DMEK for Fuchs’ Dystrophy

Early results lead to rapid uptake, cautious optimism on long-term outcomes. Cheryl Guttman Krader reports

Descemet membrane endothelial keratoplasty (DMEK) has changed the approach to managing corneal endothelial pathologies—particularly Fuchs’ endothelial corneal dystrophy (FECD), for which keratoplasty is being performed more often and earlier, according to Marc Muraine MD.

Reflecting on this shift, Dr Muraine noted a need for more information on long-term outcomes after DMEK.

“We all know that visual results after DMEK are impressive from the first postoperative week. Results at five years are excellent as well and help explain the increased number of transplanted patients. However, is it the best option to graft patients with FECD very early when they are just 50 to 55 years old?” he asked.

“The first results from a series with follow-up [up] to 10 years are becoming available, and they are good. But they show 20% of patients need a regraft, and many of the grafted patients were lost to follow-up. We need to know the long-term survival of a regraft. Let us not forget that a failed graft for Fuchs’ patients means they will have visual acuity much lower than the preoperative level. Therefore, management decisions need to be individualised.”

Early questions surrounding DMEK related to its technical difficulty. Therefore, for several years after DMEK’s introduction, several surgeons developed methodological variations aiming to increase surgical ease. In addition, developed techniques for eye banks to provide preloaded DMEK grafts take the risks of graft preparation out of surgeons’ hands and make the procedure faster and safer, Dr Muraine explained.

“Current debates about DMEK are no longer about the surgical technique itself. Different methods are used by surgeons and eye bank technicians and are more or less equivalent,” he noted.

DMEK FOR FECD The developments in DMEK surgical technique and the advent of preloaded DMEK grafts underlie rising numbers of DMEK procedures—a phenomenon demonstrated in various temporal analyses. For example, data from the French eye bank in Paris showed an exponential increase in the proportion of corneal grafts used for DMEK from 15% in 2015 to 60% in 2020.

Particularly interestingly are data on indications for keratoplasty procedures showing that as soon as surgeons perfected the DMEK technique in 2015, the number of surgeries for FECD exploded. Whereas there were only 60 procedures for FECD in 2010, the number rose to 150 in 2015 and reached 550 in 2020, Dr Muraine reported.

“It is as if we were facing an epidemic, but the incidence of FECD was not increasing. The main explanation is that patients could be transplanted more easily and therefore were undergoing surgery earlier in the evolution of the pathology. But if patients are undergoing transplantation with DMEK at an earlier age, it is absolutely necessary to know the long-term survival rate of DMEK in FECD so we can prepare them for the possibility of needing one or more transplants in the future.”

Discussing the literature on this topic, Dr Muraine said most published reports on postoperative results after DMEK are based on follow-up that does not exceed two years. Available studies published by Melles [et al] and Weller [et al] estimate that graft survival is between 90% and 95% at five years. The first studies with longer term follow-up are being published, but as Dr Muraine reviewed, the series suffer from high dropout rates.

The reports include a study by Weller and Kruse in which 66 patients were followed for at least eight years after DMEK. For this population that included 60 patients with FECD, the investigators reported an 80% graft survival rate at 10 years and mean endothelial density of 729 cells/mm3 .

“These good results should not make us forget that 20% of patients had to be regrafted and only 32% of the patients reached the 10-year visit as many were lost to follow-up,” Dr Muraine cautioned.

Melles and colleagues reported findings from a retrospective study that included 100 eyes operated on after the surgeons completed the DMEK learning curve. The results for 10-year graft survival and endothelial cell density in this study were similar to those reported by Weller and Kruse, but 52% of patients were lost to follow-up after six years.

In a retrospective study including 150 eyes that underwent DMEK for FECD or bullous keratopathy, Beşek [et al] reported that only 60% of grafts performed in eyes with FECD remained clear at seven years. Dr Muraine noted, however, that the cases in this study included those done during the surgeons’ learning curve.

Finally, in a series reported by Montesel [et al], the graft survival rate for endothelial keratoplasty cases was only 85% at five years, and it dropped steeply after seven or eight years.

“Thirty percent of the surgeries were for endothelial dystrophy, and only 40% of grafts were clear at 10 years,” Dr Muraine said.

“It is as if we were facing an epidemic, but the incidence of FECD was not increasing. The main explanation is that patients could be transplanted more easily and therefore were undergoing surgery earlier in the evolution of the pathology.”

This presentation was made at the ESCRS Virtual Winter Meeting 2022.

Marc Muraine MD is Professor and Head of the Ophthalmology Department, Charles Nicolle Hospital, Rouen, France. marc.muraine@chu-rouen.fr