Endothelial Morphometric Measures to Predict Endothelial Graft Failure After Penetrating Keratoplasty

Importance: Endothelial morphometric measures have potential value in predicting graft failure after penetrating keratoplasty. Objective: To determine whether preoperative and/or postoperative central morphometric measures (endothelial cell density [ECD], coefficient of variation [CV], and percentage of hexagonality [HEX]) and their postoperative changes are predictive of graft failure caused by endothelial decompensation after penetrating keratoplasty to treat a moderate-risk condition, principally Fuchs dystrophy or pseudophakic corneal edema. Design: In a subset of Cornea Donor Study participants with graft failure, a central reading center determined preoperative and postoperative ECD, CV, and HEX from available central endothelial specular images. Setting: Cornea Image Analysis Reading Center of the Specular Microscopy Ancillary Study. Participants: Eighteen patients with graft failure due to endothelial decompensation and 54 individuals matched for most donor and recipient measures at baseline whose grafts did not fail. Main Outcome Measure: Change in ECD, CV, and HEX values. Results: Preoperative ECD was not associated with graft failure (P=.43); however, a lower ECD at 6 months was predictive of subsequent failure (P=.004). Coefficient of variation at 6 months was not associated with graft failure in univariate (P=.91) or multivariate (P=.79) analyses. We found a suggestive trend of higher graft failure with lower HEX values at 6 months (P=.02) but not at the established statistical significance (P<.01). The most recent CV or HEX values, as time-dependent variables, were not associated with graft failure (P=.26 and P=.81, respectively). Endothelial cell density values decreased during follow-up, whereas CV and HEX appear to fluctuate without an apparent trend. Conclusions and Relevance: Endothelial cell density at 6 months after penetrating keratoplasty is predictive of graft failure, whereas CV and HEX appear to fluctuate postoperatively, possibly indicating an unstable endothelial population in clear and failing grafts. Trial Registration: clinicaltrials.gov Identifier: NCT00006411