Cephalic arch stenosis: mechanisms and management strategies.

Cephalic arch is a frequent site for the development of stenosis in patients with brachiocephalic fistulae. This is in part owing to the anatomic constraints of the cephalic arch region and the exertion of hemodynamic forces at this site caused by the creation of a brachiocephalic fistula. Multiple interventions have been used to correct stenosis and subsequent fistula dysfunction. These include percutaneous balloon angioplasty using conventional and cutting balloons, endovascular stent insertion, and surgical interventions. It is important to emphasize that the stenosis in this region frequently recurs, is more resistant to angioplasty, and shows a higher rate of rupture during the percutaneous balloon angioplasty procedure compared with peripheral lesions at other sites. Because hemodynamic forces have been postulated to be one of the culprits for the development of stenosis, a new technique of flow reduction has been introduced to combat this problem. This article discusses the etiology, pathophysiology, and current management of cephalic arch stenosis.

At-home short daily hemodialysis improves the long-term health-related quality of life.

Patients with chronic kidney disease treated by in-center conventional hemodialysis (3 times per week) have significant impairments in health-related quality of life measures, which have been associated with increased morbidity and mortality. FREEDOM is an ongoing prospective cohort study measuring the potential benefits of at-home short daily (6 times per week) hemodialysis. In this interim report we examine the long-term effect of short daily hemodialysis on health-related quality of life, as measured by the SF-36 health survey. This was administered at baseline, 4 and 12 months after initiation of short daily hemodialysis to 291 participants (total cohort), of which 154 completed the 12-month follow-up (as-treated cohort). At the time of analysis, the mean age was 53 years, 66% were men, 58% had an AV fistula, 90% transitioned from in-center hemodialysis, and 45% had diabetes mellitus. In the total cohort analysis, both the physical- and mental-component summary scores improved over the 12-month period, as did all 8 individual domains of the SF-36. The as-treated cohort analysis showed similar improvements with the exception of the role-emotional domain. Significantly, in the as-treated cohort, the percentage of patients achieving a physical-component summary score at least equivalent to the general population more than doubled. Hence, at-home short daily hemodialysis is associated with long-term improvements in various physical and mental health-related quality of life measures.

Ertapenem pharmacokinetics and pharmacodynamics during continuous ambulatory peritoneal dialysis.

Scant data exist for the pharmacokinetics (PK) of ertapenem in patients on continuous ambulatory peritoneal dialysis (CAPD). The goals of this study were to characterize the PK profile of ertapenem during CAPD, determine the extent of ertapenem penetration into the peritoneal cavity, and quantify the probability of the target attainment (PTA) profile in the serum and peritoneal cavity. A single-dose PK study was conducted in seven patients on CAPD. Population PK modeling and Monte Carlo simulation determined the probability that ertapenem at 500 mg intravenously (i.v.) every 24 h (q24h) would achieve concentrations in excess of the MIC for 40% of the dosing interval (40% T>MIC, where T is time) in the serum and peritoneal cavity. Monte Carlo simulation was also used to calculate the peritoneal cavity/serum mean and median penetration ratios by estimating the area under the concentration-time curve in the peritoneal cavity and serum (AUC(Peritoneal) and AUC(Serum), respectively) from zero to infinity after a single simulated dose. The population mean (± standard deviation [SD]) values for the apparent volume in the central compartment, clearance, and apparent volume in the peritoneal cavity were 2.78 (0.62) liters, 0.24 (0.07) liters/hr, and 5.81 (2.05) liters, respectively. The mean (SD) AUC(Peritoneal)/AUC(Serum) ratio was 1.039 (0.861), and the median penetration ratio was 0.801 (interquartile range, 0.486 to 1.317). In both the serum and peritoneal cavity, ertapenem at 500 mg i.v. q24h was very likely (>90%) to achieve the pharmacodynamic target for MICs of ≤2 mg/liter. The simulations suggest that 500 mg of ertapenem i.v. q24h is very likely to achieve the exposure target associated with clinical efficacy in both the serum and peritoneal cavity against the range of MIC values deemed susceptible by the Clinical and Laboratory Standards Institute.

Impact of short daily hemodialysis on restless legs symptoms and sleep disturbances.

BACKGROUND AND OBJECTIVES: Restless legs syndrome (RLS) and sleep disturbances are common among in-center hemodialysis patients and are associated with increased morbidity/mortality. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: The FREEDOM study is an ongoing prospective cohort study investigating the benefits of home short daily hemodialysis (SDHD) (6 times/week). In this interim report, we examine the long-term effect of SDHD on the prevalence and severity of RLS, as measured by the International Restless Legs Syndrome (IRLS) Study Group rating scale, and sleep disturbances, as measured by the Medical Outcomes Study sleep survey. RESULTS: 235 participants were included in this report (intention-to-treat cohort), of which 127 completed the 12-month follow-up (per-protocol cohort). Mean age was 52 years, 55% had an arteriovenous fistula, and 40% suffered from RLS. In the per-protocol analysis, among patients with RLS, the mean IRLS score improved significantly at month 12, after adjustment for use of RLS-related medications (18 versus 11). Among patients with moderate-to-severe RLS (IRLS score ≥15), there was an even greater improvement in the IRLS score (23 versus 13). The intention-to-treat analysis yielded similar results. Over 12 months, there was decline in the percentage of patients reporting RLS (35% versus 26%) and those reporting moderate-to-severe RLS (59% versus 43%). There was a similar and sustained 12-month improvement in several scales of the sleep survey, after adjustment for presence of RLS and use of anxiolytics and hypnotics. CONCLUSIONS: Home SDHD is associated with long-term improvement in the prevalence and severity of RLS and sleep disturbances.

The safety and efficacy of an accelerated iron sucrose dosing regimen in patients with chronic kidney disease.

BACKGROUND: Provision of adequate iron to support erythropoiesis in patients with chronic kidney disease (CKD) is time consuming and may present adherence problems for patients in the outpatient setting. We studied an accelerated regimen of high-dose intravenous iron sucrose therapy in a cohort of iron-deficient, anemic CKD patients. METHODS: Intravenous iron sucrose 500 mg was infused over three hours on two consecutive days in 107 CKD patients (glomerular filtration rate, 32.3 +/- 19.6 mL/min/1.73m2, baseline hemoglobin 10.2 +/- 1.7 g/dL). Iron indices (transferrin saturation, ferritin) were measured at baseline and at two and seven days after completion of the iron regimen. Blood pressures were monitored immediately prior to, and hourly throughout the iron sucrose infusions. RESULTS: Transferrin saturation and serum ferritin increased from 18.5 +/- 8.5% and 177 +/- 123.8 ng/mL at baseline to 40.2 +/- 22.3% and 811 +/- 294.1 ng/mL in 102 evaluated patients (P < 0.015). In 55 patients with additional measurements at 7 days post-dosing, the transferrin saturation and ferritin had fallen to 26.3 +/- 10.6% and 691 +/- 261.8 ng/mL (P < 0.015 compared to two days' post-dose). Blood pressure rose slightly, but not significantly, throughout the infusions, and altering the infusion rate was not necessary. Two patients had seven adverse events that were considered related to iron sucrose. CONCLUSION: An accelerated regimen of high-dose intravenous iron sucrose therapy in CKD patients is safe and effective in restoring iron stores, and may potentially save time and improve patient adherence.