Donor risk factors for graft failure in a 20-year study of penetrating keratoplasty

Objective: To determine donor risk factors for graft failure and late endothelial failure (LEF) 20 years after penetrating keratoplasty (PK). Methods: Prospective, observational study of 500 consecutive PKs performed by one surgeon. After excluding eyes undergoing second grafts, fellow eyes of bilateral cases, and patients who withdrew research authorization, 388 eyes (388 patients) were available for analysis. At specific intervals during 20 years of follow-up after PK, the central corneal endothelium was analyzed by specular microscopy and risk factors for graft failure and LEF were determined. Results: The 41 grafts examined at 20 years represented 22% of the available clear grafts. Mean (SD) donor endothelial cell loss since the preoperative examination was 74% (9%), with no change in endothelial cell density between 15 and 20 years (P=.93; 36 eyes). Eighty-three grafts were known to have failed, of which 26 were because of LEF. Transplant recipients with a diagnosis of keratoconus had a lower risk of graft failure (P=.03) and LEF (P≤.03) compared with those with endothelial dysfunction. Neither the method (McCarey-Kaufman or K-Sol media [n =275] or organ culture [n=113]) nor the length of donor preservation was associated with graft failure or LEF. Lower preoperative endothelial cell density (P=.02) and higher endothelial cell loss at 2 months (P=.004) increased the risk of LEF for a recipient diagnosis of endothelial dysfunction but not keratoconus. Conclusions: Recipient diagnosis is a risk factor for graft failure. The length of corneal preservation is not associated with graft failure or with LEF, but these results should be confirmed in a study in which donor corneas are preserved using current methods and with more complete follow-up.