Marianne Rix

Efficacy and Tolerability of Sevelamer Carbonate in Hyperphosphatemic Patients Who Have Chronic Kidney Disease and Are Not on Dialysis

BACKGROUND AND OBJECTIVES Sevelamer carbonate is an improved, buffered form of sevelamer hydrochloride developed for the treatment of hyperphosphatemia in patients with chronic kidney disease. This study investigated the ability of sevelamer carbonate to control serum phosphorous in hyperphosphatemic patients who had chronic kidney disease and were not on dialysis. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS This was an open-label, dosage-titration study. Patients with serum phosphorus > or =5.5 mg/dl were enrolled (n = 46). Sevelamer carbonate was administered for 8 wk. Patients were supplemented with native vitamin D (400 IU). The primary efficacy parameter was the change from baseline in serum phosphorous. Secondary measures included the percentage of serum phosphorus responders; changes in serum lipids, calcium-phosphorus product, and bicarbonate; and safety and tolerability. RESULTS Sevelamer carbonate treatment resulted in a statistically significant decrease in mean serum phosphorous levels from baseline to end of treatment. A total of 75% of patients with stage 4 and 70% of patients with stage 5 chronic kidney disease achieved the target serum phosphorous at the end of treatment. There were statistically significant decreases in serum calcium-phosphorus product and total and low-density lipoprotein cholesterol at the end of treatment and a statistically significant increase in mean serum bicarbonate levels (from 16.6 to 18.2 mEq/L). Sevelamer carbonate was well tolerated. CONCLUSIONS Sevelamer carbonate is an effective and well-tolerated therapy for the control of phosphorous levels in hyperphosphatemic patients who have chronic kidney disease and are not on dialysis.

Volume Flow in Arteriovenous Fistulas Using Vector Velocity Ultrasound

Volume flow in arteriovenous fistulas for hemodialysis was measured using the angle-independent ultrasound technique Vector Flow Imaging and compared with flow measurements using the ultrasound dilution technique during dialysis. Using an UltraView 800 ultrasound scanner (BK Medical, Herlev, Denmark) with a linear transducer, 20 arteriovenous fistulas were scanned directly on the most superficial part of the fistula just before dialysis. Vector Flow Imaging volume flow was estimated with two different approaches, using the maximum and the average flow velocities detected in the fistula. Flow was estimated to be 242 mL/min and 404 mL/min lower than the ultrasound dilution technique estimate, depending on the approach. The standard deviations of the two Vector Flow Imaging approaches were 175.9 mL/min and 164.8 mL/min compared with a standard deviation of 136.9 mL/min using the ultrasound dilution technique. The study supports that Vector Flow Imaging is applicable for volume flow measurements.

Surveillance for hemodialysis access stenosis: usefulness of ultrasound vector volume flow.

Purpose To investigate if ultrasound vector-flow imaging (VFI) is equal to the reference method ultrasound dilution technique (UDT) in estimating volume flow and changes over time in arteriovenous fistulas (AVFs) for hemodialysis. Materials and methods From January 2014 to January 2015, patients with end-stage renal disease and matured functional AVFs were consecutively solicited to participate in this prospective study. All patients were included after written informed consent and approval by the National Committee on Biomedical Research Ethics and the local Ethics Committee (journal no. H-4-2014-FSP). VFI and UDT measurements were performed monthly over a six-month period. Nineteen patients were included in the study. VFI measurements were performed before dialysis, and UDT measurements after. Statistical analyses were performed with Bland-Altman plot, Students t-test, four-quadrant plot, and regression analysis. Repeated measurements and precision analysis were used for reproducibility determination. Results Precision measurements for UDT and VFI were 32% and 20%, respectively (p = 0.33). Average volume flow measured with UDT and VFI were 1161 mL/min (±778 mL/min) and 1213 mL/min (±980 mL/(min), respectively (p = 0.3). The mean difference was -51 mL/min (CI: -150 mL/min to 46 mL/min) with limits of agreement from -35% to 54%, with a strong correlation (r2 = 0.87). A large change in volume flow between dialysis sessions detected by UDT was confirmed by VFI (p = 0.0001), but the concordance rate was poor (0.72). Conclusions VFI is an acceptable method for volume flow estimation and volume flow changes over time in AVFs.

