One-Year Clinical Outcomes of Preloaded Descemet Membrane Endothelial Keratoplasty Versus Non-Preloaded Descemet Membrane Endothelial Keratoplasty

Validation of preloaded DMEK donor tissues: a laboratory-based study on endothelial cell viability and comparison of two F-mark inks

OBJECTIVE

To investigate endothelial cell loss (ECL) associated with Descemet membrane endothelial keratoplasty (DMEK) donor tissues preloaded in the DMEK RAPID transport system after 1 and 5 days and to compare prestamping with 2 different F-mark inks.

METHODS

DMEK donor tissues were stripped, marked with gentian violet dye applied as an F-mark, trephined, stained with trypan blue, and then preloaded into the DMEK RAPID transport system by an eye bank technician. Preloaded DMEK tissues were then unfolded and stained with calcein AM after 1 or 5 days of storage. Tissues were imaged, analyzed for total tissue ECL, and immunostained for corneal endothelium markers zonular occludens-1 and xCD166. Additionally, ECL and the intensity of an F-mark caused by 2 different inks were quantified.

RESULTS

Preloaded DMEK tissues displayed an average ECL of 11.9% ± 4.5% (n = 8) at 1 day and 9.9% ± 4.2% (n = 9) at 5 days. No difference was found between the 2 groups. Zonular occludens-1 and activated leukocyte cell adhesion molecule (ALCAM; also know as CD166) staining showed that the corneal endothelial monolayer remained intact on preloaded tissues. On 5-day preloaded DMEK tissues, the average ECL and mean grayscale caused by the Keir Surgical ink F-mark and the Cardinal Health ink F-mark were 4.3% ± 0.8% and 158.5 ± 13.9% and 5.0% ± 1.1% and 142.9% ± 20.0%, respectively. No difference was found between the F-mark inks.

CONCLUSION

Preloaded DMEK donor tissues resulted in an acceptable ECL range after 1 and 5 days of storage and were deemed suitable for transplantation. Both F-mark inks are acceptable for prestamping preloaded DMEK tissues prior to surgical transplantation with comparable ECL and intensities.

Preloaded DMEK With Endothelium Outward: A Multicenter Clinical Study Using DMEK Rapid Device

PURPOSE

The objective of this study is to validate Descemet membrane endothelial keratoplasty (DMEK) Rapid device for preloading DMEK grafts with endothelium outward.

METHODS

In this multicenter retrospective clinical study, DMEK tissues (n = 27) were peeled and preloaded (8.25 mm) in a DMEK Rapid device. The device was loaded in a container prefilled with the storage solution and shipped from a single center in Italy to 4 different centers located in Italy and the United Kingdom. Preloaded tissues were delivered by injecting the graft in the anterior chamber. Patients were monitored at days 1 and 15 and at months 1, 3, and 6, as well as at the last follow-up (9-12 months) postoperatively. Main outcome measures included rebubbling rate and graft failure, corrected distance visual acuity, endothelial cell loss (ECL), and central corneal thickness at all time points. A one-way analysis of variance test comparing day 1 with all later time points was followed with significance at P < 0.05.

RESULTS

The average recorded surgical time was 6 to 25 minutes with no immediate surgical complications. Rebubbling was observed in 7 of 26 cases with one graft failure within 15 days postoperatively. The mean corrected distance visual acuity at day 1 was 0.64 ± 0.49 logMAR, which improved to 0.18 ± 0.43 logMAR at the last follow-up. Endothelial cell density values showed a significant decrease at the last follow-up (1827 ± 565 cells/mm 2 ) ( P < 0.001) compared with the preoperative value (2503 ± 128 cells/mm 2 ), with an average endothelial cell loss of 27%. Central corneal thickness significantly dropped from 694 ± 157 μm at day 1 to 502 ± 42 μm at the last follow-up ( P < 0.001).

CONCLUSIONS

DMEK Rapid device is quick, easy, and efficient for preloading and shipping DMEK grafts internationally in endothelium-outward orientation.

Non-invasive endothelial cell density measurement of in toto pre-stripped DMEK-roll - impact of pre- and intraoperative endothelial cell loss on postoperative midterm clinical outcome

BACKGROUND/OBJECTIVES

To measure the endothelial cell density (ECD) of the in toto pre-stripped endothelial Descemet membrane lamellae (EDML) and to describe the impact of pre- and intraoperative endothelial cell loss (ECL) on postoperative midterm clinical outcome.

SUBJECTS/METHODS

The ECD of 56 Corneoscleral Donor Discs (CDD) was first measured with an inverted specular microscope (t0pre). The measurement was then repeated non-invasively after the preparation of the EDML (t0post). DMEK was performed the next day using these grafts. Follow-up examinations took place 6 weeks, 6 months and 1 year postoperatively where the ECD was assessed. In addition, the impact of ECL 1 (during preparation) and ECL 2 (during surgery) on the ECD, visual acuity (VA) and pachymetry at 6 months and 1 year was investigated.

