Abstract

Introduction: taking into account the fact of not well specified data considering defects of von Willebrand’s factor (vWF) resulting in hemorrhagic diathesis especially after procedures or menstrual bleeding, we decided to assess the activity of this factor, in a group of young and healthy people. Aim of the study. Assessment of the incidence of decreased activity of vWF based on the examination of ristocetin cofactor activity in the serum. Material and methods. The study involved 63 healthy volunteers (mean age 22.4 ±1.3) among them 45 female students (mean age 22.3±1.52) and 18 male students (mean age 22.7±0.5) of Medical University of Gdansk. In all subjects, anamnesis was taken on the basis of prepared questionnaires with special attention to family history of hemorrhagic diathesis. All subjects not physically predisposed and/or taking drugs among others anti-platelet and anti-aggregation ones were excluded from the study. After slow defrosting of the serum at the temperature of 37°C, activity of ristocetin cofactor was assessed by means of the coagulometric analyzer Behring Coagulation System (BSC) with the use of Dade-Behring reagents set strictly following the producer’s orders. Activated partial thromboplastin time (APTT) and prothrombine time were assessed by means of the immunoenzymatic ELISA test with the use of Behring testing sets. All the above mentioned examinations were performed in the Coagulation Laboratory of our Department. Blood morphology was assessed in the Central Laboratory of the Hospital. Activity of vWF was given in percentage of the normal value which in healthy subjects ranges from 50 to 150% of the norm and corresponds to 50 – 150 IU/dl. The obtained results were analyzed statistically counting their mean arithmetical values and standard deviation according to suitable equations.

Results: in the studied group, decreased activity of vWF (≤40%) was stated in 7 subjects – 3 women and 4 men. Two female students with decreased activity of this factor presented with significant menstrual bleeding lasting for about 7 days and in one of them decreased concentration of hemoglobin was stated. In the third female student menstruation bleeding was of medium intensity lasting about 5 days. APTT in the mentioned above students was within the normal range of values. APTT is prolonged only in persons with significantly decreased activities of factor VIII and it mainly considers vW disease type III. Also family history regarding hemorrhagic diathesis in these three students was negative which correlates with the literature. In 4 male students with decreased activity of vWF, no symptoms of diathesis were observed and family history was negative, too. However, in the coagulation system, a slight prolongation of APTT was stated. Blood morphology results did not show any deviation from normal values. Family anamnesis towards hemorrhagic diathesis of the examined subjects was positive in 9 out of 45 female students, none of them presented with decreased activity of vWF. Abundant menstruation bleeding was stated in 10 out of 45 girls, two of them had decreased activity of vWF, the other 8 did not show any deviation from the examined parameters. Percentage of the decreased activities of vWF in the examined group was very high (11.1%) what is discordant with the data from literature and Working Group of Hemostatic Disorders of the PTHiT which may be due to a small group of the examined subjects. According to this, a larger group of healthy young individuals should be examined for activity and concentration of vWF. Results of such analysis might indicate a more reliable way of screening towards vW disease. Conclusions: 1. In the examined group of the students, decreased activity of vWF was stated in 7 (11.1%) subjects. 2. Mean concentrations of vWF activity and other conducted examinations stayed within the normal range of values in the whole examined group. 3. The study should still be continued in a larger group of people.