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

ABSTRACT

It is known that angiodysplasia influence macrocirculation as well as microcirculation in patients with vWD. In the present study it was examined if intravital capillary microscopic dimensions (morphologic and dynamic) in skin (nailfold) in combination with rheologic parameters could give indications for the presence of vWD in patients with haemorrhagic diathesis. Patients with vWD (n = 100; 92 type 1 definite type 178 and possible type 114 8 type 2A) have in comparison to patients with other haemorrhagic diathesis [thrombocytopathy (n = 122), thrombocytopenia (n = 101). severe haemophilia A (n = 50) and severe haemophilia B (n = 20). congenital dysfibrinogenaemia (n = 22), oral anticoagulation with phenprocoumone (n = 112)] and to apparently healthy subjects (n = 100) a significantly increased capillary torquation (median index 3.5), a venolar and an arteriolar capillary dilatation (median 16.5 microm; median 15.1 microm) and the highest part of microscopic bleedings (extravasates) with 40% in the video capillary microscopy as morphological changes. Only the congenital dysfibrinogenaemia appears with a larger dilatation in venolar capillaries (median 14.5 microm). Microscopic bleedings are much less common in other haemorrhagic diatheses with a frequency 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 significantly reduced plasma viscosity (< 1.25 mPas) is typical for the vWD due to the increase of the shear stress in blood plasma because of the reduction of vWF-activities. Changes of the capillary morphology (dilatation, extravasates, capillary torquation) and the hypoplasmaviscosity are most sensitive for the vWD (75%, 65%, 40%, 80%) with a fairly high specifity (up to 93%) and a positive predictive value of 99%. As a conclusion it seems reasonable to discuss the introduction of video capillary microscopy as a screening test for haemostasiological and angiological centers.