RESULTS

The average ECD (in cells/mm²) at time points t0pre, t0post, 6 weeks, 6 months & 1 year was 2584 ± 200, 2355 ± 207, 1366 ± 345, 1091 ± 564 and 939 ± 352. The average logMAR VA and pachymetry (in µm) was 0.50 ± 0.27 and 597 ± 63, 0.23 ± 0.17 and 535 ± 54, 0.16 ± 0.12 and 535 ± 54, 0.06 ± 0.08 and 512 ± 37, respectively The ECL 1 (9% on average) had no significant impact on the main outcome measures after 6 months and 1 year (p > 0.11). The ECL 2 correlated significantly with the ECD and the pachymetry at 1 year postop (p < 0.02).

CONCLUSION

Our results indicate that the non-invasive ECD measurement of the prestripped EDML roll before its transplantation is feasible. Despite significantly decreasing ECD up to 6 months postoperatively, visual acuity further improved and thickness further decreased up to 1 year postoperatively.

Cost Drivers of Endothelial Keratoplasty: A Time-Driven Activity-Based Costing Analysis

PURPOSE

To determine cost drivers of endothelial keratoplasty (EK) through evaluation of surgical costs and procedure length based on type of EK, use of preloaded grafts, and performance of simultaneous cataract surgery.

DESIGN

This study was an economic analysis of EKs at a single academic institution using time-driven activity-based costing (TDABC) methodology.

PARTICIPANTS

Endothelial keratoplasty surgical cases, including Descemet membrane endothelial keratoplasty (DMEK) and Descemet stripping automated endothelial keratoplasty (DSAEK), at the University of Michigan Kellogg Eye Center from 2016 to 2018 were included in the analysis.

METHODS

Data and inputs were obtained via the electronic health record (EHR) and from prior literature. Simultaneous cataract surgeries were included and separately categorized for analysis. Endothelial keratoplasty expenses were determined with TDABC, a method for cost calculation that incorporates the time that key resources are used and each resource's associated cost rate.

MAIN OUTCOME MEASURES

Main outcome measures included surgery length (in minutes) and day-of-surgery costs.

RESULTS

There were 559 EKs included: 355 DMEKs and 204 DSAEKs. Fewer DSAEKs had simultaneous cataract extraction (47; 23%) than DMEK (169; 48%). Of the DMEKs, 196 (55%) used preloaded corneal grafts. Descemet membrane endothelial keratoplasty cost $392.31 less (95% confidence interval, $251.05-$533.57; P < 0.0001) than DSAEK and required 16.94 fewer minutes (14.16-19.73; P < 0.0001). Descemet membrane endothelial keratoplasty cases that used preloaded corneal grafts cost $460.19 less ($316.23-$604.14; P < 0.0001) and were 14.16 minutes shorter (11.39-16.93; P < 0.0001). In multivariate regression, preloaded graft use saved $457.19, DMEK (compared with DSAEK) saved $349.97, and simultaneous cataract surgery added $855.17 in day-of-surgery costs.

CONCLUSIONS

Cost analysis of TDABC identified a day-of-surgery cost and surgical time reduction associated with the use of preloaded grafts for DMEK, DMEK compared with DSAEK, and isolated EK compared with EK combined with cataract surgery. This study provides an improved understanding of surgical cost drivers and margin incentivization, which may explain trends and indirectly influence patient care decisions in cornea surgery practices.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Trends in Keratoplasty Procedures During 2 Decades in a Major Tertiary Referral Center in Finland: 1995 to 2015

PURPOSE

The purpose of this study was to analyze trends in number, age-adjusted frequency, and type of keratoplasty in a major tertiary referral center, relative to patient and graft characteristics.

METHODS

A retrospective registry study of 1574 patients who in 1995 to 2015 underwent keratoplasty in the Helsinki University Eye Hospital (HUEH). Graft type and sequence, patient characteristics, and date of surgery were recorded. Main outcome measures were annual number, type, and age-adjusted frequency of keratoplasty; patient and graft characteristics; graft procurement; and national population-adjusted frequency of keratoplasty.

RESULTS

In HUEH, from 1995 to 2015, a total of 2191 keratoplasties were performed with 48% of the grafts procured intramurally; 76% were primary and 24% regrafts. The age-adjusted frequency of primary penetrating keratoplasty decreased by 52% from 0.96 to 0.46 per 100,000. The corresponding frequency of primary Descemet stripping automated endothelial keratoplasty increased by 367% from 0.3 to 1.4 after 2006, finally accounting for 68% of primary grafts. Men underwent primary penetrating keratoplasty (median 48 vs. 67 yrs, P = 0.0001) and anterior lamellar keratoplasty (median 37 vs. 46 yrs, P = 0.0015) at a younger age than women. Interval to the first regraft was comparable between sexes (median 2.2 vs. 1.9 yrs, respectively, P = 0.17). The national median population-adjusted frequency of keratoplasties was 3.2 per 100,000 from 2009 to 2015, and HUEH accounted for a median of 69% of them.

CONCLUSIONS

The increased frequency of keratoplasty in HUEH resulted from rapid adoption of Descemet stripping automated endothelial keratoplasty after 2006 and was facilitated by centralizing graft procurement to HUEH and the National Cell and Tissue Center Regea.

