Direct oral anticoagulant medications in calciphylaxis

BACKGROUND

Recent studies suggest that calciphylaxis is a thrombotic condition in which arteriolar thrombosis leads to painful skin infarcts and consequent morbidity and mortality. Paradoxically, warfarin is implicated as a risk factor for calciphylaxis. Our objective is to report the use of oral direct thrombin and factor Xa inhibitors (termed direct oral anticoagulants [DOACs]) in patients with calciphylaxis.

METHODS

We retrospectively reviewed records of 16 patients with calciphylaxis who received concomitant administration of novel anticoagulants. Patient data, including demographics, comorbidities, other treatments, and adverse events, were abstracted from the health records.

RESULTS

Eleven patients (69%) had chronic kidney disease (stage ≥3A), and eight (50%) received dialysis. Apixaban was the most frequently used agent (n = 11 [69%]). Dabigatran (n = 4 [25%]) and rivaroxaban (n = 2 [13%]) were reserved for patients with mild renal impairment (stage ≤2). One clinically relevant but nonmajor bleeding event occurred. There were no major bleeding events. Nine patients (56%) were alive at last follow-up, and five (31%) had complete resolution of their calciphylaxis (mean follow-up, 523 days; range, 26-1884 days).

CONCLUSION

DOACs were safe and well tolerated in patients with calciphylaxis, in this initial experience. Several patients had improvement or resolution of calciphylaxis in response to therapy that included DOACs. The degree of renal impairment should guide DOAC choice. Randomized trials are required to determine treatment efficacy.

National Impact of Maintenance Dialysis or Renal Transplantation on Outcomes Following ST Elevation Myocardial Infarction

BACKGROUND

Though cardiovascular disease is an important cause of mortality in patients with end-stage renal disease, epidemiology of ST-elevation myocardial infarction (STEMI) is less well described in this population.

METHODS

This study included STEMI hospitalizations in patients aged ≥20 using Nationwide Inpatient Sample Database from 2006 to 2010. Primary outcomes were incidence and trends of STEMI hospitalizations based on renal function status. We also looked at utilization of revascularization procedures, all-cause-hospital mortality and predictors of mortality.

RESULTS

Of the estimated 882,447 STEMI hospitalizations, 11,383 were on maintenance dialysis and 1,076 had renal transplants. The incidence of STEMI was over 7 times in patients on maintenance dialysis and 1.73 times in renal transplant recipients compared to the general population. This incidence has however declined in those on maintenance dialysis (p for trend <0.001) to a greater extent than the general population and patients with renal transplant. Utilization of revascularization procedures was lowest in patients on maintenance dialysis (51.6 vs. 73.3% in renal transplant recipients and 77.0% in general population; p < 0.001) and mortality was highest (21.6 vs. 10.9 vs. 6.8%; p < 0.001). Being on maintenance dialysis or having a renal transplant were both independent predictors of mortality in patients hospitalized with STEMI. There was a differential effect of cardiac catheterization on odds of mortality with lesser impact in patients on maintenance dialysis.

CONCLUSIONS

STEMI hospitalizations are more common in patients on maintenance dialysis and with renal transplants. The utilization of revascularizations procedures remains low and mortality high in these patients.

Survival, Risk Factors, and Effect of Treatment in 101 Patients With Calciphylaxis

OBJECTIVE

To report on the survival and the associations of treatments upon survival of patients with calciphylaxis seen at a single center.

PATIENTS AND METHODS

Using the International Classification of Diseases, Ninth Revision diagnosis code of 275.49 and the keyword "calciphylaxis" in the dismissal narrative, we retrospectively identified 101 patients with calciphylaxis seen at our institution between January 1, 1999, through September 20, 2014, using a predefined, consensus-developed classification scheme.

RESULTS

The average age of patients was 60 years: 81 (80.2%) were women; 68 (68.0%) were obese; 19 (18.8%) had stage 0 to 2 chronic kidney disease (CKD), 19 (18.9%) had stage 3 or 4 CKD; 63 (62.4%) had stage 5 or 5D (dialysis) CKD. Seventy-five patients died during follow-up. Six-month survival was 57%. Lack of surgical debridement was associated with insignificantly lower 6-month survival (hazard ratio [HR]=1.99; 95% CI, 0.96-4.15; P=.07) and significantly poorer survival for the entire duration of follow-up (HR=1.98; 95% CI, 1.15-3.41; P=.01), which was most pronounced in stage 5 or 5D CKD (HR=1.91; 95% CI, 1.03-3.56; P=.04). Among patients with stage 5/5D CKD, subtotal parathyroidectomy (performed only in patients with hyperparathyroidism) was associated with better 6-month (HR=0.12; 95% CI, 0.02-0.90; P=.04) and overall survival (HR= 0.37; 95% CI, 0.15-0.87; P=.02).

CONCLUSION

Calciphylaxis is associated with a high mortality rate. Significantly effective treatments included surgical debridement and subtotal parathyroidectomy in patients with stage 5/5D CKD with hyperparathyroidism. Treatments with tissue-plasminogen activator, sodium thiosulfate, and hyperbaric oxygen therapy were not associated with higher mortality.

Calciphylaxis: A Disease of Pannicular Thrombosis

OBJECTIVE

To identify coagulation risk factors in patients with calciphylaxis and the relationship between anticoagulation use and overall survival.

PATIENTS AND METHODS

Study subjects were 101 patients with calciphylaxis seen at Mayo Clinic from 1999 to September 2014. Data including thrombophilia profiles were extracted from the medical records of each patient. Survival status was determined using patient registration data and the Social Security Death Index. Survival was estimated using the Kaplan-Meier method, and associations were evaluated using Cox proportional hazards models.

RESULTS

Sixty-four of the 101 patients underwent thrombophilia testing. Of these, a complete test panel was performed in 55 and a partial panel in 9. Severe thrombophilias observed in 60% (33 of 55) of the patients included antiphospholipid antibody syndrome protein C, protein S, or antithrombin deficiencies or combined thrombophilias. Of the 55 patients, severe thrombophilia (85%, 23 of 27) was noted in patients who were not on warfarin at the time of testing (27). Nonsevere thrombophilias included heterozygous factor V Leiden (n=2) and plasminogen deficiency (n=1). For the comparison of survival, patients were divided into 3 treatment categories: Warfarin (n=63), other anticoagulants (n=20), and no anticoagulants (n=18). There was no statistically significant survival difference between treatment groups.

CONCLUSION

Laboratory testing reveals a strikingly high prevalence of severe thrombophilias in patients with calciphylaxis, underscoring the importance of congenital and acquired thrombotic propensity potentially contributing to the pathogenesis of this disease. These findings may have therapeutic implications; however, to date, survival differences did not vary by therapeutic choice.

Total Red Blood Cell Transfusions for Chronic Hemodialysis Patients in a Single Center, 2009-2013

BACKGROUND

Anemia management in chronic hemodialysis (HD) has been affected by the implementation of the prospective payment system (PPS) and changes in clinical guidelines. These factors could impact red blood cell (RBC) transfusion in HD patients. Our distinctive care system contains complete records for all RBC transfusions among our HD patients.

AIMS

To determine RBC transfusions in patients with prevalent chronic HD, site of administration (inpatient or outpatient), and ordering physician specialty for inpatients; compare pre- and post-PPS RBC transfusions; and compare RBC transfusions during changes in desired outpatient hemoglobin (Hb) range for patients with chronic HD.

METHODS

Retrospective analysis of medical and blood bank records for patients with prevalent chronic HD July 2009 through June 2013.

