February 04, 2016
3 min read
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Diabetic donor tissue viable for DMEK with proper surgeon training

Diabetic donors have higher graft preparation failure rates but similar survival and endothelial cell counts compared with non-diabetic donors.

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Special training in graft preparation is critical when using tissue from diabetic donors in Descemet’s membrane endothelial keratoplasty, a speaker said at the European Society of Cataract and Refractive Surgeons meeting in Barcelona.

Francis W. Price Jr., MD, OSN Cornea/External Disease Board Member, described challenges involved when using diabetic donor tissue in DMEK, Descemet’s stripping endothelial keratoplasty and penetrating keratoplasty.

“DMEK tissue preparations are more likely to fail if the donor had diabetes, but most diabetic donors can be prepared successfully if the people doing the preparations are well trained in how to do it,” Price said.

Diabetes is prevalent in the global population and will become more so in the coming decades, Price said.

“By 2030, we’re going to have higher rates of diabetes everywhere. The worst will probably be in India, where they’re projecting that about 80% of the population will be diabetic. So, this has a lot of implications for health issues as well as what we’re doing in the eye,” he said.

Francis W. Price Jr.

Eye bank and donor studies

Price said that diabetes affects the capillary basement membranes and may cause adhesion.

“The question is, does it cause changes in the Descemet’s cleavage planes? You can have very smooth cleavage planes that come off easily, or you can have rough ones that are more difficult to remove,” he said. “So, the two questions are, does diabetes lead to these changes in Descemet’s membrane? [With] horseshoe tears, with the membrane being more brittle, or with more adhesions? And if it doesn’t cause it, then why do diabetics have more adhesions?”

In a U.S. eye bank study conducted in 2013, 30% of cornea donors were diabetic. The Cornea Donor Study, conducted between 2000 and 2002, showed that 18% of donors were diabetic, Price said.

“Both of these numbers may be underestimates because it’s estimated that in the U.S. that about a quarter of the diabetics aren’t even diagnosed,” he said.

A study by Greiner and colleagues, published in Cornea in 2014, showed DMEK donor graft preparation failure rates for diabetic donors ranging from 10% to 25%; failure rates for non-diabetic donors ranged from 1% to 5%, Price said.

Another study, by Vianna and colleagues, published in the American Journal of Ophthalmology in 2015, showed a DMEK donor preparation graft failure rate of 5%.

“When they did multivariate analysis, they found that diabetes would lead to a sixfold increase, so to put that in perspective, a 2.2% failure rate when it was non-diabetics and 14% in diabetics. They also found a fourfold increase in failures with donor hyperlipidemia. That was multivariate analysis, so that was independent of diabetes,” Price said.

Ten-year data from the Cornea Donor Study published by Lass and colleagues in Ophthalmology in 2015 showed that PK failure rates at 10 years did not vary with donor diabetic status. In addition, diabetic status did not affect endothelial cell loss in PK. “It was high in both groups,” Price said.

A single-center series on Descemet’s stripping automated endothelial keratoplasty and PK published by Vislisel and colleagues in Cornea in 2015 showed that donor diabetes did not affect graft survival, Price said.

Consecutive series of DMEK cases

A study of 1,310 consecutive DMEK cases performed at Price Vision Group in Indianapolis showed graft preparation failure rates of 6.6% among diabetic donors and 0.7% among non-diabetic donors.

Two-year graft survival rates were 94% among diabetic donors and 96% among non-diabetic donors, which was not a significant difference.

Endothelial cell counts at 2 years were similar for diabetic and non-diabetic donors, Price said.

“The limitation is that the eye banks have used a very simplistic method to diagnose diabetes. It’s a limited history they do with the medical records and a little bit with the family. There’s little to no information on the type of treatment, whether it’s insulin or some other type, the duration of diabetes or the level of glycemic control,” Price said.

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He offered further pearls on graft preparation.

“We don’t think you can exclude diabetic donors for DMEK preps. You can have the eye bank take the risk of doing the donor preps, or the surgeon can take it,” Price said. “But if the surgeon does it, I think the eye bank has to supply him with another donor if the prep doesn’t turn out to be successful. More importantly, we need better ways to better characterize donor diabetes in our donors.”

Additionally, if DMEK preparation is difficult in one eye, the surgeon should refrain from using the second eye of the pair and use the second graft for another purpose, Price said. – by Matt Hasson

Disclosure: Price reports financial relationships with Calhoun Vision, Interactive Medical Publishing, RevitalVision, STAAR Surgical, Strathspey Crown, TearLab and Transcend Medical.