Influence of dextran deswelling on graft preparation and clinical outcomes in DMEK

Abstract

Abstract To evaluate the influence of dextran-containing versus dextran-free organ culture media on graft preparation characteristics and postoperative outcomes following Descemet Membrane Endothelial Keratoplasty (DMEK). In this single-center retrospective comparative study, 31 organ-cultured corneoscleral donor rims obtained from the Eye Bank of the University Hospital of Cologne between 2018 and 2022 were analyzed. Donor age ranged from 52 to 74 years. Donor tissues were allocated to either dextran-containing organ culture medium (group A, n = 16) or dextran-free medium (group B, n = 15) according to logistical and surgical scheduling considerations. Intraoperative graft preparation characteristics were assessed using a standardized scoring system evaluating Descemet membrane splitting and stripping behavior, graft fragility, and central and peripheral attachment tendencies. Postoperative outcome parameters included Best Spectacle-Corrected Visual Acuity (BSCVA), central and peripheral corneal thickness (CCT and PCT), endothelial cell count (ECC), and re-bubbling rate over a follow-up period of 12 months after DMEK. All 31 DM-endothelium grafts were successfully prepared and transplanted for DMEK. No significant differences were observed between swollen and dextran-deswollen grafts regarding intraoperative preparation characteristics, including stripping behavior ( p = 0.722), graft fragility ( p = 0.433), peripheral attachment tendency ( p = 1.000), and central tearing tendency ( p = 0.484). Descemet membrane splitting behavior was also comparable between groups. At 12 months postoperatively, no significant differences were detected between groups regarding CCT (group A: 517.67 ± 15.10 µm vs. group B: 530.10 ± 24.92 µm; p = 0.189) or re-bubbling rate ( p = 0.704). A trend toward lower PCT was observed in group B (group A: 604.00 ± 21.67 µm vs. group B: 579.50 ± 36.12 µm; p = 0.063), accompanied by a trend toward higher ECC in group B (group A: 1387 ± 131 cells/mm 3 vs. group B: 1692 ± 242 cells/mm 3 ; p = 0.066). BSCVA at 12 months was significantly better in the dextran-free group (group A: 0.08 ± 0.38 logMAR vs. group B: 0.03 ± 0.13 logMAR; p = 0.032). Swollen and dextran-deswollen donor grafts demonstrated comparable intraoperative preparation characteristics and similar postoperative outcomes following DMEK. The slightly improved visual outcomes observed in the dextran-free group suggest that dextran supplementation during organ culture may not be necessary for DMEK graft preparation. Avoiding dextran may further reduce time and costs in corneal eye banking. Larger prospective studies are warranted to confirm these findings.