RESULTS

In total, 310-356 patients were studied. Mean (SD) units of RBCs per 100 patients per month for the study's 48 months were outpatient, 2.6 (1.5), and inpatient, 9.4 (4.6). Outpatient pre-PPS RBC units transfused were 2.1 (0.6) vs. post-PPS of 2.6 (1.5; p = 0.22, t test); for inpatients pre-PPS, 7.9 (4.5) RBC units per month vs. post-PPS, 11.5 (5.1; p = 0.11, t test). Inpatient RBC transfusions accounted for 75.2% (14.2%) of all RBC transfusions; 67.3% (16.3%) of inpatient transfusions were ordered by nonnephrologists. Changes in desired Hb range for outpatient HD patients did not lead to changes in RBC transfusions.

CONCLUSIONS

No changes in RBC transfusions occurred among our patients with chronic HD with PPS implementation and in desired Hb range during the study period. Most transfusions were given in inpatient settings by nonnephrologists.

Predictors of outpatient kidney function recovery among patients who initiate hemodialysis in the hospital

BACKGROUND

Recent policy clarifications by the Centers for Medicare & Medicaid Services have changed access to outpatient dialysis care at end-stage renal disease (ESRD) facilities for individuals with acute kidney injury in the United States. Tools to predict "ESRD" and "acute" status in terms of kidney function recovery among patients who previously initiated dialysis therapy in the hospital could help inform patient management decisions.

STUDY DESIGN

Historical cohort study.

SETTING & PARTICIPANTS

Incident hemodialysis patients in the Mayo Clinic Health System who initiated in-hospital renal replacement therapy (RRT) and continued outpatient dialysis following hospital dismissal (2006 through 2009).

PREDICTOR

Baseline estimated glomerular filtration rate (eGFR), acute tubular necrosis from sepsis or surgery, heart failure, intensive care unit, and dialysis access.

OUTCOMES

Kidney function recovery defined as sufficient kidney function for outpatient hemodialysis therapy discontinuation.

RESULTS

Cohort consisted of 281 patients with a mean age of 64 years, 63% men, 45% with heart failure, and baseline eGFR≥30mL/min/1.73m(2) in 46%. During a median of 8 months, 52 (19%) recovered, most (94%) within 6 months. Higher baseline eGFR (HR per 10-mL/min/1.73m(2) increase eGFR, 1.27; 95% CI, 1.16-1.39; P<0.001), acute tubular necrosis from sepsis or surgery (HR, 3.34; 95% CI, 1.83-6.24; P<0.001), and heart failure (HR, 0.40; 95% CI, 0.19-0.78, P=0.007) were independent predictors of recovery within 6 months, whereas first RRT in the intensive care unit and catheter dialysis access were not. There was a positive interaction between absence of heart failure and eGFR≥30mL/min/1.73m(2) for predicting kidney function recovery (P<0.001).

LIMITATIONS

Sample size.

CONCLUSIONS

Kidney function recovery in the outpatient hemodialysis unit following in-hospital RRT initiation is not rare. As expected, higher baseline eGFR is an important determinant of recovery. However, patients with heart failure are less likely to recover even with a higher baseline eGFR. Consideration of these factors at hospital discharge informs decisions on ESRD status designation and long-term hemodialysis care.

Risk factors for hospitalization among older, incident haemodialysis patients

AIMS

The number of elderly persons with end-stage renal disease is increasing with many requiring hospitalizations. This study examines the causes and predictors of hospitalization in older haemodialysis patients.

METHODS

We reviewed hospitalizations of older (≥65 years) incident chronic haemodialysis patients initiating therapy between 1 January 2007 and 31 December 2009 under the care of a single Midwestern United States dialysis provider.

RESULTS

Of 125 patients, the mean age was 76 ± 7 years and 72% were male. At first dialysis, 68% used a central venous catheter (CVC) and 51% were in the hospital. Mean follow-up was 1.8 ± 1.0 years. At least one hospitalization occurred in 89 (71%) patients and half of all patients were hospitalized once within the first 223 days. Total hospital admission rate was 1.48 per patient year with hospital days totalling 8.54 days per patient year. The three most common reasons for first admission were cardiac (33%), infection (18%) and gastrointestinal (12%). Predictors of future hospitalization included the first dialysis occurring in hospital (hazard ratios (HR) 2.1, 95% CI 1.4-3.3, P = 0.0005) and the use of a CVC at first haemodialysis (HR 2.6, CI 1.6-4.4, P < 0.0001).

CONCLUSION

Hospitalizations are common in older incident haemodialysis patients. Access preparation and overall burden of illness leading to the initial hospitalization appear to play a role. Identification of additional factors associated with hospitalization will allow for focused interventions to reduce hospitalization rates and increase the value of care.

Biomedical system dynamics to improve anemia control with darbepoetin alfa in long-term hemodialysis patients

OBJECTIVE

To determine the value of a biomedical system dynamics (BMSD) approach for optimization of anemia management in long-term hemodialysis patients because elevated hemoglobin levels and high doses of erythropoiesis-stimulating agents (ESAs) may negatively affect survival in this population.

PATIENTS AND METHODS

A model of erythropoiesis and its response to ESAs on the basis of a BMSD method (Mayo Clinic Anemia Management System [MCAMS]) was developed. Thereafter, an open-label, prospective, nonrandomized practice quality improvement project was performed with retrospective analysis in 8 community-based outpatient hemodialysis facilities. All prevalent hemodialysis patients seen from January 1, 2007, through December 31, 2010 (300-342 patients per month), were included with darbepoetin as the ESA. The primary outcome was the percentage of patients who attained the desired hemoglobin level. Secondary outcome measures included the percentage of patients with hemoglobin values above the desired range and mean dose of darbepoetin used.

RESULTS

The 3 treatment periods were (1) standard ESA protocol in 2007, (2) transition to the MCAMS (2008 to June 2009), and (3) stability period with the MCAMS used in all hemodialysis facilities (2009 to 2010). In the first 6 months of 2007, 69% of patients were in the desired range and 26% were above the range. In comparison, during the first 5 months of 2010, 83% were in and 6% were above the range (P<.001). The mean monthly darbepoetin dose per patient decreased from 304 μg in 2007 to 173 μg by the second half of 2009 (P<.001).

CONCLUSION

With the introduction of the MCAMS, more patients had hemoglobin levels in the desired range and fewer patients exceeded the target range, with a concomitant 40% reduction in darbepoetin use.

Effects of ozone in normal human epidermal keratinocytes

Ozone is a tropospheric pollutant that can form at ground level as a result of an interaction between sunlight and hydrocarbon engine emissions. As ozone is an extremely oxidative reaction product, epidermal cells are in the outer layer of defense against ozone. We exposed normal human epidermal keratinocytes (NHEK) to concentrations of ozone that have been measured in cities and assayed for its effects. Hydrogen peroxide and IL-1α levels both increased while ATP levels decreased. We found a decrease in the NAD-dependent histone deacetylase, sirtuin 3. Lastly, we found that ozone increased DNA damage as evaluated by Comet assay. Taken together, our results show increased damage to NHEK that will ultimately impair normal cellular function as a result of an environmentally relevant ozone exposure.

Development of reduced kidney function in rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) is associated with a variety of kidney disorders. However, it is unclear whether the development of reduced kidney function is higher in patients with RA compared to the general population.

STUDY DESIGN

Retrospective review.

SETTING & PARTICIPANTS

Incident adult-onset RA cases (813) and a comparison cohort of non-RA individuals (813) in Olmsted County, MN, in 1980-2007.

PREDICTOR

Baseline demographic and clinical variables.

