A Clinicopathologic Series of Primary GraftFailure after Descemet’s Stripping andAutomated Endothelial Keratoplasty

Stephen F. Oster, MD, PhD, Katayoon B. Ebrahimi, MD, Charles G. Eberhart, MD, PhD,Oliver D. Schein, MD, MPH, Walter J. Stark, MD, Albert S. Jun, MD, PhD

Purpose: To characterize the clinical and histologic features of primary graft failure after Descemet’sstripping and automated endothelial keratoplasty (DSAEK).

Design: Retrospective observational case series.Participants: Sixteen cases of DSAEK graft failure from 15 patients, all with detailed histologic examination

of failed graft tissue.Methods: Hematoxylin-eosin, periodic acid-Schiff staining, and light microscopy were used to examine the

failed DSAEK graft tissue from all patients.Main Outcome Measures: Examination of specimens for corneal endothelial cell viability and host–donor

interface characteristics.Results: Clinical history revealed that 88% (14/16) of studied DSAEK grafts detached before failure, and

pathologic examination found that 75% (12/16) of failed grafts had atrophic corneal endothelium. Examples ofresidual host Descemet’s membrane in the graft site and improper donor trephination were also identified.

Conclusions: Marked loss of the corneal endothelium is the prominent feature of primary DSAEK graftfailure. Examples of surgical features, such as incomplete Descemet’s stripping and residual full-thicknesscornea with a DSAEK graft, are shown.

Financial Disclosure(s): Proprietary or commercial disclosure may be found after the references.

Ophthalmology 2009;116:609–614 © 2009 by the American Academy of Ophthalmology.

Endothelial keratoplasty (EK) is a surgical treatment for cor-neal endothelial dysfunction. Growing in popularity, EK en-tails transplantation of only the corneal endothelium and pos-terior corneal lamellae for cases of endothelial decompensation.EK techniques have evolved rapidly over the last several years,and currently the most common approach is Descemet’s strip-ping and endothelial keratoplasty (DSEK).1 When the donortissue is prepared using an automated microkeratome, theprocedure is generally referred to as Descemet’s stripping andautomated endothelial keratoplasty (DSAEK).

Advantages of DSAEK over traditional penetrating ker-atoplasty (PK) include more rapid recovery times andgreatly reduced postoperative astigmatism and refractivechanges.2 However, DSAEK surgery has a unique set ofdifficulties, including graft detachment. Detachments areusually treated with graft repositioning assisted by an ante-rior chamber air bubble. DSAEK grafts that will not reattachor never clear postoperatively are referred to as cases ofprimary graft failure (PGF). Several surgical techniqueshave been developed to reduce graft detachment, and theseinclude microincision fluid drainage from the graft–hostinterface3 and roughening of the recipient stromal bed.4 Asexpected, these modifications in technique improvedDSAEK failure rates.3 Reported DSAEK PGF rates rangefrom 1% in experienced hands up to 12%.3,5,6

To date, limited pathologic information is available

about the underlying causes of graft detachment and failure.

© 2009 by the American Academy of OphthalmologyPublished by Elsevier Inc.

One possibility is that donor endothelial cell loss leaves thedonor tissue unable to properly adhere to host stroma or tophysiologically clear the host cornea. A second hypothesisis that poor adhesion at the graft–host interface leads todislocation and ultimately, failure. This is supported byelectron microscopic studies revealing that the host DSAEKstromal bed is remarkably smooth after Descemet’s strip-ping, and that roughening the stromal bed improves adher-ence and DSAEK success.3

Currently, histology is available from only 1 pair of PGFcase reports, both of which suggest that incompletelystripped host Descemet’s membrane interfered with thehost–graft interface.7,8 In one instance, residual fetal De-scemet’s membrane remained in the graft site after strip-ping, leading to nonadherence and ultimate progression toPK despite healthy donor corneal endothelium.7 However,in the second report, failed graft tissue was not available forexamination, and the state of the donor corneal endotheliumcould not be evaluated.7 We report a clinicopathologicseries of 16 failed DSAEK graft tissues submitted to asingle eye pathology laboratory.

