[Computer-assisted in vivo study of capillary permeability].

Terminal circulation can be studied in vivo using capillaroscopy. This paper presents the results of systematic investigations of capillary permeability (KPU) in the nailfold. In addition to the morphology of capillary loops, we investigated the transcapillary passage and interstitial distribution of sodium fluorescein (Na-flu) in healthy persons (42) and in patients suffering from functional microangiopathies (17) or organic vascular disease (58). The effects of various therapeutic measures on the microcirculation were also studied. First, dynamic processes at the capillary loops were recorded on a video system. The second step consisted of quantification of the pericapillary light intensities (FLI) at predetermined times using a computerized video-densitometer. The measured variables, i.e. maximal interstitial FLI, diameter of the juxtacapillary halo (IK-H) and distance between the intracapillary column of red cells and the interstitial peak of FLI, provided information about the permeability of the capillaries and the interstitial diffusion of Na-flu. In healthy subjects, the interstitial FLI reached its highest values 10 sec after the appearance of Na-flu in the capillary loop, the distance between the peak of FLI and the intracapillary column of erythrocytes increased continuously over a period of 2 min, whereas the diameter of the IK-H reached a constant value after 20 sec. In patients suffering from functional microangiopathy, an increased pericapillary FLI as well as an enlarged juxtacapillary zone with elevated Na-flu concentrations could be established as objective criteria in addition to the already known alterations of the morphology of the capillary loops. Similar observations, but of much greater extent, were made in patients suffering from microvessels disease associated with collagen disease. The regional variation in the pericapillary FLI supports the assumption that morphological changes are present in these patients. KPU in patients suffering from organic macroangiopathy revealed no changes in comparison to healthy persons. The effects of conventional therapy in patients with reduced peripheral arterial perfusion on the parameters measured by KPU were of variable magnitude. The increase in trans-capillary leakage and interstitial dispersion of Na-flu was significant during systemic fibrinolysis and during the intra-arterial application of PGE1. The changes in the measured parameters were considerably smaller during therapy with phenprocoumarol and heparin, whereas treatment with inhibitors of platelet aggregation left the results of KPU unchanged.(ABSTRACT TRUNCATED AT 400 WORDS)