Outcome of Descemet membrane endothelial keratoplasty for graft failure after Descemet stripping automated endothelial keratoplasty

Case Report: Role of Anterior Segment Optical Coherence Tomography for Managing Failed Endothelial Keratoplasty Graft

SIGNIFICANCE

Some patients show poor visual outcomes after Descemet stripping automated endothelial keratoplasty. In such cases, secondary Descemet membrane endothelial keratoplasty can be performed to achieve complete visual recovery. Anterior segment optical coherence tomography (AS-OCT) is a valuable tool for the follow-up of posterior lamellar keratoplasty outcomes and complications.

PURPOSE

This study aimed to report the clinical outcome of secondary Descemet membrane endothelial keratoplasty for managing poor visual results in a patient with graft failure after a previous Descemet stripping automated endothelial keratoplasty, highlighting the importance of AS-OCT in the follow-up of endothelial keratoplasty.

CASE REPORT

A 38-year-old woman with high myopia underwent Descemet stripping automated endothelial keratoplasty for bullous keratopathy after explantation of an angle-supported phakic intraocular lens. Two years after keratoplasty, the patient experienced poor visual acuity (counting fingers), and significant corneal edema was observed on clinical examination hindering visualization of the anterior chamber structures. Anterior segment optical coherence tomography showed a failed and thickened graft adhering well to the recipient cornea in an anterior chamber without other comorbidities. Therefore, the graft was removed and replaced with a Descemet membrane endothelial keratoplasty graft without any complications. One year later, the clinical outcome was evaluated by comparing the pre-operative and post-operative best-corrected visual acuity, biomicroscopy findings, endothelial cell density, and corneal central thickness.

CONCLUSIONS

Anterior segment optical coherence tomography is an important tool when deciding on the surgical technique to be applied and for the post-surgical monitoring of endothelial corneal grafts. This case demonstrates the successful management of Descemet stripping automated endothelial keratoplasty graft failure with Descemet membrane endothelial keratoplasty graft, highlighting the importance of AS-OCT in detecting complications such as graft dislocation and primary graft failure. In addition, corneal thickness measured using AS-OCT serves as a critical predictor of graft failure, as observed in this case.

A Comparison of the Corneal Thickness Following Descemet's Stripping Automated Endothelial Keratoplasty and Descemet's Membrane Endothelial Keratoplasty

PURPOSE

To compare the central corneal thickness before and after Descemet's stripping automated endothelial keratoplasty (DSAEK) and Descemet's membrane endothelial keratoplasty (DMEK), and to evaluate the recipient corneal thickness following DSAEK.

METHODS

The corneal thickness was compared between two groups of eyes following DMEK and DSAEK, performed by a single surgeon between 2015 and 2017. We evaluated the recipient corneal thickness and central corneal thickness pre- and postoperatively at 1, 3, and 6 months using anterior segment optical coherence tomography. Recipient corneal thickness was defined as the corneal thickness without graft thickness.

RESULTS

We included DMEK and DSAEK eyes (n = 26 each), which were similar in terms of their etiologies. Preoperatively, there was no significant difference in the central corneal thickness between the groups (DSAEK, median [interquartile range]: 721 [606.5 to 847.8] µm; and DMEK: 690 [618 to 722.3] µm; p = 0.30). Despite the tendency of the central corneal thickness to be significantly greater (p < .01) at 6 months following DSAEK (619.5 [607.8 to 661.3] µm) compared with that following DMEK (497.5 [475.8 to 525.3] µm), there was no significant difference at 6 months between the recipient corneal thickness following DSAEK (488.5 [443.8 to 515] µm) and central corneal thickness following DMEK (p = 0.54).

CONCLUSIONS

DSAEK eyes display a similar tendency of stromal thinning as DMEK eyes.

Etiology-Specific Comparison of the Long-Term Clinical Outcome of Repeat Deep Anterior Lamellar Keratoplasty for Optical Indications

PURPOSE

The aim of this study was to evaluate the etiology-specific clinical outcomes and complications of repeat deep anterior lamellar keratoplasty (DALK) after failed DALK.

METHODS

This retrospective case study included 32 eyes of 27 patients who underwent repeat DALK of 450 cases of DALK performed for optical indications between 1997 and 2013. The patients were divided into 4 etiology-specific subgroups (the corneal dystrophy, ocular surface disease, stromal scar, and others) or those with or without limbal stem cell deficiency (LSCD). The clinical outcomes evaluated were graft survival, best-corrected visual acuity, endothelial cell density, and complications.

RESULTS

The mean postoperative follow-up duration was 69.6 ± 54.8 months. The 1-, 3-, and 5-year overall graft survival rate were 76.7%, 57.5%, and 38.8% respectively. The graft survival rate was the highest in the corneal dystrophy group ( P = 0.0014) and was significantly ( P = 0.0010) higher in eyes without LSCD than in eyes with LSCD. There were no significant differences in the graft survival rates between the previous and current DALK groups. The postoperative best-corrected visual acuity of all subjects improved significantly. The postoperative endothelial cell density did not decrease after repeat DALK. There were no significant differences in the incidence of complications between patients with and without LSCD, except the incidence of persistent epithelial defects.