Materials and Methods

Johns Hopkins Institutional Review Board approval was grantedfor this study, and patients were identified by searching the Wilmer

Eye Institute pathology laboratory database. Sixteen samples of

609ISSN 0161-6420/09/$–see front matterdoi:10.1016/j.ophtha.2008.08.036

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DSAEK tissue excised from 15 different patients in the setting ofrepeat surgery, either another DSAEK or PK, were obtained forreview. Corresponding patient clinical data were collected retro-spectively. These data included details of the donor tissue andclinical presentation and postoperative course of each patient fromthe date of initial DSAEK surgery. All surgical procedures, in-cluding initial DSAEKs and follow-up DSAEKs or PKs, wereperformed by 4 surgeons (ASJ, ODS, WJS, and John D. Gottsch,MD), and the DSAEK surgical technique was as previously de-scribed.9 All donor tissues were obtained from an eyebank andpresectioned using an automated microkeratome. Operative noteswere reviewed for all cases to identify any specific intraoperativeevents that might contribute to subsequent graft dislocation orfailure.

Each surgical specimen was processed in a routine fashion forpathologic review, including 10% buffered formalin fixation followedby paraffin embedding and sectioning. For each specimen, sectionswere stained with hematoxylin-eosin and periodic acid-Schiff. Lightmicroscopy images were acquired with a Diagnostic Instruments(Sterling Heights, MI) digital camera mounted on an Olympus BX50light microscope (Olympus Optical Co, Tokyo, Japan).

Results

Sixteen failed DSAEK grafts from 15 different patients are in-cluded in this study. Patients were evenly divided between maleand female, and ages ranged from 61 to 87 years (Table 1).Seventy-five percent of patients (12/16) had a repeat DSAEK, and25% of patients (4/16) were treated with a PK after failed DSAEK.The average time to the second surgery was 4 months (Table 1).The majority of patients had Fuchs’ dystrophy, and 44% (7/16)underwent simultaneous cataract surgery (Table 1). Preoperativevisual acuity and pachymetry measurements are available in Table1. Table 2 outlines the donor tissue characteristics. No graft was instorage more than 7 days, and the average endothelial cell countwas 3024. Donor age ranged from 25 to 68 years, and averagepreoperative graft thickness ranged from 107 to 207 �m with anaverage of 156 �m.

Table 1. Patie

PatientNo.

Age andGender

UnderlyingDisease Ocular Comorbidities

1 80, M Fuchs’ dystrophy POAG2 86, F Fuchs’ dystrophy PPV3 87, F PBK Uveitic glaucoma, TS4 69, F PBK POAG, trabeculectomy, PPV5 76, M Fuchs’ dystrophy6 76, M Fuchs’ dystrophy Cataract7 77, F Fuchs’ dystrophy8 61, F Fuchs’ dystrophy LASIK9 67, F Fuchs’ dystrophy Cataract

10 63, F Fuchs’ dystrophy Cataract11 64, M Fuchs’ dystrophy Cataract12 79, M Fuchs’ dystrophy Cataract13 76, F Fuchs’ dystrophy Cataract14* 73, M Fuchs’ dystrophy Cataract14* 73, M Failed DSAEK15 72, M PBK

CF � count fingers; DSAEK � Descemet’s stripping and automated endotPK � penetrating keratoplasty; POAG � primary open angle glaucoma;

*Patient 14 underwent DSAEK twice and then a PK.

610

Eighty-eight percent (14/16) of the failed grafts separated fromthe stromal bed postoperatively after DSAEK, and 9 of these(64%) were repositioned at least once (Table 3). Two of theDSAEK grafts remained attached, but the host corneas did notclear. Five grafts were completely detached and either free-floatingin the anterior chamber or had settled into an off-center position,and 9 grafts were detached with a partial separation or fluid pocketbetween graft and host (Table 3).

On histologic examination, 75% of specimens (12/16) exhibitedatrophic corneal endothelium with 1 or no endothelial cell per 400-fold microscopic field (Fig 1A, B). This included 1 clinically well-positioned DSAEK graft without viable endothelium, and the demar-cation can be seen histologically between host and graft tissue evenwhen properly apposed (Fig 1C). Among the remaining 4 grafts withviable endothelial cells, 2 had a notable reduction in the normalcorneal endothelial cell density (patients 10 and 12) and 2 had func-tional appearing endothelial cell layers (patients 3 and 11, Fig 1D).

