Influence of ABO blood group on von Willebrand factor tests in healthy Saudi blood donors.

: Von Willebrand disease is a common bleeding disorder. The wide variation in von Willebrand factor (VWF) levels between and within normal individuals highlights the clinical challenge of defining its cutoff value. Although studies on the influence of ethnicity on ABO phenotypes and the levels of VWF have been carried out on different ethnicities, there is a lack of such data among Arab population. We aimed to evaluate the correlation of ABO phenotypes with all the parameters of the minimal test panel of VWF including VWF antigen, VWF activity using the ristocetin cofactor and the collagen binding activity assays, and factor VIII coagulant activity (VWF:Ag, VWF:RCo, VWF:CB and FVIII:C) tested in a normal Arab population, and to estimate ABO-specific normal reference range. Blood samples were collected from 87 healthy donors in Riyadh to determine levels of factor VIII and VWF panel between the various ABO phenotypes. The highest mean values of factor VIII : C (128 U/dl), VWF : Ag (125 U/dl), VWF : RCo (109 U/dl) and VWF : CB (91 U/dl) were observed with type AB and the lowest mean values of factor VIII : C (81 U/dl), VWF : Ag (85 U/dl), VWF : RCo (73 U/dl) and VWF : CB (70 U/dl) corresponded to type O. ABO phenotypes significantly influence plasma levels of VWF parameters in Arab nations as seen with other ethnicity. Hence, ABO-specific normal ranges of the minimal test panel of VWF and factor VIII : C are essential for the appropriate prediction of mild von Willebrand disease. Further study including a larger categorized sample size is required to generalize the test panel on the Arab population.

Long-term audit of the use of fresh frozen plasma in a university hospital.

OBJECTIVES: There is universal concern about the inappropriate use of fresh frozen plasma (FFP). This study aimed to determine the extent of the inappropriate use of FFP at a university hospital in KSA. METHODS: Medical records on the annual use of FFP were analysed from 1986 to 2007. Then, the results of the coagulation screening tests were extracted from the medical records of 531 consecutive patients in various departments of the hospital. RESULTS: As many as 68,480 FFP units were used during the 22 year study period. Consumption increased and then plateaued in 1995, but dropped dramatically by 30.9% and reached its lowest level in 2000. There was also a concomitant and overlapping drop in both FFP usage and the hospital mortality rate per patient admission. One-thousand-six-hundred-twenty FFP units were issued for 531 patients. Coagulation testing, before and after infusion, was adopted in almost all patients in the Department of Obstetrics and Gynaecology, in 90% of patients in the Department of Surgery and in approximately 70% of patients in other departments. CONCLUSIONS: Significant inappropriate use of FFP at our institute has been made evident by examining the remarkable drop in use following the universal "HIV scare" of the early 1990s. The resulting drop in the hospital mortality rate, accompanying the simultaneous drop in FFP use, reflects the benefits of resorting to the use of less blood therapy. Coagulation testing was used to a satisfactory extent. Transfusion audits and educational programs could result a better use of FFP.

The Levels of Tissue Factor Pathway Inhibitor in Sepsis Patients Receiving Prophylactic Enoxaparin.

OBJECTIVE: Sepsis syndrome is usually accompanied by activation of blood coagulation mechanisms. Earlier studies found deficiencies of the 3 main natural anticoagulants, antithrombin, protein C, and protein S. However, none of these inhibitors block tissue factor, the prime trigger of coagulation during sepsis that is controlled specifically by the tissue factor pathway inhibitor (TFPI). The aim of this study was to characterize the fluctuations in the levels of natural anticoagulants, particularly TFPI, in the course of sepsis and to find out their association with the anticoagulant action of the low-molecular-weight heparin enoxaparin. MATERIALS AND METHODS: We studied 51 consecutive patients with sepsis. Blood samples were collected from patients at baseline (0 h) and at 4, 12, and 24 h after enoxaparin administration. The following assays were undertaken using commercial kits: activated partial thromboplastin time, prothrombin time, thrombin time, total and free TFPI, protein C and protein S, antithrombin, fibrinogen, and anti-factor Xa. RESULTS: Before enoxaparin administration, there was significant prolongation of the prothrombin time and activated partial thromboplastin time, and this remained the case in the 3 subsequent samples. There was marked reduction in the levels of antithrombin, protein C, and total and free protein S to below control values throughout the study. In contrast, plasma levels of both total and free TFPI were markedly elevated and increased after enoxaparin therapy. Anti-factor Xa levels were within the therapeutic range throughout. There was no difference in TFPI levels between those patients who died and those who survived. CONCLUSION: Sepsis triggered marked release of TFPI from endothelial cells. This persisted and was increased further following the administration of enoxaparin. In contrast, there was marked consumption of the natural coagulation inhibitors antithrombin, protein C, and protein S. These results go some way towards explaining why the therapeutic use of recombinant TFPI fails to correct sepsis-associated coagulopathy.

Bemiparin, an effective and safe low molecular weight heparin: a review.

Bemiparin is a low molecular weight heparin (LMWH) indicated for the acute treatment of deep vein thrombosis with or without pulmonary embolism, for the prophylaxis of venous thromboembolism in surgical and non-surgical patients and for the prevention of clotting in the extracorporeal circuit during hemodialysis. Due to its excellent pharmacological profile-the second-generation LMWH with the lowest molecular weight, the longest half-life and the highest anti-Factor Xa/anti-Factor IIa activity ratio-it can be safely used in special categories of patients (children, elderly, patients with renal impairment and congestive heart failure). Several studies demonstrated its safety and efficacy, while cost analyses show the economic benefits of bemiparin treatment as compared to other heparins. Recent evidences suggested the application of bemiparin even in the management of diabetic foot ulcers. The aim of this narrative review was to evaluate literature according to results coming from studies involving bemiparin administration in various clinical conditions.