OUTCOMES

Reduced kidney function: (1) estimated glomerular filtration rate (eGFR)<60mL/min/1.73m(2) and (2) eGFR<45mL/min/1.73m(2) on 2 consecutive occasions at least 90 days apart; cardiovascular disease (CVD); and death.

MEASUREMENTS

The cumulative incidence of reduced kidney function was estimated adjusting for the competing risk of death.

RESULTS

Of 813 patients with RA and 813 non-RA individuals, mean age was 56±16 (SD) years, 68% were women, and 9% had reduced kidney function at baseline. The 20-year cumulative incidence of reduced kidney function was higher in patients with RA compared with non-RA participants for eGFR < 60mL/min/1.73m(2) (25% vs 20%; P=0.03), but not eGFR<45mL/min/1.73m(2) (9% vs 10%; P=0.8). The presence of CVD at baseline (HR, 1.77; 95% CI, 1.14-2.73; P=0.01) and elevated erythrocyte sedimentation rate in patients with RA (HR per 10-mm/h increase, 1.08; 95% CI, 1.00-1.16; P=0.04) was associated with increased risk of eGFR<60mL/min/1.73m(2). eGFR<60mL/min/1.73m(2) was not associated with increased risk of CVD development in patients with RA (HR, 0.99; 95% CI, 0.63-1.57; P=0.9), however, a greater reduction in GFR (eGFR<45mL/min/1.73m(2)) was associated with increased risk of CVD (HR, 1.93; CI, 1.04-3.58; P=0.04).

LIMITATIONS

Reduced kidney function was defined by estimating equations for kidney function. We are limited to deriving associations from our findings.

CONCLUSIONS

Patients with RA were more likely to develop reduced kidney function over time. CVD and associated factors appear to play a role. The presence of RA in individuals with reduced kidney function may lead to an increase in morbidity from CVD development, for which awareness may provide a means for optimizing care.

Outcomes of arteriovenous fistula creation after the Fistula First Initiative

BACKGROUND AND OBJECTIVES

The arteriovenous fistula (AVF) is the preferred hemodialysis access, but AVF-failure rate is high, and complications from AVF placement are rarely reported. There is no clear consensus on predictors of AVF patency. This study determined AVF outcomes and patency predictors at Mayo Clinic Rochester following the Fistula First Initiative.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A retrospective cohort study of AVFs placed at Mayo Clinic from January 2006 through December 2008 was performed. The AVF placement-associated primary and secondary failure rates, complications, interventions, and hospitalizations were examined. Kaplan-Meier survival curves and Cox proportional hazard models were used to determine primary and secondary patency and associated predictors.

RESULTS

During this time frame, 317 AVFs were placed in 293 individual patients. The primary failure rate was 37.1% after excluding patients not initiated on hemodialysis during follow-up (n = 38) or those with indeterminate outcome (37 lost to follow-up; six died; two transplanted). Of usable AVFs, 11.4% later failed. AVF creation incurred complications and hospitalization in 21.2% and 12.3% of patients, respectively. The risk for reduced primary patency was increased by diabetes (HR, 1.54; 95% CI, 1.14 to 2.07); the risk for reduced primary and secondary patency was decreased with larger arteries (HR, 0.83; 95% CI, 0.73 to 0.94; and HR, 0.69; 95% CI, 0.56 to 0.84, respectively).

CONCLUSIONS

Primary failure remains a major issue in the post-Fistula First era. Complications from AVF placement must be considered when planning AVF placement. Our data demonstrate that artery size is the main predictor of AVF patency.

Use of renal function measurements for assessing fracture risk in postmenopausal women

OBJECTIVE

To determine whether factors associated with moderate chronic kidney disease can be used to independently predict fracture risk in postmenopausal white women by analyzing the effect of adding renal function measurements to traditional risk factors (eg, age, body weight, bone mineral density) for fracture risk assessment.

PARTICIPANTS AND METHODS

In a prospective, population-based cohort study, postmenopausal women residing in Rochester, MN, with baseline measurements of bone mineral density and renal function were followed up for as long as 25 years for occurrence of fractures. Participants were enrolled in 1980-1984 or 1991-1993, and outcomes were analyzed in 2007. Standardized incidence ratios were used to compare the number of observed fractures with the number of predicted fractures, and potential risk factors were evaluated with Andersen-Gill time-to-fracture regression models.

RESULTS

During 5948 person-years of follow-up of 427 women, 254 women (59.5%) experienced a total of 563 fractures, 394 (70.0%) of which resulted from moderate trauma. Excluding incidentally diagnosed fractures, the 186 clinically diagnosed fractures were statistically undifferentiated from the 195 predicted fractures (standardized incidence ratio, 0.95; 95% confidence interval, 0.82-1.10). No significant trends were observed toward increasing fracture risk with inclusion of quintiles of declining renal function (P>.10). In univariate analyses, serum creatinine concentration, creatinine clearance rate, and estimated glomerular filtration rate were associated with greater risk of some fractures. In multivariate analyses, however, decreasing renal function was not found to be a significant risk factor, after adjusting for age, body weight, and bone mineral density.

CONCLUSION

The addition of serum creatinine concentration, creatinine clearance rate, or estimated glomerular filtration rate does not improve fracture risk prediction in postmenopausal white women who have moderate chronic kidney disease. This result can be partly explained by the fact that important risk factors for decreased renal function (eg, advanced age, lower body weight) are already accounted for in most fracture prediction models.

Calciphylaxis: natural history, risk factor analysis, and outcome

BACKGROUND

Calciphylaxis is characterized by ischemic cutaneous ulceration, high mortality, and ineffective treatment.

METHODS

We conducted a retrospective study of 64 patients with calciphylaxis (including 49 dialysis patients age- and sex-matched to 98 dialysis controls).

RESULTS

The estimated 1-year survival rate of calciphylaxis was 45.8%. Risk factors for calciphylaxis included obesity, liver disease, systemic corticosteroid use, calcium-phosphate product more than 70 mg(2)/dL(2), and serum aluminum greater than 25 ng/mL. Survival rates were similar for 16 patients who received parathyroidectomy and 47 who did not. An estimated 1-year survival rate of 61.6% was observed for 17 patients receiving surgical debridement compared with 27.4% for the 46 who did not (P = .008).

LIMITATIONS

The study was limited by its retrospective design and there was no control group for the 15 nondialysis cases.

CONCLUSIONS

Calciphylaxis is multifactorial and usually fatal. Prevention of calciphylaxis may include correction of risk factors identified in this study. Surgical debridement was associated with improved survival, but parathyroidectomy was not.

Total hip arthroplasty in patients with renal failure: a comparison between transplant and dialysis patients

This study analyzed the outcome of total hip arthroplasty (THA) from a single institution of patients with renal failure, including renal dialysis patients (9 patients, 9 hips) and renal transplant patients (28 patients, 36 hips). There were 12 revisions and a 61% complication rate in the transplant group. In the dialysis group, 1 patient was revised, and there was a 33% complication rate. Transplant patients were younger, more active, and lived longer, but had higher cumulative rates of revision and complications with longer follow-up. Dialysis patients, in contrast, had a short survival but a lower rate of complications and revisions. These data differ from previous reports of acceptable outcomes with low complication rates of THA in transplant patients. Efforts to minimize complications in these patients are justified.

Association of heparin-dependent antibodies and adverse outcomes in hemodialysis patients: a population-based study

OBJECTIVE

To determine whether some adverse outcomes of hemodialysis could be explained by subclinical heparin-induced thrombocytopenia (HIT).

