The effect of cornea preservation time on Descemet membrane endothelial keratoplasty outcomes.

Abstract

Purpose : The average preservation time (PT) of donor corneas at Hôpital Maisonneuve-Rosemont (HMR) is 8 to 9 days according to Héma-Québec, but corneas are frequently used up to 14 days. In the United States the vast majority of corneas are stored fewer than 8 days as many surgeons refuse donor tissue stored for longer. Our overall goal is to determine if a longer PT has an impact on the outcome of Descemet membrane endothelial keratoplasty (DMEK) cornea transplants.

Methods : This ambispective observational study involves 265 eyes of 219 patients who consecutively underwent DMEK at HMR between April 2015 and July 2018. Eyes were divided in groups: Group 1: Donor cornea preserved ≤7 days, and Group 2: >7 to 14 days. The primary outcome was central endothelial cell density (ECD) at 12 months post-DMEK, and secondary outcome parameters were graft failure and rebubbling rate.

Results : The 12 months follow-up will be completed for all patients in July 2019. Preliminary results on 36 eyes of 32 patients (Group 1: n=17 and Group 2: n=19). The mean age at surgery was 68 years (range: 48-88 years; 50.2% men). Mean follow-up time was 18.3 months. Mean (±SD) preoperative donor ECD was 2697±337 cells/mm² in Group 1 and 2840±319 cells/mm² in Group 2. At 1 year, mean ECD decreased to 1261±559 cells/mm² and 1190±451 cells/mm², respectively (mean difference, 71 cells/mm²; 95% CI [-271.65 to 413.65]; p= 0.68). This represented an endothelial cell loss of 53±18% in Group 1 and 58±17% in Group 2 (mean difference 5; 95% CI [-6.86 to 16.86]; p= 0.49). 65% of central ECD in Group 1 were over 1000 cells/mm² compared to 53% in Group 2. Rebubbling and failure rates were 29% and 0% in Group 1 and 26% and 11% in Group 2. Mean delay from death to preservation was 11.56±5.55 hours in Group 1 and 12.49±6.18 hours in Group 2 (mean difference 0.93; 95% CI [-3.07 to 4.93]; p= 0.64). Mean delay from stripping to surgery was 2±1.13 days (range: 0-4 days) for Group 1, and 2±1.57 days (range: 0-6 days) for Group 2 (mean difference 0.24; 95% CI [-0.54 to 1.02]; p= 0.59).

Conclusions : Preliminary results indicate that PT did not significantly affect DMEK outcomes. Follow-up on a larger sample size will be presented. If long PTs negatively impact DMEK this will affect eye bank storage worldwide. Conversely, safe use of longer PTs will allow for an increased DMEK donor pool, reducing waiting lists and facilitating tissue access.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.