Effect of Six-Month Postoperative Endothelial Cell Density on Graft Survival after Descemet Membrane Endothelial Keratoplasty

Vasiliauskaitè I, Quilendrino R, Baydoun L, van Dijk K, Melles GRJ, Oellerich S

Abstract

PURPOSE To analyze if 6-month endothelial cell density (ECD) affects long-term ECD outcome and graft survival 5 years after Descemet membrane endothelial keratoplasty (DMEK) in eyes with Fuchs endothelial corneal dystrophy (FECD). DESIGN Retrospective cohort study. PARTICIPANTS A total of 585 DMEK eyes were included. The study group was divided into 4 groups based on 6-month ECD quartiles: group 1 (n~= 146) with 313 to 1245 cells/mm2, group 2 (n~= 148) with 1246 to 1610 cells/mm2, group 3 (n~= 145) with 1611 to 1938 cells/mm2, and group 4 (n~= 146) with 1939 to 2760 cells/mm2. Group 1 was further split into subgroups 1a (n~= 36) with 6-month ECD of $\leq$828 cells/mm2, 1b (n~= 37) with 829 to 1023 cells/mm2, 1c (n~= 37) with 1024 to 1140 cells/mm2, and 1d (n~= 36) 1141 to 1245 cells/mm2. METHODS Descemet membrane endothelial keratoplasty. MAIN OUTCOME MEASURES Long-term ECD, graft survival, and postoperative complication rates. RESULTS For group 1, 6-month ECD decreased from 951 ($\pm$233) cells/mm2 (n~= 146) to 735 ($\pm$216) cells/mm2 (n~= 99) at 5 years postoperatively. Group 1 graft survival probability was 0.95 (95{\%} confidence interval [CI], 0.91-0.99] at 5 years postoperatively, which was lower than for groups 2 to 4 (P~= 0.001). Five-year graft survival in subgroup 1a was 0.79 (95{\%} CI, 0.67-0.94), which was lower than in subgroups 1b to 1d (P~= 0.001). Preoperative ECD did not influence graft survival (P~= 0.400), and higher 6-month ECD values were associated with lower graft failure rates (hazard ratio, 0.994; 95{\%} CI, 0.99-1.00; P~= 0.001). CONCLUSIONS Six-month ECD is associated with DMEK graft survival. High early cell loss after DMEK negatively affects long-term ECD outcome and graft survival. Grafts in the lowest 6-month ECD subgroup ($\leq$828 cells/mm2) are at higher risk of failure within 5 years after DMEK. To ensure sufficiently high 6-month ECD, preoperative graft quality assessment should be optimized, and cellular stress induced to the graft should be minimized. Additionally, developing therapeutic options for the treatment of low postoperative ECD could further improve DMEK graft longevity.