PATIENTS AND METHODS

Platelet factor 4 (PF4)-heparin antibodies were measured by enzyme-linked immunosorbent assay In a population-based cohort of hemodlalysis patients. Participants were then followed up prospectively for thromboembollc events, cardiovascular events, or death.

RESULTS

Of the 59 hemodialysis patients residing In Olmsted County, Minnesota, 57 (97%) agreed to study participation. The mean +/- SD age of the patients was 64 +/- 17 years (median hemodialysis duration, 23 months), and 27 (47%) were women. The enzyme-linked Immunosorbent assay was positive for PF4-heparin antibodies in 2 patients (3.5%). The PF4-heparin antibody content varied over a 10-fold range and was not associated with the duration of hemodialysis (P = .99). During a median follow-up of 798 days, 16 thrombotic events, 37 cardiovascular events, and 23 deaths (Including 13 cardiovascular deaths) occurred. After adjusting for the Framingham risk score, the all-cause mortality rate was significantly higher for patients with the highest tertile of PF4-heparln antibody content compared with patients in the lower tertilles (hazard ratio, 2.47; P = .03). Furthermore, 8 (73%) of deaths in this tertile were due to cardiovascular causes (hazard ratio, 4.14; P = .02).

CONCLUSIONS

Despite repetitive heparin exposure, the prevalence of HIT In patients undergoing maintenance hemodialysis is no greater than that anticipated for other patient populations. However, to our knowledge, this is the first study to show an association between elevated PF4-heparin antibodies and Increased mortality rates in hemodlalysis patients.

Magnitude and impact of abnormal mineral metabolism in hemodialysis patients in the Dialysis Outcomes and Practice Patterns Study (DOPPS)

BACKGROUND

Mineral metabolism has emerged as an important predictor of morbidity and mortality in dialysis patients, independent of bone and muscle concerns. Several expert panels have issued management guidelines for mineral metabolism.

METHODS

The state of mineral metabolism (serum parathyroid hormone [PTH], phosphorus, calcium, and calcium-phosphorus product) was described for representative samples of patients and facilities from 7 countries (France, Germany, Italy, Japan, Spain, United Kingdom, and United States) participating in the Dialysis Outcomes and Practice Patterns Study (DOPPS I, 1996-2001; DOPPS II, 2002-2004).

RESULTS

A relatively modest percentage of patients fell within the guideline range for PTH (21.4% in DOPPS I, 26.2% in DOPPS II), serum phosphorus (40.8%, 44.4%), albumin-corrected serum calcium (40.5%, 42.5%), and calcium-phosphorus product (56.6%, 61.4%). Results were not dramatically different across countries. The majority of patients not within guideline ranges had high serum levels of phosphorus (51.6% in DOPPS I, 46.7% in DOPPS II), calcium (50.1%, 48.6%), and calcium-phosphorus product (43.4%, 38.6%) and low (<150 pg/mL) concentrations of PTH (52.9%, 47.5%). It was rare for patients to fall within recommended ranges for all indicators of mineral metabolism; 23% to 28% fell within guideline for at least 3 measures and only 4.6% to 5.5% of patients were within range for all 4. The risks of all-cause and cardiovascular mortality were directly and independently associated with each of the 4 indicators.

CONCLUSION

The DOPPS provides a useful comparison benchmark for the state of mineral metabolism management of patients with kidney disease; it also affirms the association between mineral metabolism and important patient outcomes.

Vestibular toxicity due to inhaled tobramycin in a patient with renal insufficiency

Inhaled tobramycin is being used increasingly in patients with cystic fibrosis and other forms of bronchiectasis for treatment of bronchial colonization with Pseudomonas aeruginosa. The goal of inhaled antibiotics is to provide maximal concentrations at the site of infection without risking systemic toxicity. We report an unusual case of reversible vestibular toxicity due to inhaled tobramycin in a patient with renal failure who was undergoing hemodialysis. Although systemic absorption after inhaled tobramycin is reportedly negligible, no recommendations have been published regarding monitoring of serum concentrations in patients receiving this form of therapy. We suggest that clinicians consider monitoring serum concentrations of tobramycin in patients at risk of renal toxicity and/or ototoxicity, such as those with predisposing renal or otologic compromise. Further studies in at-risk patients are needed to determine the optimal frequency and timing of such monitoring.

Long-term fracture risk following renal transplantation: a population-based study

Abnormal bone metabolism is a recognized complication of end-stage renal disease, but fracture risk following renal transplantation has not been well quantified. We followed the 86 Olmsted County, Minnesota, residents who underwent initial renal transplantation in 1965-1995 for 911 person-years (median, 10.6 years per subject) in a retrospective cohort study. Fractures, and possible risk factors, were assessed through review of each subject's complete community medical records. Altogether, 117 fractures were observed during follow-up extending to 33 years. The cumulative incidence of any fracture at 15 years was 60% versus 20% expected ( P<0.001). There was a significantly increased risk of fractures generally [standardized incidence ratio (SIR), 4.8; 95% CI, 3.6-6.4] and vertebral (SIR, 23.1; 95% CI, 12.3-39.6) and foot fractures (SIR, 8.4; 95% CI, 5.1-12.9) especially. Age at first transplantation, renal failure due to diabetes, pancreas transplantation, peripheral neuropathy, peripheral vascular disease and blindness were all associated with overall fracture risk. In a multivariate analysis, however, only age and diabetic nephropathy were independent predictors of fracture risk generally, while higher activity status was protective. Diabetes was the only independent predictor of lower limb fractures, whereas age and osteoporosis history predicted vertebral fractures. Cumulative corticosteroid dosage was not associated with increased fracture risk in this analysis. Despite the fact that our patients had few risk factors for preexisting bone disease attendant to postmenopausal osteoporosis, prior corticosteroid use or renal osteodystrophy, these data indicate that renal transplantation is associated with a significant increase in fracture risk among unselected patients in the community. Diabetic patients, particularly, experience excess lower limb fractures. Patients and their care providers should be aware of this elevated fracture risk, which continues long-term.

The effects of sevelamer and calcium acetate on proxies of atherosclerotic and arteriosclerotic vascular disease in hemodialysis patients

BACKGROUND

We recently determined that in hemodialysis patients, the use of calcium salts to correct hyperphosphatemia led to progressive coronary artery and aortic calcification as determined by sequential electron beam tomography (EBT) while the use of the non-calcium-containing binder sevelamer did not. Whether the specific calcium preparation (acetate vs. carbonate) might influence the likelihood of progressive calcification was debated.

METHODS

To determine whether treatment with calcium acetate was specifically associated with hypercalcemia and progressive vascular calcification, we conducted an analysis restricted to 108 hemodialysis patients randomized to calcium acetate or sevelamer and followed for one year.

RESULTS

The reduction in serum phosphorus was roughly equivalent with both agents (calcium acetate -2.5 +/- 1.8 mg/dl vs. sevelamer -2.8 +/- 2.0 mg/dl, p = 0.53). Subjects given calcium acetate were more likely to develop hypercalcemia (defined as an albumin-corrected serum calcium > or =10.5 mg/dl) (36 vs. 13%, p = 0.015). Treatment with calcium acetate (mean 4.6 +/- 2.1 g/day - equivalent to 1.2 +/- 0.5 g of elemental calcium) led to a significant increase in EBT-determined calcification of the coronary arteries (mean change 182 +/- 350, median change +20, p = 0.002) and aorta (mean change 181 +/- 855, median change +73, p < 0.0001). These changes were similar in magnitude to those seen with calcium carbonate. There were no significant changes in calcification among sevelamer-treated subjects.

CONCLUSION

Despite purported differences in safety and efficacy relative to calcium carbonate, calcium acetate led to hypercalcemia and progressive vascular calcification in hemodialysis patients.

