Risks factors for graft preparation failure in DMEK
Reviewed by Magdalena Popiela

Diabetes mellitus (DM) makes it more difficult to prepare descemet membrane epithelial keratoplasty (DMEK) grafts due to the ‘stickiness’ of Descemet’s membrane. This retrospective study examined a classification system, where donors were scored points according to their DM related risk factors. The score was evaluated to check if it can stratify the risk of tissue preparation failure. Presence of DM, hypertension or BMI > 30kg/m2 each were awarded one point. Two points each were scored if duration of DM was longer than 10 years, DM required insulin treatment or the donor had any of DM related co-morbidities; retinopathy, neuropathy, nephropathy or limb amputation. This scoring system was examined retrospectively on 125 tissue donors prepared by trained technicians. Eighteen procedures failed, representing an overall 14.4% failure rate. Scores one to three were deemed low risk for graft preparation failure (three graft preparation failures and 62 successful preparations) whereas scores four and five were ‘high risk’ with 15 graft failures and 45 successful preparations. This difference was statistically significant. The score ranking of five was found to be statistically significant with respect to the odds of preparation failure rates and showed the most frequent occurrence of graft preparation failures (30.6%). This study proposes a risk scoring system, which can be used prior to deciding which donor grafts can be used for DMEK. Despite the small numbers it suggests that the higher number of DM related co-morbidities might adversely affect the success of DMEK tissue preparation. Tissue from donors with high scores should be used for corneal procedures other than DMEK. 

Descemet membrane endothelial keratoplasty (DMEK) tissue preparation: a donor diabetes mellitus categorical risk stratification scale for assessing tissue suitability and reducing tissue loss.
Williams R, Mayko Z, Friend DJ, et al.
CORNEA
2016;35(7):927-31.