Examination also disclosed additional mechanical complicationsof DSAEK surgery. Residual host Descemet’s membrane was seen inthe graft–host interface twice in our series (Fig 2A, B), suggesting thatincomplete stripping of Descemet’s membrane occurred before graftplacement. Both of these grafts detached before graft failure (patients4 and 7, Table 3). In addition, in 1 patient the donor tissue wasimproperly cut, leaving a portion of full-thickness cornea in theperipheral graft (Fig 2C, D) that did not attach properly before failure(patient 6, Table 3). Finally, the stromal portion of 2 grafts appearedmarkedly acellular (patients 5 and 14, Table 3), with a loss ofkeratocytes and no evidence of inflammation. In 1 of these grafts therewere no viable endothelial cells (Fig 1B), and in the other graft only1 endothelial cell per high-magnification field remained.

Discussion

We report a histopathologic analysis of DSAEK graft tissueafter PGF. The most common feature of PGF was theoccurrence of graft detachment in 88% of cases. This asso-ciation is consistent with previous reports on DSAEK out-comes in which cases of graft failure generally followed

haracteristics

reoperativeVisualAcuity

PreoperativePachymetry

(�m)F/U Surgery,

Interval Notes

20/60 629 DSAEK, 8 mo20/200 721 DSAEK, 2 mo20/200 804 PK, 10 mo TS revision2/200 Unknown PK, 3,5 mo Synechialysis

20/50 700 DSAEK, 9 mo20/80 790 DSAEK, 3 wks Phacoemulsification20/70 675 DSAEK, 1 mo20/60 650 DSAEK, 1 mo20/40 658 DSAEK, 4 mo Phacoemulsification20/400 720 DSAEK, 1 mo Phacoemulsification20/60 623 DSAEK, 1 mo Phacoemulsification20/100 575 DSAEK, 3 mo Phacoemulsification20/50 659 DSAEK, 8 mo Phacoemulsification20/60 659 DSAEK, 4 mo Phacoemulsification2/200 Re-DSAEK PK, 2 wkCF 850 PK, 8 mo

keratoplasty; F/U � follow-up; PBK � pseudophakic bullous keratopathy;� pars plana vitrectomy; TS � tube shunt.

nt C

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Oster et al � Clinicopathologic Series of Primary Graft Failure in DSAEK

detachment and failure rates improved as detachments de-creased.3,4 An atrophic corneal endothelium was found in75% of failed grafts. The loss of endothelial cells likelycontributes to graft detachment, and it essentially ensuresPGF because the cornea will not clear. Previous studieshave documented a reduction in corneal endothelial celldensity over time in successful DSAEK surgery.10 Moststriking among these was a report of 50% loss within thefirst 6 months after surgery comparing preoperative endo-thelial counts with postoperative specular microscopy.11

The precise timing of endothelial cell loss is unclear,although graft manipulation during insertion and position-ing seems most likely given the growing body of evidenceshowing that donor tissue handling and forceps manipula-tion lead to endothelial cell death.12,13 Toxicity from additionalmanipulations and exposure to air during repositioning also

Table 2. Gra

Patient No. Donor Age (y) Time to Preservation (h:min

1 64 10:152 46 16:223 25 8:544 68 15:015 59 17:406 29 10:407 33 19:208 N/A N/A9 24 13:38

10 58 6:3811 44 8:4512 61 17:5313 N/A N/A14 62 8:2714 55 5:3315 55 15:58

DSAEK � Descemet’s stripping and automated endothelial keratoplasty;by contacting the eyebank).

Table 3. Fail

Patient No. Endothelial Cell Count Postoperative Graft Positio

1 0 Completely detached2 1 Partially detached3 10 Well positioned4 0 Partially detached5 0 Partially detached6 0 Partially detached7 0 Partially detached8 0 Partially detached9 1 Partially detached

10 6 Completely detached11 14 Completely detached12 7 Completely detached13 1 Completely detached14 1 Partially detached14 1 Partially detached15 0 Well positioned

SF6 � sulfur hexafluoride gas.

may contribute to cell loss.14,15 Evidence of cell-mediatedimmunologic rejection, or of any acute inflammatory reaction,in the donor graft or graft–host interface was not detected inour patients, consistent with published reports that immune-mediated graft rejection is uncommon after EK.16 Finally, arecent retrospective series labeled DSAEK combined withphacoemulsification “the new triple procedure,”17 and 7 of the16 failed DSAEKs reported here were combined with cataractsurgery. On comparison, we found no histologic differencesamong failed grafts performed with or without concurrentphacoemulsification.

