Influencing factors on chronic endothelial cell loss characterised in a homogeneous group of patients.

BACKGROUND/AIM Advanced donor age, long death to excision time interval, and factors related to organ culture can trigger unfavourable intracellular processes in the graft endothelium and contribute to chronic endothelial cell loss after penetrating keratoplasty. The aim of this study was to investigate factors influencing chronic endothelial cell loss in a homogeneous group of patients. METHODS 177 patients after first normal risk keratoplasties for keratoconus were retrospectively selected from the quality control database of our clinic. For 71 of them at least four central endothelial cell density values were documented in follow up. From these patients, only those 53 without any further intraocular procedures, without glaucoma, and without graft rejection were considered. A scatter plot of logarithmised endothelial cell density values against postoperative time was drawn for each patient. The slope of the regression line then equals the constant of decay in central endothelial cell density. The influence of donor age and storage time in organ culture on this index value of cell loss was investigated by means of linear regression analysis. RESULTS Mean loss of central endothelial cell density was 16.7% per year. Regression analysis revealed a statistically significant negative linear effect of both postmortem time (beta = -0.324; p = 0.014) and donor age (beta = -0.282; p = 0.036) and a trend for storage time in organ culture (beta = -0.195; p = 0.142) in a combined linear regression model. CONCLUSION Increased postmortem time and advanced donor age exert a significant negative effect on chronic endothelial cell loss. Storage time in organ culture seems to be third influencing factor. These negative influences may be reduced by compensating advanced donor age with minimised postmortem and storage time.