Capillary microscopic and rheological dimensions for the diagnosis of von Willebrand disease in comparison to other haemorrhagic diatheses

It is known that angiodysplasia influence macrocirculation as well as micro circulation in patients with vWD. In the present study it was examined if i ntravital capillary microscopic dimensions (morphologic and dynamic) in ski n (nailfold) in combination with theologic parameters could give indication s for the presence of vWD in patients with haemorrhagic diathesis. Patients with vWD (n = 100; 92 type 1: definite type 1:78 and possible type 1:14; 8 type 2A) have in comparison to patients with other haemorrhagic di athesis [thrombocytopathy (n = 122), thrombocytopenia (n = 101), severe hae mophilia A (n = 50) and severe haemophilia B (n = 20), congenital dysfibrin ogenaemia (n = 22), oral anticoagulation with phenprocoumone (n = 112)] and to apparently healthy subjects (n = 100) a significantly increased capilla ry torquation (median index: 3.5), a venolar and an arteriolar capillary di latation (median: 16.5 mum; median: 15.1 mum) and the highest part of micro scopic bleedings (extravasates) with 40% in the video capillary microscopy as morphological changes. Only the congenital dysfibrinogenaemia appears wi th a larger dilatation in venolar capillaries (median: 14.5 mum). Microscop ic bleedings are much less common in other haemorrhagic diatheses with a fr equency between 4% and 13%. In the vWD a significantly reduced duration of reactive hyperaemia (median: 150 sec). This is the only dynamic change that can be taken as a possible hint for a loss of flexibility within the precapillary vessels. A significa ntly reduced plasma viscosity (<1.25. mPas) is typical for the vWD due to t he increase of the shear-stress in blood plasma because of the reduction of vWF-activities. Changes of the capillary morphology (dilatation, extravasa tes, capillary torquation) and the hypoplasmaviscosity are most sensitive f or the vWD (75%, 65%, 40%, 80%) with a fairly high specifity (up to 93%) an d a positive predictive value of 99%. As a conclusion it seems reasonable to discuss the introduction of video ca pillary microscopy as a screening test for haemostasiological and angiologi cal centers.