It is self-evident that careful surgical management of theDSAEK graft–host interface is crucial for success. Detach-ment rates and failure rates clearly improve with techniquesto optimize interface adhesion, such as roughening the hoststromal bed or draining residual fluid from the graft inter-

aracteristics

Preservation toDSAEK (d)

Endothelial CellCount

Preoperative GraftThickness (�m)

N/A 3484 1534 3125 1703 2994 N/A7 2976 1386 2824 1976 N/A N/A3 3322 167

N/A 3205 127N/A 3344 140

5 3125 1076 2808 2076 2923 150

N/A 2500 N/A6 3086 N/A6 2645 N/A

N/A 2994 N/A

not available (information could not be found in the clinical record or

raft Features

Graft Manipulations Notes

Reposition � 1Reposition � 1None Corneal ulcerReposition � 3 (Air � 2, SF6 � 1) Residual host Descemet’sReposition � 2 No keratocytes in graftNone Full thickness cornea in graftNone Residual host Descemet’sNoneReposition � 1NoneReposition � 1Reposition � 2Reposition � 1Reposition � 1 No keratocytes in graftNoneNone

ft Ch

)

N/A �

ed G

n

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face.3,4 Two recent case reports highlighted incompletelystripped host Descemet’s membrane in the stromal bed of afailed DSAEK graft,7,8 and the same feature is seen in 2specimens included in this series (Fig 2A, B). Both times,Descemet’s membrane is separated from the host stroma,suggesting that stripping occurred, but the stripped tissuewas not completely removed from the anterior chamberbefore grafting. Both of the grafts in this series detachedbefore failure, and the residual Descemet’s membrane in theinterface likely contributed to poor donor adhesion.

Also illustrated in our series is donor tissue detach-ment resulting from a portion of full-thickness cornea at1 edge of the DSAEK graft. Histologic examination ofthis specimen reveals donor Bowman’s membrane, full-thickness corneal stroma, and donor Descemet’s mem-brane at 1 edge of the graft (Fig 2C, D), all of whichlikely occurred because of the off-centered trephination

Figure 1. Failed Descemet’s stripping and automated endothelial keratoplasfailed DSAEK graft with keratocyte nuclei seen in the stroma and no coPAS-stained failed DSAEK graft without viable keratocytes or endothelial ceafter a PK) with no remaining corneal endothelial cells. This specimen highlwithout viable endothelial cells. D, 200-fold magnification hematoxylin-eocorneal endothelial cells.

of donor corneal tissue.

612

Two of the failed DSAEK grafts included in our studyhad acellular corneal stroma with a complete loss of ker-atocytes along with absolute endothelial loss in 1 specimenand near-total loss in the other. This previously unreportedobservation related to DSAEK surgery carries unclear sig-nificance. Literature related to refractive surgery has showna recoverable loss of keratocytes after corneal flap creation,corneal scraping, or epithelial loss,18 and the process ofsectioning thin posterior corneal lamellae may have a sim-ilar effect. Alternately, total loss of donor cellularity couldindicate nonviable corneal stroma and endothelium result-ing from extreme intraoperative or postoperative events.The anterior portions of the donor corneas from which the 2acellular DSAEK grafts were taken both appeared normalon histologic examination. This suggests that storage con-ditions, eye bank processing, and preoperative tissue carewere adequate in both instances, and that surgical or post-

AEK) grafts. A, 200-fold magnification periodic acid-Schiff (PAS)–stainedendothelial cells along Descemet’s membrane. B, 200-fold magnification200-fold magnification PAS-stained attached and failed DSAEK graft (now

the graft–host stromal interface (arrows) and the possibility of graft adhesionained detached and failed DSAEK graft with intact and normal-appearing

ty (DSrneallls. C,ightssin–st

operative factors caused keratocyte loss.

ith n

Oster et al � Clinicopathologic Series of Primary Graft Failure in DSAEK

Our findings confirm the strong relationship betweendonor tissue detachment and graft failure and illustrate theassociation of PGF with profound endothelial cell loss.

