Szymon Brzosko

Risk Factors of Nontunneled Noncuffed Hemodialysis Catheter Malfunction

Background: The use of noncuffed nontunneled central venous catheters is a widely accepted method of gaining temporary vascular access for hemodialysis. Malfunction and bacteremia are the main factors limiting catheter survival. Methods: We followed up prospectively 73 hemodialysis catheters (HC) (40 internal jugular, 33 femoral) in order to establish factors influencing HC malfunction. HC malfunction was defined as a catheter that was unable to attain and maintain blood flows of at least 150 ml/min. 73 HC were used for a total 1,100 days. Results: HC malfunction occurred in 23 cases (31.51%) during the study period, giving an overall rate of 21 episodes per 1,000 catheter days at risk. An analysis revealed a higher risk of HC malfunction with the catheterization of the femoral vein compared to the internal jugular vein (hazard ratio (HR) 6.3; 95% confidence interval (CI) 5.3–7.3). After correction for confounding factors in multivariate Cox analysis, the site of the catheterization remained a statistically significant predictor of HC malfunction (HR 5.03, 95% CI 3.83–6.23). After the first week malfunction rate was 42 and 8% for femoral and internal jugular site, respectively (relative risk (RR) for malfunction 5.3 (95% CI, 2.5–8). After the second and third week, the incidence of malfunction was 51 and 14% for femoral and internal jugular vein, respectively (RR 3.6, 95% CI 2.2–5.1). Conclusions: Catheterization of the internal jugular vein is associated with longer catheter survival when compared to the femoral vein. Hemodialysis catheters should be placed, if possible, in internal jugular vein to prevent their premature malfunction.

Low Molecular Weight Iron Dextran Increases Fibroblast Growth Factor-23 Concentration, Together With Parathyroid Hormone Decrease in Hemodialyzed Patients

Fibroblast growth factor (FGF)‐23 inhibits PTH production. Elevated FGF‐23 and parathyroid hormone (PTH) levels are characteristic of hemodialyzed patients. Iron polymaltose was shown to increase FGF‐23 concentration. The effect of intravenous low molecular weight iron dextran (LMID) on these hormones and bone metabolism has not been studied in hemodialysis (HD). Twelve HD patients were prospectively followed up for 3 weeks after a single infusion of LMID. Calcium, phosphate, FGF‐23, PTH, degradation products of C‐terminal telopeptides of type I collagen (CTX) and procollagen I N‐terminal propeptide (PINP) were measured prior to, and at week 1 and week 3 after the LMID administration. FGF‐23 increased significantly from 453.4 (68.6–3971.5) pg/mL at baseline to 971.8 (779.5–3361.4) pg/mL (P = 0.001) at week 1 and started to decrease toward the initial value at week 3. The changes were accompanied by a significant decline in PTH from 367.6 (21.4–1487.4) pg/mL at baseline to 315.7 (16.4–1339.8) pg/mL (P = 0.018) at week 1 and subsequently began to increase toward the initial values. Phosphate, calcium, CTX and PINP did not change over the study course. LMID causes an increase in FGF‐23 concentration together with a decrease in PTH. Our study highlights a pathophysiological element, which may connect suppression of parathyroid glands with intravenous iron supplementation.

Factors associated with early catheter-related complications in peritoneal dialysis

PURPOSE It is advocated to delay the start of peritoneal dialysis (PD) at least 10-14 days after insertion of peritoneal catheter. The aim of this study was to investigate factors associated with catheter-related complications (CRC) in patients starting PD early (1-13 days) (ES) and late (14 days or more) (LS) after catheter implantation. MATERIAL/METHODS Single center, retrospective analysis of CRC occurring within 14 days of follow up after peritoneal dialysis initiation in ES and LS group of patients. RESULTS A total of 97 patients were analyzed. Seventy percent of them were ES. There were significantly more CRC in ES vs. LS (31% vs. 3%, p=0.01). Significantly more mechanical CRC occurred in ES than in LS (21% vs. 0%, p=0.01). Occurrence of infectious CRC did not differ between the groups. In multivariate analysis the only predictor of CRC development was the time elapsed between catheter insertion and beginning of PD (Odds Ratio [OR] 0.80 95% Confidence Interval [95% CI] 0.70-0.91; p=0.001). CONCLUSIONS Each day of delay of PD initiation following peritoneal catheter insertion decreases the odds for development of mechanical CRC.

Renal Handling of Sclerostin in Response to Acute Glomerular Filtration Decline

Deterioration of glomerular filtration rate (GFR) is associated with alterations of bone metabolism. It translates clinically to bone fragility and increased fractures rate among patients with impaired GFR. Recently, sclerostin (SCL) gained much attention as an important factor in pathogenesis of mineral and bone disturbances in patients with renal diseases. There is no data about SCL behaviour in patients with acute GFR decline. The aim of this study was to evaluate the renal handling of SCL. This is a prospective, single-centre observational study in patients undergoing nephrectomy due to urological indications. Serum and urinary SCL levels were measured prior and after nephrectomy. 25 patients were enrolled. After surgery, eGFR significantly declined (from 87.4±19.7 to 67.7±25.7 ml/min/1.73 m(2), p<0.0001). Nephrectomy caused more than 20 times higher renal fractional excretion of SCL [0.15 (interquartile range, IQR 0.09-0.40) vs. 2.78 (IQR 1.51-4.02)%, p<0.001], while its serum level remained intact [0.69 (IQR 0.57-0.90 vs. 0.65 (IQR 0.53-0.88) ng/ml, p=0.4]. The magnitude of eGFR reduction was associated inversely with change in urinary SCL fractional excretion (r=-0.6, p=0.001) and with alteration in serum SCL level (r=-0.5, p=0.01). Our results suggest that increased serum SCL concentrations at moderately reduced GFR are not due to diminished renal clearance. At more severely decreased GFR, elevated SCL concentration results from both increased production and reduced renal elimination.

C-terminal and intact FGF23 in critical illness and their associations with acute kidney injury and in-hospital mortality

Background FGF23 proved its value in prognostication of cardiovascular events and mortality among renal patients and general population. Limited data exist whether FGF23 may have any use in prediction of negative outcomes among critically ill patients admitted to intensive care unit (ICU). Methods Single center cohort study performed among patients admitted to ICU. The primary exposure was FGF23 plasma concentration measured within 24 h of ICU admission. The primary outcome was incident Acute Kidney Injury (AKI) and in‐hospital mortality during the ICU stay. Results The study enrolled 79 patients admitted to ICU. C‐terminal FGF23 (cFGF23) but not intact FGF23 (iFGF23) concentration was significantly elevated in patients, who acquired AKI and non‐survivors (p < .001). ROC analysis of cFGF23 yielded an AUC of 0.81 and 0.85 for prediction of incident AKI and death during ICU stay, respectively. Multivariate analysis showed higher odds for AKI (OR 1.80; 95% CI 1.10–2.96) and in‐hospital mortality (OR 2.85; 95% CI 1.60–5.06) for one unit increase of log transformed cFGF23. Conclusions cFGF23 measurement may serve as a novel biomarker for incident AKI and death among critically ill patients.