Infective Endocarditis in Patients with Kidney Failure: Chronic Dialysis and Kidney Transplant

Physicians who treat patients with infective endocarditis (IE) are encountering a growing number of dialysis and kidney transplant patients. Both groups have 30 to 100 times higher risk of IE, with 1-year mortalities of 40% to 60%. The predominant organisms causing IE are gram positive, with 60% to 80% of cases due to Staphylococcus aureus, and another 10% to 20% of cases due to coagulase-negative staphylococci. Renal transplant patients may develop fungal IE, but this risk is primarily in the first 3 months after transplant. In addition to blood cultures, transesophageal echocardiogram is the most useful diagnostic examination for IE in these patients. Initial antibiotic therapy, pending final culture and antibiotic susceptibility results, should provide coverage against the most common organisms and allow for the potential of either methicillin or vancomycin-resistant species. Removal of infected hemodialysis access devices and at least 4 to 6 weeks of intravenous antibiotics are recommended. Antibiotic prophylaxis against IE has been recommended for all dialysis and renal transplant patients, but this strategy is controversial and unproven.

A time for rediscovery: chronic hemofiltration for end-stage renal disease

Provision of maintenance renal replacement therapy (MRRT) is becoming increasingly challenging. The number of patients requiring MRRT is growing rapidly, while the number of nephrologists, nurses, and other staff available to provide therapy is not increasing at a similar rate. Patients are now older and have more comorbid conditions, which magnifies the complexity of their RRT and makes it increasingly difficult to maintain the quality of care within the limitations of constrained economic resources. The two most commonly used MRRTs are hemodialysis (HD) and peritoneal dialysis (PD). A third modality of MRRT, hemofiltration, is not currently in widespread use in North America. In hemofiltration, plasma is filtered through a highly permeable, biocompatible synthetic membrane and waste products are removed by convection and solvent drag as the filtrate moves across the membrane. Hemofiltration equipment constantly monitors the rate of plasma removal and administers a sterile, nonpyrogenic replacement solution at an appropriate rate to replace the waste-laden ultrafiltrate and avoid vdume depletion in the patient. Hemofiltration may offer some potential clinical advantages to the MRRT patient, including better hemodynamic and cardiovascular stability, enhanced removal of middle molecular weight toxins, increased comfort, and therapy preference. Some reports indicate possible reduced morbidity and mortality and reduced risk of bacterial contamination and inflammation as a result of the use of sterile, ultrapure replacement fluids. Chronic hemofiltration is a relatively simple MRRT option that may offer significant benefits for many patients who have end-stage renal disease (ESRD) and deserves closer consideration for these patients.

Kinetics and dosing predictions for daily haemofiltration

BACKGROUND

Thrice-weekly haemofiltration affords excellent outcome when it is used to treat chronic renal failure patients. Daily haemofiltration (DHF) has recently been proposed as a more intensive therapy option, but the total ultrafiltration or exchange volume (replacement volume plus net ultrafiltration volume) requirements for adequate solute clearances during this novel therapy are unknown.

METHODS

We calculated theoretical solute kinetic profiles during six times per week DHF for comparison with those during thrice-weekly haemodialysis using a high-flux dialyser (HFHD) or during continuous ambulatory peritoneal dialysis (CAPD). HFHD and CAPD were chosen for comparison because K/DOQI guidelines have defined adequate treatment doses for these therapies. Steady-state concentrations were calculated using a two-compartment model of an anuric patient with 35 l of total body water for five solutes: urea, creatinine, vitamin B(12), inulin and beta(2)-microglobulin. Solute distribution volumes and generation rates were taken from the literature, and excess fluid (1 l/day) was assumed to accumulate in and be removed from the extracellular fluid compartment. Theoretical predictions of solute clearance were compared for a 15-l exchange volume/session during DHF, urea Kt/V of 3.6/week during HFHD and urea Kt/V of 2.0/week during CAPD as solute-specific values of the equivalent renal clearance (EKR) and standard Kt/V (stdKt/V) recently defined by Gotch. Additional comparisons of solute clearances were performed between DHF and other daily therapies including six times per week short daily haemodialysis (SDHD) and six times per week nocturnal haemodialysis (NHD).

RESULTS

The calculated results predict that: (i) urea clearance during DHF with an exchange volume of 90 l/week (6x15 l) is equivalent to those during HFHD and CAPD based on urea stdKt/V; and (ii) middle molecule clearances during DHF exceed those achieved during HFHD and CAPD based on either EKR or stdKt/V. As expected, DHF therapy was inferior regarding the clearance of urea and other small solutes to SDHD and NHD; however, DHF therapy was superior to SDHD regarding the clearance of larger middle molecules, approaching the clearances achieved by NHD.

CONCLUSIONS

We predict that an exchange volume of approximately 40% of total body water (15/35 l=43%) per session will provide adequate clearance of small solutes and substantial clearance of middle molecules during six times per week DHF therapy. These theoretical predictions require clinical validation.

Surgical versus medical treatment for calciphylaxis

Background

Calciphylaxis is a rare, painful, life-threatening problem of cutaneous necrosis and refractory healing seen in patients with uraemia and secondary hyperparathyroidism. The pathogenesis involves abnormalities in calcium and phosphorus metabolism, and acute deposition of calcium in tissues.

Methods

The clinical course of 16 patients diagnosed with calciphylaxis at this institution from 1994 to 1998 was reviewed.

Results

Fourteen women and two men, with a mean age of 56 (range 39–70) years, presented with chronic renal disease of various causes, hyperparathyroidism and characteristic skin lesions. All patients underwent intensive medical therapy, including haemodialysis (n = 16), parathyroidectomy (PTX) (n = 7) and skin debridement of cutaneous lesions (n = 8). Mean preoperative serum values in surgical (PTX) versus non-surgical patients were: calcium 9·9 and 9·3 mg dl−1 (P = 0·25); phosphorus 5·8 and 4·9 mg dl−1 (P = 0·04); calcium–phosphorus product 61·6 and 45·2 (P = 0·03); and parathyroid hormone (PTH) 56·8 and 5·9 pmol l−1 (P = 0·0001) respectively. Mean postoperative values for calcium (8·7 mg dl−1), phosphorus (4·2 mg dl−1), calcium–phosphorus product (30·5) and PTH (4·0 pmol l−1) in surgical patients changed significantly (P &lt; 0·05). Median overall survival was 9·4 months with 15 patients now deceased. Median survival was 14·8 and 6·3 months for PTX versus no PTX (P = 0·22), 14·1 and 6·1 months for skin debridement versus no debridement (P = 0·08), 12·4 and 6·6 months for proximal versus distal skin lesions (P = 0·60), and 6·5 and 13·9 months for diabetic versus non-diabetic patients was (P = 0·11).

Conclusion

Calciphylaxis appears to have a female preponderance with a very dismal prognosis. A multidisciplinary approach using frequent haemodialysis to normalize serum calcium and phosphorus levels, and local debridement of skin lesions seems prudent. PTX cannot be recommended routinely in all such patients unless severe secondary hyperparathyroidism with poorly controlled metabolic disturbance mandates surgery. The exact indications for PTX for calciphylaxis remain unclear.

Prospective, randomized evaluation of a cuffed expanded polytetrafluoroethylene graft for hemodialysis vascular access

BACKGROUND

A cuffed expanded polytetrafluoroethylene (ePTFE) hemodialysis graft was developed to address the problem of recurrent stenosis at the graft-vein anastomosis. The purpose of this study was to compare graft patency and blood flow rates of cuffed and noncuffed (standard) ePTFE grafts placed for hemodialysis access.

