Outcomes of repeat penetrating keratoplasty and risk factors for graft failure

Purpose. To compare repeat penetrating keratoplasty (PKP) with primary PKP with respect to patient characteristics, survival rates, and risk factors for graft failure. Methods. Retrospective, consecutive, noncomparative case series of 116 patients who underwent repeat PKP and who were identified from a cohort of 696 PKPs performed by one surgeon over a 7.5-year period. Results. Compared with patients who underwent primary PKP, regraft patients were 5 years older, had a higher rate of peripheral anterior synechiae (PAS), were more likely to require intraocular pressure (IOP)-lowering medications prior to surgery, were more likely to develop postoperative corneal neovascularization, were less likely to be phakic, and were more likely to undergo PKP in conjunction with a lens procedure. There was no difference between the two groups with respect to the distribution of original diagnoses leading to PKP and the rate of graft rejection. Two- and 5-year survival rates for repeat PKP were 63.9% and 45.6%, respectively. In a multivariate analysis, the original diagnosis leading to corneal transplantation, the presence of preoperative PAS, intraoperative anterior vitrectomy, and postoperative corneal neovascularization were identified as risk factors for graft failure in patients undergoing a regraft. Conclusions. Patients undergoing PKP for the first and second time share common risk factors for graft failure, namely, the original diagnosis leading to corneal transplantation, the presence of preoperative PAS, and the occurrence of postoperative corneal neovascularization. The difference in graft survival rates between the two groups can be partially explained on the basis of higher rates of the latter two risk factors among regrafts.