Diabetic, nondiabetic donor grafts yield similar failure rates after DSAEK, PK

Further study is needed to gauge the effect of donor diabetes on graft survival rates for each endothelial keratoplasty.

Issue: May 10, 2015

Corneal grafts from diabetic and nondiabetic donors had similar failure rates after two types of corneal transplantation surgery, a study found.

Perspective from David R. Hardten, MD

Further study is needed to determine whether diabetic donor tissue results in different graft failure rates after Descemet’s stripping automated endothelial keratoplasty compared with penetrating keratoplasty.

Mark A. Greiner

“To our knowledge, our study is the first to examine the effect of donor diabetes on DSAEK outcomes,” Mark A. Greiner, MD, the corresponding author, told Ocular Surgery News. “However, the number of diabetic graft failures in our sample was too small to support statistical analysis of the effect of donor diabetes on graft survival within each keratoplasty type.”

Diabetes can result in tissue damage because of oxidative stress from increased free radical production and reduced antioxidant levels. Chronic hyperglycemia can cause non-enzymatic glycosylation of proteins and development of advanced glycation end-products that may lead to cross-linking between molecules and alter protein function, Greiner said.

Diabetes can also cause a variety of morphologic and functional changes to the corneal endothelium, such as decreased cell density, decreased cell hexagonality, increased variation in cell size, increased central corneal thickness, increased endothelial permeability to fluorescein and increased corneal autofluorescence.

“These changes seem to be more pronounced with increasing duration of diabetes mellitus,” Greiner said. “In addition, patients with diabetes mellitus are more susceptible to endothelial dysfunction and corneal edema after both anterior segment and posterior segment intraocular surgery compared with nondiabetic controls.”

Patients and methods

The retrospective study, published in Cornea, included 183 eyes of 161 patients.

The analysis included eyes that were pseudophakic at the time of transplantation or underwent transplantation combined with cataract surgery and posterior chamber IOL implantation.

Eyes with previous corneal transplantation or postoperative endophthalmitis were excluded.

DSAEK was performed in 136 eyes, and PK was performed in 47 eyes; 24 grafts (13.1%) were from diabetic donors.

The primary outcome measure was graft failure. The median postoperative follow-up period was 64.5 months.

Greiner said that diabetic donor tissue does not require specialized techniques for graft harvesting, handling or processing in DSAEK or PK.

“However, this may not apply to tissue prepared for [Descemet’s membrane endothelial keratoplasty],” Greiner said. In a previous study comparing graft preparation of diabetic and nondiabetic tissue for DMEK, Greiner and colleagues found that tissue from diabetic donors had a tear rate of 15.3% during preparation.

Results and observations

There were four cases of graft failure (16.7%) among the 24 cases involving diabetic donor tissue; three failures occurred after DSAEK, and one occurred after PK.

Among 159 cases using nondiabetic donor tissue, there were 18 cases of graft failure (11.3%); 12 failures occurred after DSAEK, and six occurred after PK.

The risk of graft failure was similar in all cases using diabetic donor tissue or nondiabetic donor tissue, regardless of transplantation method.

“Because we did not analyze endothelial cell density, percent hexagonality, coefficient of variation, death-to-preservation or preservation-to-surgery data in this series, we were unable to detect any differences in donor tissue characteristics between diabetic and nondiabetic donor tissues,” Greiner said.

The DSAEK group had a significantly higher prevalence of glaucoma than the PK group (P = .009). However, significantly more eyes in the PK group underwent concurrent glaucoma surgery and corneal transplantation (P = .016).

Currently, there are no contraindications for the use of diabetic donor tissue for DSAEK or PK, Greiner said.

“However, there is a need for a large prospective multicenter investigation on this topic given the increasing prevalence of diabetes mellitus in the donor pool and growth in endothelial keratoplasty cases, with better characterization of diabetes severity in grafted donor tissue and graft recipients, and specified postoperative measurements of endothelial cell density,” he said. – by Matt Hasson

References:

Greiner MA, et al. Cornea. 2014:doi:10.1097/ICO.0000000000000262.
Vislisel JM, at al. Cornea. 2015;doi:10.1097/ICO.0000000000000378.

For more information:

Mark A. Greiner, MD, can be reached at Department of Ophthalmology and Visual Sciences, University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, IA 52242; email: mark-greiner@uiowa.edu.
Disclosure: Greiner reports no relevant financial disclosures.

Perspective

David R. Hardten, MD

This study starts discussion about a very important topic, that of using diabetic corneal tissue for transplantation. With the growing rates of diabetes in the population and the increasing needs for corneal transplant tissue, this is a question that needs to be answered. This study starts that discussion and points out the importance of a randomized controlled trial for answering this question. The Diabetic Endothelial Keratoplasty Study now being organized will hopefully shed important information concerning this topic as data become available over the next several years.

David R. Hardten, MD

OSN Cornea/External Disease Section Editor

Disclosures: Hardten reports no relevant financial disclosures.