Femoral Localization and Higher Ultrafiltration Rate but Not Concentration of Heparin Used for Canal Locking of Hemodialysis Catheter Are Negative Predictors for Its Malfunction

Abstract

Background/Aim: Non-tunneled, temporal hemodialysis (HD) catheters are commonly used as short-term vascular access for the HD procedure. One of their late complications is thrombotic occlusion of the catheter ensuing in their malfunction. A heparin lock is conventionally used for maintaining the patency of the catheter. The aim of the study was to evaluate the influence of heparin concentration used for locking the catheter canals (5,000 vs. 2,500 IU/ml) and some other clinical and laboratory variables at the time of temporal HD catheter functioning. Methods: Catheter malfunction was defined as the inability to attain and maintain a blood flow of at least 150 ml/min. 174 consecutive HD catheters inserted into jugular or femoral veins (114 patients) were followed up and remained in use for a total of 3,284 days. Results: Catheter thrombosis occurred in 53 cases (30.5%) during the study period, giving an overall rate of 16 episodes per 1,000 catheter-days at risk. In univariate Cox proportional hazard analysis, predictors of catheter dysfunction were: femoral localization (HR 4.92, 95% CI 4.30–5.50), acute renal failure (HR 1.75, 95% CI 1.18–2.32), higher mean ultrafiltration (UF) (HR 1.31, 95% CI 0.99–1.63) and higher concentration of hemoglobin (HR 1.15, 95% CI 0.99–1.33). The concentration of heparin used for canal locking did not influence the time of catheter functioning (HR 1.1, p = 0.7). In multivariate Cox proportional hazard analysis (χ² = 38.5, d.f. = 4, p < 0.0001) the remaining statistically independent predictors of catheter malfunction were: femoral localization (HR 5.94, 95% CI 5.27–6.61, p < 0.0001) and higher UF (HR 1.60, 95% CI 1.24–1.94, p < 0.01). Conclusions: A lower concentration of heparin (2,500 IU/ml) prevents catheter thrombosis as effectively as a standard one (5,000 IU/ml). Femoral localization of HD catheters and higher UF during the HD procedure are the factors predisposing for catheter malfunction.

Low concentration of heparin used for permanent catheters canal locking is effective and diminishes the risk of bleeding

“…According to the obtained results, the risk of catheter thrombosis was equal between both groups but we have to bear in mind that the observation period in our study was just 24 h. Noteworthy, it may be speculated based on earlier data that heparin at a concentration from 1,000 to 2,500 IU/ml is equally effective as heparin used at a higher concentrations in prevention of catheter thrombosis [9, 12]. Thus, it seems that with lower heparin concentration the same catheter patency is obtained.…”

“…It was shown earlier [9] that heparin concentration did not adversely affect catheter patency. The aim of the study was to test a hypothesis that the lower heparin concentration used for canal locking limits bleeding episodes in HD after PC insertion.…”

Catheter Management in Hemodialysis Patients

“…The heparin concentration used for locking has been reduced because catheter lumens have increased in volume so as to reduce the possibility of unintentional systemic anticoagulation of patients (26 -29). Locking with lower heparin concentrations (2500 or 1000 U/ml) prevents catheter thrombosis as efficiently as 5000 U/ml (30,31). Heparin loss ("leak phenomenon") through diffusion from the lumen within the first hour or after injecting the locking solution (slow versus fast) may accidentally administer up to half the anticoagulant systemically (27) and may explain reports of bleeding episodes after heparin lock (32,33).…”

THE CLINICAL APPLICATION OF CRRT—CURRENT STATUS: Vascular Access for Continuous Renal Replacement Therapy

“…The lower blood flows (150–250 ml/minute) might be adequate for CRRT and the HDC can be used until the patient is more stable to be switched to IHD. One recent study of temporary HDCs showed that femoral localization was associated with a higher risk for thrombosis, when compared to the IJ site (6).…”