Evaluation of the morphofunctional state of peripheral blood platelets in sepsis

Background: Sepsis is a severe life-threatening condition characterized by combined dysfunction of the inner organs and systems and by dysregulation of the platelet and coagulation compartments of hemostasis, in particular.

Aim: To assess the character of abnormalities in morphofunctional state of platelets in the pathophysiology of sepsis and the multiple organ failure syndrome by means of coherent interference microscopy.

Materials and methods: This single center, prospective, observational study included 78 hospitalized patients with abdominal sepsis; in 40 of them, the syndrome of multiple organ failure was diagnosed. The causes of sepsis were peritonitis of various etiologies in 55 patients, acute necrotic pancreatitis with suppurative and septic complications in 23. The control group included 25 physically healthy subjects. Coherent interference microscopy was used for vital assessment of the platelet morphofunctional state, with simultaneous analysis of routine coagulogram and platelet aggregation parameters.

Results: The group of patients with sepsis (n = 38) had higher fbrinogen levels, compared to that in the control (4.5 ± 1 g/L, p = 0.0001), with mild thrombocytopenia (238 ± 12 × 109/L, p = 0.0001). Platelet aggregation was also increased (48 ± 3%, p = 0.0001). Assessment of circulating platelets by coherent interference microscopy showed a progressive increase of the mean populational morphodensitometrical parameters, such as the diameter (p = 0.0002), perimeter (p < 0.0001), and area (p = 0.0002), as well as a decrease in mean values of the phase height (p = 0.0002) and volume (p = 0.0002). There was an increase in the proportion of activated cells to 41% (vs. 33% in healthy control) and the proportion of degenerative cells up to 8%. The patients with severe sepsis complicated by multiple organ failure (n = 40), compared to the control ones, demonstrated exhausted of compensatory mechanisms with the development of consumption coagulopathy: prolonged activated partial thromboplastin time (57 ± 2 s, p = 0.0001), increased prothrombin index (117 ± 4, p = 0.0025), decreased fbrinogen level (1.6 ± 2 g/L, p = 0.0001) and platelet counts (110 ± 9 × 109/L, p = 0.0001), and their lower aggregation (24 ± 3%, p = 0.0001). According to the results of the coherent phase microscopy, the types of the morphodensitometrical abnormalities were similar to that in the main group, albeit they were more signifcant. The proportion of the activated cells was 43%, while that of the degenerated and functionally incompetent platelets, 15%. There were signifcant correlations between the morphodensitometrical parameters of the platelets and basic parameters of their aggregation induced by adenosine diphosphate and collagen.