METHODS

Forty-eight patients were prospectively randomized and followed for up to 24 months after placement of a cuffed or standard ePTFE graft for hemodialysis access. Study end points included time to graft failure and blood flow rates on hemodialysis.

RESULTS

Risk factors for graft failure were similar in both groups. However, the overall incidence of graft failure was significantly lower in the cuffed ePTFE graft group (P =.039). Graft patency rates in the cuffed versus standard groups were 64% versus 32% at 12 months (P =.037) and 58% versus 21% at 24 months (P =.0213). No cuffed ePTFE graft failed as a result of venous outflow stenosis. Average graft flow rates were similar when first measured 3 months postoperatively (845 mL/min, cuffed vs 715 mL/min, standard; P =.51) but declined more rapidly in the standard group (12 months, 623 vs 253 mL/min [P =.037]; 24 months, 531 vs 121 mL/min [P =.012]).

CONCLUSIONS

The cuffed ePTFE graft was associated with increased blood flow rates during hemodialysis and improved graft patency compared with a standard ePTFE graft. Our results suggest a beneficial effect of the cuffed venous geometry for hemodialysis vascular access.

Preliminary experience with a cuffed ePTFE graft for hemodialysis vascular access

The purpose of this study was to determine graft patency and blood flow rates in recipients of a new cuffed ePTFE graft (Venaflo graft) used for hemodialysis access. A pilot study was conducted with 12 (7 men, 5 women) consecutive patients (age range, 36-76 yr; mean, 65 yr). All patients were recipients of a new cuffed PTFE graft placed for hemodialysis access. Seven were high risk because of a prior history of clotted hemodialysis accesses (1-6; mean, 3.3). Blood flow rates were determined by ultrasound dilution technique at 3 month intervals. One year and 2 year overall graft patency rates were 90.9% and 68.2%, respectively. One graft (high risk, six prior grafts) was lost to thrombosis in the first year; two grafts (one high risk, four prior grafts) were lost to thrombosis in the second year of follow-up. No graft thrombosis resulted from stenosis at the graft-vein anastomosis. Blood flow rates ranged from 550 to 2,110 ml/min (mean, 1,086 ml/min; n = 8) when first measured 3 months after graft placement. Similar flow rates were observed at 12 months (mean, 1,043 ml/min; n = 7) and 24 months (mean, 1,014 ml/min; n = 4) in grafts available for comparison. Dialysis flow rates in excess of 350 ml/min were possible with all patent grafts. A cuffed ePTFE graft provided stable blood flow and satisfactory graft patency during 2 years of follow-up, even in high risk patients with a prior history of vascular access thrombosis.

Evaluation of long-term survival after successful percutaneous coronary intervention among patients with chronic renal failure

We studied the long-term outcomes after percutaneous coronary intervention in dialysis patients and in patients with chronic renal failure (CRF) (serum creatinine > or = 3.0 mg/dl). All-cause mortality at 1 year was 2.9% for the control group, 16.2% for the group with CRF, and 14.1% for dialysis patients. Cardiac mortality at 1 year was 1.9% for ther control group, 15.2% for the group with CRF, and 10.0% for dialysis patients.

Is calciphylaxis best treated surgically or medically?

BACKGROUND

Calciphylaxis is a rare, painful, life-threatening problem of cutaneous necrosis and refractory healing in patients with uremia and secondary hyperparathyroidism. The pathogenesis involves abnormalities in calcium and phosphorus metabolism and acute deposition of calcium in tissues.

METHOD

The clinical course of 16 patients who were diagnosed with calciphylaxis at our institution from 1994 through 1998 was reviewed.

RESULTS

Fourteen female patients and 2 male patients had chronic renal disease, secondary hyperparathyroidism, and characteristic skin necrosis (mean age, 56 years; range, 39-70 years). All patients underwent intensive medical therapy, including ongoing hemodialysis (n = 16 patients), parathyroidectomy (n = 7 patients), and debridement of cutaneous lesions (n = 8 patients). Mean serum values in surgical and nonsurgical patients were significantly different for phosphorus, calcium-phosphorus product, and parathormone levels. Median survival was 9.4 months; 15 patients (93%) have died. The median survival time for parathyroidectomy versus nonparathyroidectomy was 14.8 and 6.3 months (P =.22), for skin debridement versus nondebridement was 14.1 and 6.1 months (P =.08), and for diabetic versus nondiabetic patients was 6.5 and 13.9 months (P =.11).

CONCLUSIONS

Calciphylaxis has a female preponderance, with a dismal prognosis. A multidisciplinary approach that uses frequent hemodialysis to normalize calcium and phosphorus levels and local debridement of skin lesions seems prudent. Parathyroidectomy cannot be recommended routinely in all patients, unless severe hyperparathyroidism mandates intervention.

Patient survival and renal recovery in acute renal failure: randomized comparison of cellulose acetate and polysulfone membrane dialyzers

OBJECTIVE

To investigate survival and renal recovery after dialysis in patients with acute renal failure with use of synthetic membranes compared with substituted cellulose membranes.

PATIENTS AND METHODS

We prospectively studied survival and recovery of renal function of 66 patients with acute renal failure who required intermittent hemodialysis. Patients were randomized to exclusive treatment with either cellulose acetate (CA) or polysulfone (PS) hemodialysis membranes. Additionally, markers of biocompatibility (complement, leukocyte counts, cytokine concentration) were measured at initiation and 1 hour after initiation of dialysis among 10 patients equally distributed between the CA and PS groups.

RESULTS

The cohorts were indistinguishable with respect to age, sex, presence of diabetes mellitus, Acute Physiology and Chronic Health Evaluation II scores, percentage in the intensive care unit (ICU), and adequacy of dialysis. Survival (76% CA, 73% PS; P=.78) and recovery of renal function at 30 days (58% CA, 39% PS; P=.14) were not statistically different in the 2 groups. Among 26 CA patients and 27 PS patients treated in the ICU, survival was not statistically different (73% CA, 67% PS; P=.61); however, the proportion of patients recovering renal function suggested a benefit favoring CA membranes (65% CA, 37% PS; P=.04). Additionally, markers of biocompatibility were not significantly different between groups among the 10 patients equally distributed between the CA and PS groups.

CONCLUSIONS

Overall clinical outcomes among patients with acute renal failure treated with CA hemodialysis membranes and those treated with PS membranes were not significantly different. The observed advantage favoring renal recovery among this ICU population treated with CA hemodialysis membranes warrants further investigation.

Adverse events in chronic hemodialysis patients receiving intravenous iron dextran--a comparison of two products

BACKGROUND

Parenteral iron therapy is required in a majority of chronic dialysis patients who are receiving recombinant human erythropoietin (r-HuEPO) in order to provide adequate iron for erythropoiesis. At this time, there are only two formulations of parenteral iron dextran available for clinical use in the USA. These two preparations of iron dextran have different physical and chemical characteristics that might affect the adverse events experienced by dialysis patients receiving iron dextran.

METHODS

We performed a retrospective analysis of all 665 courses of parenteral iron dextran which were administered in our hemodialysis unit from June 1992 through July 1997. An adverse event (AE) was defined as any event which led to interruption of the prescribed course of iron therapy or precluded subsequent administration of parenteral iron in the presence of documented iron deficiency. Database elements included patient age, gender, cause of renal failure, and prior history of drug allergy. The average hemoglobin value and serum iron parameters (iron, total iron binding capacity (TIBC), percent saturation of TIBC, and ferritin) were recorded both pre- and post-iron administration, when available. A course of parenteral iron dextran consisted of a 25-mg test dose, followed by four or five doses of 300 mg each. Iron dextran was infused into the venous limb of the hemodialysis blood circuit over the last 30-60 min of a dialysis treatment. The two forms of iron dextran were designated as Iron A (molecular weight = 165,000) and Iron B (molecular weight = 267,000).

