Researchers identified factors related to graft rejection after Descemet stripping automated endothelial keratoplasty (DSAEK) in the Cornea Preservation Time Study (CPTS).
Study design
In this multicenter trial, 70 surgeons across 40 sites performed DSAEK on a total of 1,090 patients (1,330 eyes). Eyes with primary endothelial dysfunction, Fuchs endothelial corneal dystrophy or pseudophakic/aphakic corneal edema (PACE) were randomized to receive a donor cornea preserved for either 0 to 7 days (n=675) or 8 to 14 days (n=655). Patients were followed for at least 36 months following surgery, with a standardized reading center for endothelial cell density (ECD) analysis. A standardized graft rejection definition was used to categorize mild, severe or probable rejection episodes.
Outcomes
The cumulative probability of a definitive graft rejection episode over 3 years was 3.6%. Forty-four patients experienced 1 or more definite rejection episodes (4%) during the follow-up period; 22 episodes were mild and 20 were severe. Age was the only variable associated with an increased risk of rejection, with a hazard ratio of 0.53 with each increasing decade of age. None of the remaining 25 factors—including donor age, recipient gender, recipient race or recent prior immunizations—were significantly associated with rejection. Twelve of the eyes with definite rejection subsequently failed, but the rest cleared with treatment.
Among the clear grafts, greater endothelial cell loss was observed in eyes that experienced a rejection compared with those that lacked a history of rejection episodes (48% vs 38%; P=0.03).
Limitations
The study is limited by an overall small rate of rejection which might have restricted the ability to detect significant differences among some factors. The exclusion criteria were relatively strict and eliminated more complex PACE eyes and those with advanced glaucoma. Surgical technique and medical management of rejection were not standardized but were left to individual practitioners and may have introduced variability.
Clinical significance
This report from the CPTS further elucidates the low rate of rejection among DSAEK eyes. It also highlights the lack of risk factors associated with rejection, such as recent immunization, which could affect postoperative management. Since younger age was the only statically significant risk factor, surgeons could consider more aggressive and/or prolonged corticosteroid treatment in this group.