Ethanol lock therapy for the treatment of catheter-related infections in haemophilia patients

Summary.  Central venous access devices (CVAD) are increasingly being used for optimal delivery of clotting factor concentrates in patients with haemophilia with poor peripheral venous access. The utility of CVAD is particularly well recognized in young patients starting factor prophylaxis and in patients with inhibitors undergoing immune tolerance induction (ITI). A catheter-related infection (CRI) remains the most common complication of CVAD in haemophilia patients and is the most frequent indication for its removal. Additionally, in some patients the infection results in significant morbidity and mortality and also contributes to failure of the ITI regimen. Ethanol-lock therapy (ELT) is a treatment modality that has been used to treat CRI in patients with indwelling catheters for home parenteral nutrition and chemotherapy. The aim of this study was to report the success in treating CRI in haemophilia patients using ELT. Three severe haemophilia A patients undergoing ITI regimen who developed CVAD infections resistant to conventional management with antibiotics were treated by ELT according to the institutional technique. All three patients responded well to ELT with clearance of the CVAD infection. There were no adverse side effects. To our knowledge, this is the first report of ELT in patients with haemophilia. The role of ELT needs to be investigated in larger studies for treatment of CRI in patients with bleeding disorders.     

In vivo recovery with products of very high purity — assay discrepancies

Summary. In view of reports of FVIII assay discrepancies in post-infusion plasma samples depending on methods used, we compared FVIII results run by each of four different methods following infusion of rFVIII (Kogenate®). Nine persons with haemophilia A were infused with each of two lots of product. Plasma samples were obtained at baseline, and at 10 min, 30 min, 1, 2, 4, 8, 12, 14, 30 and 48 h post-infusion for measurement of FVIII. FVIII assay methods were chromogenic, and one-stage APTT using three different types of activators: micronized, silica, ellagic acid, and kaolin. The same reference plasma standard was used throughout. Results demonstrated a consistent difference in FVIII values, with chromogenic assays being considerably higher than those run by one-stage assays. The discrepancy was greatest when kaolin was the activator. These results point out the problems in attempting to determine the “correct” FVIII level in patient plasma samples following infusion of high purity FVIII preparations. Potential “pitfalls” include the standard used for defining product potency, the methods, reagents, instrumentation and standards used in assaying plasma samples and, in some instances, the characteristics of the product itself. This situation has considerable cost implications, potential impact on patient care, and makes it difficult to compare results between laboratories.