RESULTS

Fifty-seven percent of our patients were male, 92% were of white race, and diabetes was the most common cause of renal failure (34%). Sixty-four percent of the patients were 60 years of age or older, and 39% had a history of allergy to one or more drugs. We observed 33 AEs during the administration of parenteral iron dextran, and these AEs occurred in 21 courses of parenteral iron dextran administration. Eighteen of the AEs were gastrointestinal in nature; 7 AEs were cutaneous in nature, 6 AEs had systemic manifestations, while only 2 AEs caused respiratory problems. Two of the AEs were felt to be anaphylactoid in nature. Female gender (p = 0.06) and iron dextran product (p = 0.02) were identified as potential risk factors for the development of an AE. There were 468 courses of Iron A administered, 10 of these courses were complicated by 15 AEs (one or more AE per course). One hundred and ninety-seven courses of Iron B were administered and 11 (5.6%) courses were complicated by the development of 18 AEs (9.1 AEs per 100 courses). Serum iron rose by 22 microg/dl and TIBC saturation increased by 14% after the administration of parenteral iron. The average serum ferritin level rose by 430 microg/l and hemoglobin values rose by an average of 0.8 g/dl. There were no significant differences in the changes of iron parameters or hemoglobin levels between the two iron dextran preparations.

CONCLUSIONS

The administration of parenteral iron dextran to chronic hemodialysis patients has a relatively high degree of safety. Both iron products were equally efficacious in increasing serum iron parameters and hemoglobin levels. Even when corrected for other factors, there was a significant difference in the observed AEs between the two formulations of parenteral iron dextran. Our observations, if true, may have important implications for the management of anemia in chronic hemodialysis patients. If a significant number of AEs prohibit the administration of a specific iron dextran product to a large number of chronic hemodialysis patients, then anemia management may become suboptimal. In the future, newer iron products may provide even safer alternatives for the administration of parenteral iron to chronic hemodialysis patients.

Infective endocarditis in patients receiving long-term hemodialysis

OBJECTIVE

To ascertain the predominant characteristics of patients receiving long-term dialysis who develop infective endocarditis (IE).

PATIENTS AND METHODS

We reviewed the records of all chronic hemodialysis patients who had IE at Mayo Clinic, Rochester, Minn, between 1983 and 1997.

RESULTS

Twenty episodes of IE occurred in 17 patients. One patient had 3 episodes of IE, and 1 patient had 2 episodes of IE; each episode was caused by a different organism. The mean +/- SD age of our patients was 63 +/- 11 years; there were 13 males; 6 patients had diabetes mellitus; and the mean +/- SD duration of hemodialysis prior to IE was 24.2 +/- 20.5 months. This analysis included 10 episodes of IE (occurring in 9 patients) within the Mayo Clinic Dialysis System during which time 223,358 hemodialysis treatments were delivered, giving a rate of 10 IE episode per 223,336 hemodialysis treatments. Among all 20 IE episodes, there were 14 synthetic arteriovenous grafts, 4 permanent venous dialysis catheters, 2 temporary venous dialysis catheters, and 2 native arteriovenous fistulas (2 accesses in 2 patients), and access had been in place for a mean +/- SD of 15.9 +/- 18.6 months. The portal of infection was the hemodialysis access in 13 episodes of IE. The causative organisms for IE were Staphylococcus aureus in 8 cases, Enterococcus sp in 4 cases, viridans streptococcus in 3 cases, Staphylococcus epidermidis in 2 cases, and 1 case each of Streptococcus bovis, group G beta-hemolytic streptococcus, and Aspergillus sp. The mitral valve was involved in 9 cases, the aortic valve was involved in 5 cases, and the tricuspid and pulmonic valves were involved in 1 case each. Patient survival (after the first episode of IE) was 71% at 30 days; 53% at 60 days; and 35% at 1 year. Echocardiography was performed in 19 episodes of IE. The transthoracic echocardiogram was 62.5% sensitive and 40% specific for the presence of definite or probable vegetations. Univariate analysis for factors affecting 60-day survival show that presence of right-sided IE, vegetation size greater than 2.0 cm3, diagnosis of diabetes mellitus, and initial leukocyte count greater than 12.5 x 10(9)/L were poor prognostic factors. Aortic valve involvement carried a better prognosis.

CONCLUSIONS

Infective endocarditis in hemodialysis patients is relatively infrequent but has a high mortality. Patients with synthetic intravascular dialysis angioaccess (synthetic grafts and venous catheters) are more likely to develop IE than patients with native arteriovenous fistulas. Transesophageal echocardiography is a preferred echocardiographic study for suspected cases of IE. Prolonged antibiotic therapy is needed for all patients, and close monitoring is needed for patients with right-sided IE, large vegetations, diabetes mellitus, and an elevated leukocyte count.

Effect of volume reduction on mitral annular diastolic velocities in hemodialysis patients

The effect of volume reduction on various diastolic Doppler parameters of left ventricular filling was assessed in 13 patients before and after hemodialysis. Volume reduction decreased early diastolic mitral annular velocities to a lesser extent than early diastolic mitral inflow velocities.

Reduced synthesis of muscle proteins in chronic renal failure

Muscle wasting and weakness occur frequently in patients with chronic renal failure. The mechanism(s) by which these abnormalities occur is unclear. We hypothesized that such findings were due to defective muscle protein synthesis. We measured synthetic rates of mixed muscle proteins, myosin heavy chain, and mitochondrial proteins in serial muscle biopsy samples during a continuous infusion of L[1-(13)C]leucine from 12 patients with chronic renal failure and 10 healthy control subjects under identical study conditions. Patients with chronic renal failure have significantly lower synthetic rates of mixed muscle proteins and myosin heavy chain (27 and 37% reductions, respectively, P < 0.05 and P < 0.02). Significant declines in the synthetic rates of muscle mitochondrial protein (27%) (P < 0.05), muscle cytochrome c-oxidase activity (42%) (P < 0.007), and citrate synthase (27%) (P < 0.007) were also observed in patients with chronic renal failure. The synthetic rates of muscle proteins and activity of mitochondrial enzymes were negatively correlated to the severity of renal failure. These results indicate that in chronic renal failure there is a decrease in the synthesis of muscle contractile and mitochondrial proteins and a decrease in muscle mitochondrial oxidative enzymes. Reduced synthetic rate of several muscle proteins is the likely biochemical basis of muscle loss and muscle weakness in people with chronic renal failure.

A practical approach to the management of patients with chronic renal failure

The number of patients with significant chronic renal failure is expanding rapidly in the United States. All physicians and medical-care providers will have an increasingly important role in the detection and management of renal failure in patients who are not undergoing dialysis. Patients with diabetes or hypertension should be carefully monitored for the development of renal insufficiency by using screening tools such as blood pressure measurement, determination of serum creatinine, urinalysis, and determination of 24-hour urinary microalbuminuria. In order to slow the progression of renal disease, attenuate uremic complications, and prepare patients with renal failure for renal replacement therapy, all medical-care providers should "take care of the BEANS." Blood pressure should be maintained in a target range lower than 130/85 mm Hg, and in many patients, angiotensin-converting enzyme inhibitors may be beneficial. Erythropoietin should be used to maintain the hemoglobin level at 10 to 12 g/dL. Access for long-term dialysis should be created when the serum creatinine value increases above 4.0 mg/dL or the glomerular filtration rate declines below 20 mL/min. Nutritional status must be closely monitored in order to avoid protein malnutrition and to initiate dialysis before the patient's nutritional status has deteriorated. Nutritional care also involves correction of acidosis, prevention and treatment of hyperphosphatemia, and administration of vitamin supplements to provide folic acid. Specialty referral to nephrology should occur when the creatinine level increases above 3.0 mg/dL or when the involvement of a nephrologist would be beneficial for ongoing management of the patient.