Indications and techniques of corneal transplants performed in one center in Southern Poland, in the years 2001–2020

Purpose

The study aimed to evaluate changes over a period of time in techniques and indications for corneal transplantation in a single center in Poland.

Methods

Retrospective analysis of corneal transplants performed at the Ophthalmology Department of the District Railway Hospital in Katowice in 2001–2020. Data on indications and surgical technique were collected.

Results

A total of 3021 corneal transplantations were performed in the years 2000–2020. The most common technique was penetrating keratoplasty (69,54%), then lamellar grafts—both anterior and posterior (19,63%), and limbal grafts (10,82%). Only in 2007 the number of lamellar keratoplasties exceeded the number of penetrating grafts and accounted for 108 (54,55%), including 85 (42,93%) of Descemet Stripping Automated Endothelial Keratoplasty. The only noticeable trend in changing techniques was a decrease in the number of performed deep anterior lamellar keratoplasties (r 2 = -0.21) over the last seven years. Main indications included bullous keratopathy (23,22%), following keratoconus (18,59%), leukoma (14,67%), keratitis and perforation (14,3%), Fuchs dystrophy (11,4%), and regrafts (7,22%). Leukoma and bullous keratopathy as an indications for corneal transplant have been declining over the years (r2 = 0.60 and r2 = 0.30 respectively). Consecutively, indications such as fuchs dystrophy, regraft and keratitis perforation have increased (r2 = 0.05, r2 = 0.50, r2 = 0.33)

Conclusions

The number of keratoplasties gradually increased from 2001 to 2020. It could be possible that the development and spread of new therapeutic alternatives, like corneal cross-linking and scleral lenses, have contributed to the decrease in deep anterior lamellar keratoplasty performed. There was an increasing trend in the percentage of penetrating keratoplasties for failed grafts, Fuchs dystrophy and infectious keratitis.

“Endothelium-Out” and “Endothelium-In” Descemet Membrane Endothelial Keratoplasty (DMEK) Graft Insertion Techniques: A Systematic Review With Meta-Analysis

Background

We evaluated the visual outcomes and complications of “endothelium-out” and “endothelium-in” Descemet membrane endothelial keratoplasty (DMEK) graft insertion techniques.

Materials and Methods

Electronic searches were conducted in CENTRAL, Cochrane databases, PubMed, EMBASE, ClinicalTrials.gov. Study designs included clinical trials, comparative observational studies, and large case series (≥25 eyes). PRISMA guidelines were used for abstracting data and synthesis. Random-effects models were employed for meta-analyses.

Results

21,323 eyes (95 studies) were included. Eighty-six studies reported on “endothelium-out” techniques; eight studies reported on “endothelium-in” techniques. One study compared “endothelium-out” to “endothelium-in” techniques. Eighteen “endothelium-out” studies reported that 42.5–85% of eyes achieved best-corrected visual acuity (BCVA) ≥20/25 at 6 months; pooled proportion of eyes achieving BCVA ≥20/25 at 6 months was 58.7% (95% CI 49.4–67.7%,15 studies). Three “endothelium-in” studies reported that 44.7–87.5% of eyes achieved BCVA of ≥20/25 at 6 months; pooled proportion of eyes achieving BCVA ≥20/25 at 6 months was 62.4% (95% CI 33.9–86.9%). Pooled mean endothelial cell loss was lower in the “endothelium-in” studies (28.1 ± 1.3%, 7 studies) compared to “endothelium-out” studies (36.3 ± 6.9%,10 studies) at 6 months (p = 0.018). Graft re-bubbling rates were higher in the “endothelium-out” studies (26.2%, 95% CI 21.9–30.9%, 74 studies) compared to “endothelium-in” studies (16.5%, 95% CI 8.5–26.4%, 6 studies), although statistical significance was not reached (p = 0.440). Primary graft failure rates were comparable between the two groups (p = 0.552). Quality of evidence was considered low and significant heterogeneity existed amongst the studies.

Conclusion

Reported rates of endothelial cell loss were lower in “endothelium-in” DMEK studies at 6 months compared to “endothelium-out” studies. Outcomes of “endothelium-in” techniques were otherwise comparable to those reported in “endothelium-out” studies. Given the technical challenges encountered in “endothelium-out” procedures, surgeons may consider “endothelium-in” techniques designed for easier intra-operative DMEK graft unfolding. “Endothelium-in” studies evaluating outcomes at longer time points are required before conclusive comparisons between the two techniques can be drawn.

Graft detachments in endothelial keratoplasty

Graft detachment is the most common complication of endothelial keratoplasty. With the ongoing advancements in the field of endothelial keratoplasty, our understanding of risk factors of graft detachments and its management has been evolving. Various prevention measures have been described in literature including presoaking the donor graft, anterior chamber tamponade, venting incisions, sutures to prevent dislocation of graft. Management of a detached graft involves secondary interventions such as rebubbling, suturing and regrafts. In this review, we discuss graft detachment in different types of endothelial keratoplasty techniques including Descemet stripping endothelial keratoplasty, Descemet stripping automated endothelial keratoplasty and Descemet's membrane endothelial keratoplasty; with emphasis on incidence, risk factors, preventive measures and their management.