Negative impact of dextran in organ culture media for pre-stripped tissue preservation on DMEK (Descemet membrane endothelial keratoplasty) outcome.

PURPOSE: To assess the morphological and functional outcomes of Descemet membrane endothelial keratoplasty (DMEK) performed with pre-stripped tissue preserved in organ culture medium containing dextran compared to tissue preserved in dextran-free medium.

METHODS

In this retrospective study, we reviewed the clinical records of 103 patients who underwent DMEK surgery with pre-stripped tissue in our department between June 2015 and September 2016. The endothelium-Descemet membrane layer was preserved in organ culture medium for a maximum of 48 h for all patients. For group 1, 49 endothelium-Descemet membrane (EDM) were stripped and preserved in medium 1 (dextran-free organ culture medium), while 54 EDM were stripped and preserved in medium 2 (organ culture medium supplemented with 6% dextran T-500) for group 2. Outcome measures included best-corrected visual acuity (BCVA), central corneal thickness (CCT), and endothelial cell density (ECD) of all eyes in both groups at three consecutive postoperative time points: 2 weeks, 6 weeks, and 6 months postoperatively. We also compared the repeat keratoplasty rates between the groups.

RESULTS

Group 1 showed a statistically significant better BCVA compared to group 2 at each time point (p < 0.05). The percentage of grafts achieving 0.5 or better after 6 months in group 1 was 96% and in group 2, it was 66% (P < 0.001). CCT was significantly lower in group 1 compared to group 2 at 2 weeks and 6 months after surgery (p < 0.05). ECD was comparable between donor grafts before surgery but was significantly greater in groups 1 after 2 and 6 weeks (p < 0.05), but not after 6 months. Necessity for repeat keratoplasty (repeat DMEK, subsequent penetrating keratoplasty (PKP)) was significantly lower in group 1 (p < 0.05).

CONCLUSIONS

Pre-stripped tissue for DMEK preserved in dextran-free medium led to better visual recovery, thinner postoperative corneas, a higher endothelial cell density, and a lower rate of repeat keratoplasty, indicating that dextran has an unfavorable impact on the preservation of pre-stripped DMEK tissue.