Early postoperative effects of cardiopulmonary bypass surgery on optic nerve head and peripapillary retinal structures: an OCT-A study

To quantitatively assess the early postoperative effects of cardiopulmonary bypass (CPB) surgery on optic nerve head (ONH) morphology, peripapillary retinal nerve fiber layer (PRNFL) thickness, and radial peripapillary capillary density (RPCD) utilizing optical coherence tomography angiography (OCT-A). A prospective observational study was conducted involving 40 eyes of 40 patients undergoing CPB surgery. Baseline (preoperative) measurements of ONH parameters, PRNFL thickness, and RPCD were acquired using OCT-A. Postoperative evaluations were performed at postoperative week 1, week 2, and month 1. Statistical analyses were performed using repeated measures analysis, with paired t-tests or Wilcoxon signed-rank tests applied for post hoc pairwise comparisons depending on data distribution. A statistically significant but transient increase in PRNFL thickness was observed at postoperative week 1 and week 2 (p < 0.05), which returned to baseline by the first month. No significant differences were detected between preoperative and postoperative measurements concerning RPCD, cup-to-disc ratio, rim area, disc area, or cup volume. CPB surgery was associated with early but reversible changes in the ONH and peripapillary retinal structures in this study. OCT-A may serve as a useful non-invasive tool in the assessment of these transient changes. Longer-term follow-up studies are necessary to determine the sustained and permanent ocular effects of CPB surgery.