Beth Ann Benetz

CWRU Dept of Ophthalmology & Visual Science; CIARC, Cleveland, Ohio, USA

Purpose: Examine the impact of preservation time (PT) with 2-8°C storage on DSAEK graft success and endothelial cell loss (ECL) along with over 50 other donor, recipient, DSAEK processing, operative and postoperative factors.

Methods: A double-masked, randomized clinical trial was conducted at 40 clinical sites (70 surgeons) and 23 eye banks in the USA. 1090 individuals (1330 eyes) underwent DSAEK for Fuchs’ dystrophy and PACE with random assignment of a donor cornea with a PT of 7 days or less (0-7d PT) or 8 to 14 days (8-14d PT) and followed for 3-5 years. Donor and patient characteristics, tissue preparation and surgical parameters, recipient and donor corneal stroma clarity, CCT, IOP, complications, and a reading center-determined ECD were collected. Proportional hazards and logistic regression models estimated risk ratios (RR) and 99% confidence intervals (CIs) for all factors associated with graft success and ECD by 3 years.

Results: The 3-year cumulative probability of graft success was 95.3% (0-7d PT) and 92.1% (8-14d PT) with non-inferiority not proven, driven by the 12-14 day group (89%). However, no difference in cumulative probability of graft success up to 11 days was noted along with cell loss by 3 years. Donors with diabetes (RR, 2.35; 99% CI, 1.03-5.33) and preop dx of PACE (RR, 3.59; 99% CI, 1.05-12.24) were associated with higher graft failure, as well as lower 3 years ECD. Increased pre-cut donor thickness was also associated with greater operative complications (for every 50 µm of donor corneal thickness pre-cut, operative complications increased odds by 40%), and graft detachments (OR: 1.13 [1.01, 1.27] per 25µm increase).

Conclusion: With comparable PT DSAEK outcomes up to 11 days, there are now evidence-based results providing greater flexibility in evaluation and distribution of hypothermically stored donor tissue domestically and internationally. The CPTS should influence surgeons to not be as concerned about the donor cell count as long it meets minimum standards and focus attention on reduction of operative complications. Specifics regarding donor diabetes severity and pre-cut tissue thickness on suitability for EK requires further study.