Risk of corneal transplant rejection significantly reduced with Descemet's membrane endothelial keratoplasty

Purpose: To evaluate the relative risk of immunologic rejection episode in patients who underwent Descemet's membrane endothelial keratoplasty (DMEK), Descemet's stripping endothelial keratoplasty (DSEK), and penetrating keratoplasty (PK).

Design: Comparative case series.

Participants: One hundred forty-one eyes treated with DMEK at Price Vision Group, Indianapolis, Indiana.

Methods: The patients in the DMEK group were compared retrospectively with cohorts of DSEK (n = 598) and PK (n = 30) patients treated at the same center, with similar demographics, follow-up duration, and indications for surgery. The postoperative steroid regimen and rejection criteria were identical in the 3 groups. Kaplan-Meier survival analysis, which takes varying length of follow-up into consideration, was performed to determine the cumulative probability of a rejection episode 1 and 2 years after surgery. Proportional hazards analysis was used to determine the relative risk of rejection episodes between the 3 groups. P<0.05 was considered significant and calculated using the log-rank test.

Main outcome measures: Rejection-free survival and cumulative probability of a rejection episode.

Results: The mean recipient age was 66 years (56% females and 94% Caucasian) and median follow-up duration was 13 months (range, 3-40) in the DMEK group. Fuchs' dystrophy was the most common indication for surgery (n = 127; 90%) followed by pseudophakic bullous keratopathy (n = 4; 4%) and regrafts (n = 9; 6.4%). Only 1 patient (0.7%) had a documented rejection episode in the DMEK group compared with 54 (9%) in the DSEK and 5 (17%) in the PK group. The Kaplan-Meier cumulative probability of a rejection episode at 1 and 2 years was 1% and 1%, respectively, for DMEK; 8% and 12%, respectively, for DSEK; and 14% and 18%, respectively, for PK. This was a highly significant difference (P = 0.004). The DMEK eyes had a 15 times lesser risk of experiencing a rejection episode than DSEK eyes (95% confidence limit [CL], 2.0-111; P = 0.008) and 20 times lower risk than PK eyes (95% CL, 2.4-166; P = 0.006).

Conclusions: Patients undergoing DMEK had a significantly reduced risk of experiencing a rejection episode within 2 years after surgery compared with DSEK and PK performed for similar indications using the same corticosteroid regimen.