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Abstract

PURPOSE: This study aimed to evaluate early postoperative changes in retinal microvasculature in patients undergoing cardiopulmonary bypass surgery by comparing preoperative and postoperative measurements of superficial capillary plexus and, deep capillary plexus vessel density, foveal avascular zone area using optical coherence tomography angiography (OCT-A).
METHODS: This prospective longitudinal study included 38 patients, undergoing cardiopulmonary bypass surgery. Each patient served as their own control optical coherence tomography angiography imaging was performed at four time points: 3 days preoperatively and at postoperative week 1, week 2, and month 1. Vessel densities in the superficial capillary plexus and deep capillary plexuses and the foveal avascular zone area were measured and analyzed. Depending on data distribution repeated measures analysis of variance or the Friedman test was used for statistical analysis.
RESULTS: Data from all 38 patients were included in the analysis. A significant increase in overall superficial capillary plexus vessel density was observed following cardiopulmonary bypass surgery (p=0.008). In contrast, deep capillary plexus vessel density did not differ significantly between the preoperative and postoperative assessments. The foveal avascular zone area showed a significant increase at postoperative week 2 compared with baseline (p=0.016).
CONCLUSION: Cardiopulmonary bypass surgery may induce early retinal microvascular alterations, particularly in the superficial capillary plexus and foveal avascular zone. Optical coherence tomography angiography is a noninvasive and reproducible imaging modality that enables precise assessment of subtle retinal vascular changes after major cardiovascular surgery. These findings may contribute to postoperative monitoring and risk assessment in patients undergoing cardiopulmonary bypass.

Keywords: Cardiopulmonary bypass surgery; Extracorporeal circulation; Macular vessel density of the retina; Retina/blood supply; Foveal avascular zone; Optical coherence tomography angiography; Retinal microvasculature