Hereditary and acquired thrombophilic disorders complicating vascular access in haemodialysis: O. Sarkar et al.

Abstract

A 65-year-old male pre-dialysis Turkish patient with diabetic nephropathy received a Cimino fistula of the left lower arm, which occluded before use within the following weeks after the operation. A polytetrafluorethylene (PTFE) loop was created at the left forearm. The first sessions of dialysis were successful; however, 2 weeks after starting dialysis using unfractionated heparin, the loop occluded. Platelet count dropped at this time, but not significantly. As thrombectomy of the loop was unsuccessful, a new PTFE loop at the left upper arm was created. After 2 months without any complications, the PTFE loop occluded again. A loop thrombectomy with revision of the protheto-venous anastomosis was performed initially and after 5 days, as the loop failed again. During both revisions, intraoperative angiography showed no stenosis of the central venous system draining of the left upper limb, and blood flow was well >600 mL/min. As there was no personal or family history of former thrombotic events, no examination for thrombophilic disorders was conducted at this time. Since the loop failed again after 8 days, a brachiocephalic fistula at the right arm was built. As recurrent clotting complications of the Shaldon catheters were recognized during dialysis, a tunnelled-cuffed catheter on the left side was applied to provide dialysis access until complete maturation of the fistula. In the further course, the tunnelled cuffed catheter had to be changed two times due to clotting complications and remained open only after blocking with urokinase. Platelet count did not drop significantly during each event (Figure 1). Laboratory testing for thrombophilia risk factors was performed (Table 1). Abnormal findings included heterozygosity for the prothrombin G20210A mutation, an increased level of von Willebrand factor (vWF) (ristocetin cofactor activity: 289%; vWF antigen: 348%) and elevated plasma factor VIII coagulant activity (273%). A test for lupus anticoagulants was only weakly positive, and cardiolipin antibodies could not be detected. As there was no significant drop in platelet count and the diagnosed thrombophilias were sufficient to explain the recurrent thromboembolic events, no investigation for heparin induced thrombocytopenia antibodies (HIT antibodies) was conducted, and an anticoagulation with phenprocoumon was started. Overlapping, a full anticoagulation with certoparin adapted to body weight was given, until a stable international normalized ratio (INR) within the range of 2–3 was achieved. Dialysis was conducted with unfractionated heparin. Despite sufficient anticoagulation, recurrent clotting complications, especially recurrent thrombotic occlusion of the dialysis machine lines and dialyser, occurred during dialysis. Hence, we conducted a heparin-induced platelet aggregation assay (HIPA), which detected a heparin-dependent activation of donor platelets. Further dialysis was performed with danaparoid (initial dose of 3750 units). Further dosing had to be adapted according to the anti-Xa level. No more thrombotic events occurred from that point, and the fistula was successfully used after 8-week maturation period.