Risk of Infective Endocarditis in Patients with End Stage Renal Disease

BACKGROUND AND OBJECTIVES Endocarditis is a serious complication in patients treated with RRT. The study aimed to examine incidence and risk factors of endocarditis in patients with ESRD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS The Danish National Registry on Regular Dialysis and Transplantation contains data on all Danish patients receiving renal replacement (hemodialysis, peritoneal dialysis, or kidney transplantation) for ESRD. Incidence of endocarditis was estimated for each RRT modality. Independent risk factors of endocarditis were identified in multivariable Cox regression models. RESULTS From January 1st, 1996 to December 31st, 2012, 10,612 patients (mean age 63 years, 36% female) initiated RRT (7233 hemodialysis, 3056 peritoneal dialysis, 323 pre-emptive kidney transplantation). Endocarditis developed in 267 (2.5%); of these 31 (12%) underwent valve surgery. The overall incidence of endocarditis was 627 per 100,000 person-years in patients receiving RRT. Incidence was higher in patients receiving hemodialysis compared with those receiving peritoneal dialysis or kidney transplantation (1092 per 100,000 person-years, 212 per 100,000 person-years, and 85 per 100,000 person-years, respectively). Adjusted hazard ratios for endocarditis in patients receiving hemodialysis were 5.46 (95% confidence interval [95% CI], 3.28 to 9.10) and 0.41 (95% CI, 0.18 to 0.91) for kidney-transplanted recipients, respectively, as compared with patients in peritoneal dialysis. The incidence of endocarditis in hemodialysis recipients with central venous catheters was more than two-fold higher as compared with those with arteriovenous fistulas. Overall mortality, subsequent to endocarditis, was 22% in-hospital and 51% at 1 year. The first 6 months in RRT, aortic valve disease, and previous endocarditis were identified as significant risk factors of endocarditis. CONCLUSIONS Patients receiving RRT have a high incidence of endocarditis, in particular during hemodialysis treatment using central venous catheters. The first 6 months in RRT, aortic valve disease, and previous endocarditis are significant risk factors for developing endocarditis.

Surveillance of hemodialysis vascular access with ultrasound vector flow imaging

The aim of this study was prospectively to monitor the volume flow in patients with arteriovenous fistula (AVF) with the angle independent ultrasound technique Vector Flow Imaging (VFI). Volume flow values were compared with Ultrasound dilution technique (UDT). Hemodialysis patients need a well-functioning vascular access with as few complications as possible and preferred vascular access is an AVF. Dysfunction due to stenosis is a common complication, and regular monitoring of volume flow is recommended to preserve AVF patency. UDT is considered the gold standard for volume flow surveillance, but VFI has proven to be more precise, when performing single repeated instantaneous measurements. Three patients with AVF were monitored with UDT and VFI monthly for five months. A commercial ultrasound scanner with a 9 MHz linear array transducer with integrated VFI was used to obtain data. UDT values were obtained with Transonic HD03 Flow-QC Hemodialysis Monitor. Three independent measurements at each scan session were obtained with UDT and VFI each month. Average deviation of volume flow between UDT and VFI was 25.7 % (Cl: 16.7% to 34.7%) (p= 0.73). The standard deviation for all patients, calculated from the mean variance of each individual scan sessions, was 199.8 ml/min for UDT and 47.6 ml/min for VFI (p = 0.002). VFI volume flow values were not significantly different from the corresponding estimates obtained using UDT, and VFI measurements were more precise than UDT. The study indicates that VFI can be used for surveillance of volume flow.