New risk factors and predictions of the development of retinal vein occlusion after cardiac surgeries with the use of artificial circulation

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Background. Cardiovascular diseases are one of the risk factors for the development of retinal vein occlusion (RVO). Cardiac interventions with artificial circulation (AC) can be associated with perioperative complications, including retinal vessel occlusion. The actual task of modern ophthalmology is to determine the frequency of retinal vessel occlusions, clinical features, risk factors, the role of markers of inflammation and endothelial dysfunction in RVO in patients with cardiovascular diseases after surgeries with artificial circulation. The purpose of the study was to investigate new risk factors and predict the development of retinal vein occlusions after cardiac surgeries using artificial circulation. Materials and methods. Three hundred and ninety-four patients (638 eyes) were under observation. Of them, 220 people (405 eyes) had cardiovascular diseases and underwent heart surgeries with the use of AC. In these patients, we determined the nature, frequency and features of the development and clinical course of RVO after cardiac surgery with AC in the early and late periods of observation (3 and 6 months). Also, a study was conducted of 174 patients (233 eyes) with cardiovascular diseases who underwent cardiac surgeries with AC, and the serum levels of markers of inflammation (IL-6 and IL-8) and endothelial dysfunction (VE-cadherin) were determined before and after operations depending on the time of RVO occurrence. The main group included 126 patients (137 eyes) who were diagnosed with occlusion of the central retinal vein (CRV) or its branches after surgery with AC; the comparison group — 43 patients (86 eyes) who did not have retinal vein occlusion during the entire observation period; the control group — 5 patients (10 eyes) who had the same degree and duration of the underlying disease, indications for surgery with AC, but were examined before the operation, and within 180 days after it, and did not have RVO. The patients were examined by an ophthalmologist 2, 7, 30, 60, 90 and 180 days after cardiac surgery. The content of IL-6, IL-8 and VE-cadherin in blood serum was determined by the enzyme immunoassay (Bender MedSystems, Austria). Statistical data were processed using the Statistica 10 program (StatSoft Inc., USA), regression analysis was performed with the help of the GLZ software package. Results. As a result of the research, it was found that the frequency of retinal vein occlusions after cardiac surgeries with the use of artificial circulation was 0.99 % on the 2nd day, 3.95 % on the 7th day, 10.2 % after 3 months, 1.4 % after 6 months. The conducted discriminant analysis showed that the type of occlusion was determined by age, lower visual acuity, and the order of occlusion of the CRV branches. An increase in the macular volume of the retina was also significant, reflecting the development of macular edema. The regression model for predicting the type of occlusion based on visual acuity, the order of occlusion of the CRV branches and age had a prediction accuracy of 82.5 %. Cardiac surgeries with the use of AC caused an increase in interleukin content in the early period (IL-6 on days 2 and 7, and IL-8 — up to day 30), while the content of VE-cadherin was slightly increased during almost the entire observation period. In the presence of RVO, IL-6 content was significantly higher at all stages of occlusion development, IL-8 content — up to 30 days, and VE-cadherin content — mostly after 7 days. Regression analysis showed that after 1–2 days, the occurrence of RVO was directly related to the content of IL-6 and IL-8 in the blood, on days 3–7 — to the content of only IL-8, on days 8–30 — to the content of all markers, and later — to the content of IL-6 and VE-cadherin. The prediction accuracy for the presence or absence of RVO in the corresponding term according to the calculated regression models is at least 78 % (p < 0.001), which proves the influence of markers on the development of RVO. Conclusions. The conducted study shows the importance of acute inflammation and endothelial dysfunction in the occurrence of RVO when using AC, which justifies the use of preventive measures in the early stages of limiting the activity of the inflammatory process, in the later stages — preventing the development of endothelial dysfunction.