Consensus recommendations for use of central venous access devices in haemophilia.

Venous access is essential for delivery of haemophilia factor concentrate. Wherever possible, peripheral veins remain the route of choice, and the use of central venous access devices (CVADs) should be limited to cases of clear need in patients with caregivers able to exercise diligence in CVAD care and should continue no longer than necessary. CVADs are of recognized value for repeated administration of coagulation factors in haemophilia, particularly for prophylaxis and immune tolerance therapy and in young children. Evidence to guide best practices has been fragmentary, and standardized methods for CVAD usage have yet to be established. We have developed management recommendations based upon available published evidence as well as extensive clinical experience. These recommendations address patient and CVAD selection; CVAD placement, care and removal; caregiver/patient guidance; and complications, including infection and thrombosis. In the absence of inhibitors, ports are recommended, primarily because of fewer associated infections than with external catheters. For patients with inhibitors, ports also appear to be associated with fewer infections. Infection is the most frequent complication, and recommendations to prevent and treat infections are supported by extensive clinical data and experience. Strict adherence to handwashing and aseptic technique are essential elements of catheter care. Evidence-based data regarding the detection and treatment of CVAD-related thrombotic complications are limited. Caregiver education is an integral part of CVAD use and the procedural practices of users should be regularly re-assessed. These recommendations provide a basis for sound current CVAD practice and are expected to undergo further refinements as new evidence is compiled and clinical experience is gained.

Type 2B vWD: the varied clinical manifestations in two kindreds.

Type 2B von Willebrand's disease (vWD) is associated with spontaneous binding of large von Willebrand factor (vWF) multimers to platelets in vivo, followed by clearance of both the large multimers and platelets resulting in thrombocytopenia, which may be intermittent, mild to severe, and may be exacerbated by stress such as infection or pregnancy. We report our experience in two kindreds (49 caucasian individuals) with type 2B vWD and discuss their varied clinical manifestations. The largest kindred (45 patients) was traced back five generations to a presumed index case. The genetic defect in this kindred was identified as a missense mutation, with a C to T transition at a CpG dinucleotide (nucleotide 3916) resulting in an amino acid substitution (Arg 543 to Trp) within the glycoprotein Ib binding domain of vWF. Ristocetin cofactor activity varied from < 10 to 28%, and factor VIII activity from 7 to 69%. Analysis of von Willebrand multimers consistently revealed loss of large molecular weight forms. Platelet counts in those with thrombocytopenia varied from 10 x 10(9) L(-1) to 120 x 10(9) L(-1). The severity of thrombocytopenia has also varied within the same individual during the period of follow-up. The clinical manifestations were varied and ranged from mild to moderate spontaneous bleeding episodes, including epistaxis, menorrhagia and gastro-intestinal haemorrhage. Severe bleeding episodes were observed in those undergoing surgery (both elective and non-elective), and in a few patients despite aggressive replacement with exogenous source of intact vWF, antifibrinolytics when indicated, and a near normal platelet count. Thrombotic disease may be a rare and unusual sequela of this disorder as was noted in one of our patients. Obtaining a platelet count at birth in infants of mothers with type 2B vWD who exhibit thrombocytopenia, may help in the earlier detection of infants at risk for thrombocytopenia.