growing evidence has been gathered over the last 15 years regarding the role of nontraditional or uremia-related risk factors in the pathogenesis of atherosclerosis in subjects with renal failure. Among those factors, dyslipidemia, inflammation, hyperhomocysteinemia, and oxidant stress have been extensively studied. However, the clinical significance of many of these factors remains controversial in light of reported studies. In this article, the existing evidence regarding the role of uremia-related risk factors in the pathogenesis of atherosclerosis is reviewed, with special emphasis on prevalence, cardiac risk, and management in patients with chronic kidney disease (CKD). Consensus treatment recommendations are provided for risk factors for which there is evidence to support preventive or therapeutic interventions.

The implications of water quality in hemodialysis.

Abstract: Water used in dialysis requires additional treatment to minimize patient exposure to potential contaminants that may be present in drinking water. Although standards for the chemical purity of water are in existence and have eliminated many of the problems seen in renal units in the 1970s, some problems remain, and the importance of newer contaminants arising from changes in water treatment at the municipal level are being recognized. Despite this, recent surveys have indicated considerable shortcomings in compliance with chemical standards. The water quality used in the preparation of dialysis fluid also requires minimal bacterial content. Staff working in renal units are frequently unaware of the level of microbiologic contamination in their dialysis fluid arising from the presence of biofilm in the dialysis machines and the water distribution network. Bacterial fragments generated by such biofilms are able to cross the dialysis membrane and stimulate an inflammatory response in the patient. Such inflammation has been implicated in the mortality and morbidity associated with dialysis. The desire to improve treatment outcomes has led to the application of more stringent standards for the microbiologic purity of dialysis fluid and to the introduction of ultraclean dialysis fluid into clinical practice.

THE CLINICAL EPIDEMIOLOGY OF CARDIOVASCULAR DISEASES IN CHRONIC KIDNEY DISEASE: Is Chronic Kidney Disease a Cardiovascular Disease Risk Factor?

Abstract: Cardiovascular disease (CVD) is prevalent in patients with chronic kidney disease (CKD) and may account for 50% of all deaths. The recent Dialysis Outcomes Quality Initiative (DOQI) publication on the evaluation, classification, and stratification of CKD states that a reduced glomerular filtration rate (GFR) identifies individuals at greater risk for CVD and death. This risk is the result of traditional and nontraditional CVD risk factors. However, the relative contribution of these risk factors in the CKD population remains uncertain. Recently interest in kidney disease (reduced GFR) as an independent nontraditional risk factor for CVD has come to the forefront. Studies examining this potential link have included community-based cohort studies, studies in patients with extensive comorbidity, and reports in kidney transplant recipients. Herein, results from these studies are reviewed. The difference between an independent CVD risk factor and a causal CVD risk factor is discussed, with particular emphasis on the temporal association between exposure (GFR) and outcome (CVD and CVD death).