References

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2. Price FW Jr, Price MO. Descemet’s stripping with endothelialkeratoplasty in 50 eyes: a refractive neutral corneal transplant.J Refract Surg 2005;21:339–45.

3. Price FW Jr, Price MO. Descemet’s stripping with endothelialkeratoplasty in 200 eyes: early challenges and techniques toenhance donor adherence. J Cataract Refract Surg 2006;32:

Figure 2. Mechanical graft complications. A, 100-fold magnification PA(DSAEK) graft sandwiched by residual host Descemet’s membrane (arrowperiodic acid-Schiff (PAS) stained failed DSAEK graft with residual hostmembrane on the graft (arrowhead). C, 40-fold magnification PAS-staiDescemet’s membrane (arrow). D, 100-fold magnification of the full-tendothelium is seen on 1 face (arrow), and intact Bowman’s membrane w

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4. Terry MA, Hoar KL, Wall J, Ousley P. Histology of disloca-tions in endothelial keratoplasty (DSEK and DLEK): a labo-ratory-based, surgical solution to dislocation in 100 consecu-tive DSEK cases. Cornea 2006;25:926–32.

5. Gorovoy MS. Descemet-stripping automated endothelial ker-atoplasty. Cornea 2006;25:886–9.

6. Koenig SB, Covert DJ. Early results of small-incision De-scemet’s stripping and automated endothelial keratoplasty.Ophthalmology 2007;114:221–6.

7. Mondloch MC, Giegengack M, Terry MA, Wilson DJ.Histological evidence of retained fetal layer of the De-scemet membrane after presumed total removal for endo-thelial keratoplasty: a possible cause for graft failure. Cor-nea 2007;26:1263– 6.

8. Kymionis GD, Suh LH, Dubovy SR, Yoo SH. Diagnosis ofresidual Descemet’s membrane after Descemet’s strippingendothelial keratoplasty with anterior segment optical coher-

ined failed Descemet’s stripping and automated endothelial keratoplastydonor Descemet’s membrane (arrowhead). B, 200-fold magnification of amet’s membrane (arrow) in the donor stromal bed and donor Descemet’siled DSAEK graft with full-thickness donor corneal lamella at 1 end.

ess portion of the graft in C. Descemet’s membrane with no cornealo corneal epithelium is seen on the opposite face (arrowhead).

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9. Wang Z, Handa JT, Green WR, et al. Advanced glycation endproducts and receptors in Fuchs’ dystrophy corneas undergo-ing Descemet’s stripping with endothelial keratoplasty. Oph-thalmology 2007;114:1453–60.

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12. Kuo AN, Harvey TM, Afshari NA. Novel delivery methodto reduce endothelial injury in Descemet stripping auto-mated endothelial keratoplasty. Am J Ophthalmol 2008;145:91– 6.

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The authors have no conflicts of interest related to the article.

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DSAEK donor tissue viability by using an in vitro deliverymodel and vital dye assay. Cornea 2007;26:1079–81.

14. Olson RJ. Air and the corneal endothelium: an in vivospecular microscopy study in cats. Arch Ophthalmol 1980;98:1283– 4.

15. Eiferman RA, Wilkins EL. The effect of air on human cornealendothelium. Am J Ophthalmol 1981;92:328–31.

16. Allan BD, Terry MA, Price FW Jr, et al. Corneal transplantrejection rate and severity after endothelial keratoplasty. Cor-nea 2007;26:1039–42.

17. Covert DJ, Koenig SB. New triple procedure: Descemet’sstripping and automated endothelial keratoplasty combinedwith phacoemulsification and intraocular lens implantation.Ophthalmology 2007;114:1272–7.

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Footnotes and Financial Disclosures

Originally received: January 27, 2008.Final revision: August 13, 2008.Accepted: August 14, 2008.Available online: October 29, 2009. Manuscript no. 2008-130.

Wilmer Eye Institute, The Johns Hopkins Hospital, Baltimore, Maryland.

Financial Disclosure(s):

Supported by a Research to Prevent Blindness Career Development Award(ASJ) and the Whitener and Roten funds (CGE).

Correspondence:

Albert S. Jun, MD, PhD, Wilmer Eye Institute, Woods 474, 600 N. Wolfe

St., Baltimore, MD 21287. E-mail: aljun@jhmi.edu.