Improved biochemical variables, nutrient intake, and hormonal factors in slow nocturnal hemodialysis: a pilot study

OBJECTIVE

To determine whether slow nocturnal hemodialysis (SNHD) can be safely performed in patients with end-stage renal disease to improve the biochemical and clinical outcome.

MATERIAL AND METHODS

We conducted an 8-week pilot study in nondiabetic adult patients, who underwent dialysis 6 nights per week for 8 hours each night. A dialysate flow rate of 300 mL/min and a blood flow rate of 250 mL/min, through an internal jugular dual-lumen venous catheter, were used. The equipment used was a COBE Centry System 3 dialysis machine and Fresenius F-80 (1.8 m2) or Baxter CT 190 (1.9 m2) dialyzers. Five patients were enrolled in the study.

RESULTS

Two patients did not complete the study because of catheter-related infections--one at day 7 and one after 4 weeks of SNHD. All patients had improved blood pressure control, and no intradialytic adverse events occurred. Dietary intake improved, urea and creatinine levels significantly decreased, and weekly delivery of dialysate increased on SNHD. Potassium, chloride, beta 2-microglobulin, phosphorus, calcium, and high-density lipoprotein cholesterol all improved on SNHD. Serum testosterone increased in the three men on SNHD, but parathyroid hormone, luteinizing hormone, and follicle-stimulating hormone remained unchanged. Erythropoietin levels increased on SNHD, despite no change in exogenous erythropoietin doses in three patients and discontinuation of administration of erythropoietin in one. The following biochemical factors did not change significantly: serum sodium, bicarbonate, vitamin B12, folate, alkaline phosphatase, total cholesterol, triglycerides, and albumin.

CONCLUSION

Higher doses of hemodialysis benefit nutrition, improve biochemical variables, and may improve many hormonal systems.

Renal and urologic complications of inflammatory bowel disease

Renal and urologic complications are not uncommon in patients with inflammatory bowel disease, and can be directly or indirectly related to the underlying disease process or its treatment. Many of these patients have asymptomatic disease, or the urinary symptoms are nonspecific or overshadowed by bowel symptoms. By the time a urinary complication is considered, significant disease progression or renal damage may have occurred. These risks necessitate a high degree of diligence and periodic urologic evaluation as part of the long-term management of patients with inflammatory bowel disease.

Improved preservation of residual renal function in chronic hemodialysis patients using polysulfone dialyzers

Our objective was to determine whether patients with chronic renal failure requiring maintenance hemodialysis retain intrinsic renal function longer when using reprocessed polysulfone (PS) membrane hemodialyzers or single-use cellulose acetate (CA) membrane hemodialyzers. Fifty consecutive patients with residual renal function (urea clearance > 2.0 mL/min) using PS dialyzers were compared with a retrospective, disease- and time-matched population of patients using CA dialyzers. Endogenous urea clearance was measured every 3 months in all patients with remaining residual function. Other data collected included age, sex, cause of chronic renal failure, use of angiotensin-converting enzyme inhibitors or calcium channel blockers, and hemodynamic stability during hemodialysis. All patients were observed for at least 6 months while using a single type of dialyzer. Study end points included loss of residual renal function (urea clearance < 1.0 mL/min), death, transplant, transfer to peritoneal dialysis, or change of dialyzer. The PS and CA groups of patients were well matched for sex, age, initial renal clearance, predialysis blood pressure, and hemodynamic stability during hemodialysis. The PS patients had a higher delivered Kt/V (1.34 +/- 0.30 [mean +/- SD]) than the CA patients (1.06 +/- 0.20). The PS group had a higher average urea clearance than the CA group after 4 to 9 months of dialysis (2.8 +/- 2.6 mL/min v 1.7 +/- 1.6 mL/min, respectively), after 10 to 15 months of chronic dialysis (2.0 +/- 2.4 mL/min v 1.1 +/- 1.5 mL/min, respectively), and after 16 to 21 months of dialysis (1.3 +/- 1.9 mL/min v 0.5 +/- 1.1 mL/min, respectively; all P < 0.03, t-test). After 22 to 24 months of dialysis, the difference between the two groups was not significant. When comparing patients with identical causes of chronic renal failure, there were no differences between the PS and CA groups for those with diabetes mellitus, tubulointerstitial disease, or polycystic disease. Patients with parenchymal renal disease (glomerulonephritis or nephrosclerosis) had markedly better retention of intrinsic renal function with PS than with CA dialyzers (all P < 0.01). Kaplan-Meier analysis for retention of intrinsic renal function showed that PS patients with parenchymal renal disease had a mean of 23 months before loss of intrinsic renal function, whereas for CA patients the mean was 11 months before loss of intrinsic renal function (P = 0.0005). Cellulose acetate patients lost renal function at an average rate of 0.27 +/- 0.22 mL/min/mo, whereas for PS patients the rate was 0.14 +/- 0.56 mL/min/mo (P = 0.06, rank sum). CA patients with parenchymal renal disease lost renal function at a rate of 0.29 +/- 0.22 mL/min/mo, whereas for PS patients the rate was 0.0 +/- 0.8 mL/min/mo (P = 0.004, rank sum). Age, sex, and the use of either angiotensin-converting enzyme inhibitors or calcium channel blockers did not have an effect on the loss of intrinsic renal function. Patients with nondiabetic parenchymal renal disease receiving chronic hemodialysis with hydrogen peroxide/peroxyacetic acid-reprocessed PS dialyzers and a higher Kt/V lose residual renal function at a slower rate than disease-matched patients using single-use CA dialyzers. Our findings provide further evidence that the choice of dialyzer membrane may have an effect on intrinsic renal function.

Renal replacement therapy in acute renal failure

The choices regarding renal replacement therapy in acute renal failure have become more complex. The underlying prognosis of the patient should be considered when making the choice of a dialysis treatment. The attending nephrologist must also have a working knowledge of the potential advantages of various dialyzers and continuous renal replacement therapies to maximize the potential for recovery of patients with acute renal failure.

The uremic gangrene syndrome: improved healing in spontaneously forming wounds following subtotal parathyroidectomy

Patients with end-stage renal disease often demonstrate retarded healing of surgical wounds, but the basis for spontaneous wound formation in these patients is less well understood. We report our experience with four patients with a unique clinical entity previously described as the uremic gangrene syndrome (also known as calciphylaxis) that involves spontaneously forming and insidiously progressive wounds of the skin and soft tissue in uremic patients with hyperparathyroidism. The importance of recognizing this phenomenon relates to the potential benefit to wound-healing efforts resulting from subtotal parathyroidectomy and adjustment of serum calcium and phosphate levels when severe hyperparathyroidism is present. Disrupted parathyroid homeostasis as a mechanism for soft-tissue ischemia and subsequent infarction is supported by wound biopsies demonstrating microarterial calcification. As experts in factors resulting in refractory wounds, plastic surgeons need be aware of this peculiar vulnerability for spontaneously forming wounds in uremic patients. Clinical and laboratory findings, success with wound treatment in four patients, and currently popular pathophysiologic mechanisms are discussed.