CONCLUSIONS

Repeat DALK had favorable outcomes in all etiology-specific groups, whereas eyes with LSCD required careful assessment of the ocular surface to avoid graft failure due to persistent epithelial defects.

Secondary Endothelial Keratoplasty-A Narrative Review of the Outcomes of Secondary Corneal Endothelial Allografts

BACKGROUND

We review the literature on the efficacy and safety outcomes of secondary Descemet stripping endothelial keratoplasty (DSEK) and Descemet membrane endothelial keratoplasty (DMEK).

METHODS

Literature search of English-written publications up to September 27, 2020 in PubMed database, using the terms "endothelial keratoplasty" in combination with keywords "secondary" or "repeat." In addition, we manually searched the references of the primary articles.

RESULTS

Twenty-seven studies (n = 651 eyes) were retained and reviewed, including 10 studies on repeat DSEK, 8 studies on repeat DMEK, 6 studies of DMEK following DSEK, and 3 studies of DSEK after failed DMEK. All studies reported significant improvement in visual acuity after secondary endothelial keratoplasty (EK). Twelve studies compared visual outcomes between primary and secondary EK, reporting conflicting findings. Sixteen studies reported endothelial cell loss rates after secondary EK, and only 1 study reported significantly increased endothelial cell loss rates compared with primary EK. Allograft rejection episodes occurred in 1.8% of eyes (range, 0%-50%). Six studies compared complication rates between primary and secondary EK eyes, and only 1 study found a higher median number of complications. However, 2 studies reported higher regraft failure rates compared with primary EK eyes.

CONCLUSIONS

Secondary EK is surgically feasible and renders significant visual improvement after failed primary EK, although it is not clear whether visual outcomes and allograft survival are comparable with primary EK, raising the question of whether secondary EK eyes are "low risk" as primary EK eyes. Further larger, prospective studies are encouraged to obtain additional quality data on secondary corneal endothelial allotransplantation.

Corneal transplantation after failed grafts: Options and outcomes

Corneal transplantation is the most commonly performed human tissue transplantation procedure worldwide. Because of the large number of transplants, corneal graft failure has become one of the most common indications for corneal transplantation. The relatively recently developed lamellar transplant techniques have brought about specific potential complications leading to graft failure that may require different approaches to repeat transplantation other than penetrating keratoplasty. On the other hand, these new lamellar techniques also provide novel ways of rescuing failed penetrating grafts, with potential advantages over successive penetrating keratoplasties, such as reduced intraoperative risks and faster visual rehabilitation. We summarize the incidence and risk factors of graft failure for penetrating and lamellar (stromal and endothelial) corneal transplants and discuss the various surgical alternatives currently available to rescue such failed grafts, with a focus on the reported outcomes and limitations.

Repeat Descemet Membrane Endothelial Keratoplasty for Failed Primary Descemet Membrane Endothelial Keratoplasty at a Referral Center for Keratoplasty in Spain: DIMOEK Study

PURPOSE

To analyze the clinical results of repeat Descemet membrane endothelial keratoplasty (re-DMEK) for failed primary DMEK graft at a referral center for keratoplasty in Spain.

DESIGN

Retrospective, interventional, comparative case series.

METHODS

From a single-center, single-surgeon series of 189 consecutive DMEK surgeries, 14 (7.41%) were re-DMEK eyes. The primary outcome was best-corrected visual acuity change (ΔBCVA, logarithm of minimal angle of resolution [logMAR]) from baseline (before first DMEK) to last follow-up. Secondary outcomes were ΔBCVA from baseline at 3, 6, and 12 months postoperatively, endothelial cell loss (%ECL), rebubbling rate, and re-DMEK graft failure. Outcomes were compared with an age-matched control group of 18 successful primary DMEK eyes.

RESULTS

After re-DMEK (median follow-up time 14.5 [42.5] months), mean BCVA improved from 0.55 (0.42) logMAR (Snellen 20/71 [20/53]) at baseline to 0.09 (0.26) logMAR (Snellen 20/25 [20/36]; P = .037). ΔBCVA from baseline was statistically significant at months 3 (P = .028), 6 (P = .023), and 12 (P = .012), and ΔBCVA was significant observed between months 6 and 12 (P = .028). BCVA differences between patient groups were statistically nonsignificant at 3 (P = .397), 6 (P = .468), and 12 months (P = .647). Mean %ECL in re-DMEK eyes with follow-up ≥12 months was 48.2 (15.1%), and the rebubbling rate was 28.6%; differences between groups were statistically nonsignificant for both variables (P = .580 and P = .669, respectively). Three re-DMEK eyes developed graft failure, all achieving final BCVA ≤0.30 logMAR (Snellen ≥20/40) after tertiary keratoplasty.

CONCLUSIONS

Repeat DMEK produces significant, continuous visual improvement after failed primary DMEK. Although visual outcomes and %ECL were comparable to primary DMEK, there was a relatively high rate of graft failure after re-DMEK.