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Descemet Stripping Automated Endothelial Keratoplasty in Failed Penetrating Keratoplasty Patients
In conclusion, although the authors have described valuable data on an Asian population, nonavailability of important data like duration of follow-up, raw data in various subgroups, and more survival analysis data involving risk factors other than glaucoma and allograft rejection leaves many questions unanswered. DEBARATHI SAHA MERLE FERNANDES SUSHMITA G. SHAH I. S. MURTHY
Visakhapatnam, Andhra Pradesh, India
REFERENCES
1. Anshu A, Lim LS, Htoon HM, Tan DT. Postoperative risk factors influencing corneal graft survival in the Singapore Corneal Transplant Study. Am J Ophthalmol 2011;151(3): 442– 448. 2. Sharma N, Sachdev R, Jhanji V, et al. Therapeutic keratoplasty for microbial keratitis. Curr Opin Ophthalmol 2010; 21(4):293–300. 3. Tan DT, Janardhanan P, Zhou H, et al. Penetrating keratoplasty in Asian eyes: the Singapore Corneal Transplant Study. Ophthalmology 2008;115(6):975–982. 4. Yidiz EH, Hoskins E, Fram N, et al. Third or greater penetrating keratoplasties: indications, survival and visual outcomes. Cornea 2010;29(3):254 –259.
REPLY
The study population that was used for this analysis was taken from our previous publication, and for uniformity, 1 graft per patient was selected for analysis. The study provides a continuity of the same cohort being followed up regarding postoperative risk factors, including the preoperative risk factors. It would not be right to include the last graft in eyes with multiple grafts, as suggested by the authors, in the present study. Choosing only the last graft with multiple grafts calls for another study on selected grafts, and the interpretation will have to be taken into account in a different perspective. This will be taken as a worst-case scenario only where the purpose of the study is determining the risk factors among the worstcase scenario. The hazard ratio (HR) for preoperative inflammation (P ⫽ .03; HR, 1.5; 95% confidence interval, 1.03 to 2.2), perforation (P ⬍ .01; HR, 3.4; 95% confidence interval, 1.9 to 5.7), and recurrence of primary disease (P ⫽ .002; HR, 6.6; 95% confidence interval, 1.9 to 22.4) is provided in parenthesis beside the individual risk factors. A significantly high HR was noted not only for pseudophakic bullous keratopathy and aphakic bullous keratopathy, but also for other indications for penetrating keratopathy, and because this was depicted in the Table, it was not elaborated on further. It implies that primary diagnosis has a strong influence on graft survival, as discussed in the article. Again, the follow-up was the same as described in our earlier publication, and the median and range has been provided additionally. We thank you again for the kind interest. ARUNDHATI ANSHU LAURENCE LIM H. L. A. MYINT HTOON DONALD TAN
WE THANK DR FERNANDES AND HER TEAM FOR THEIR INTER-
est in our article.1 The purpose of our study was to evaluate and assess the role of potential postoperative risk factors in long-term graft survival, and although we agree that examining a more uniform group of indications for keratoplasty would have been an option, we decided specifically to include optical, tectonic, and therapeutic indications because this was in keeping with our findings in an earlier submission looking at preoperative and intraoperative risk factors, to enable direct correlations to be drawn.2 We looked at the same group of patients and for consistency, included all 3 indications to compare risk factors. The same study population that has been described in earlier publication2 was used in this study, and this was stated in the manuscript in the Methods, in which we provided the mean follow-up duration, 36.8 ⫾ 35.5 months (median, 25.07 months; range, up to 173.8 months). Please see the additional Table detailing sample size of the postoperative risk factors by year. You may also wish to know that Kaplan-Meier survival analysis plots for all significant risk factors were generated, but specifically were not included in the article for brevity, because they already were described in the text. Plots on allograft rejection and glaucoma surgery were included to show the influence of these factors on graft survival. VOL. 152, NO. 2
Singapore, Republic of Singapore
REFERENCES
1. Anshu A, Lim LH, Htoon HLA, Tan DT. Postoperative risk factors influencing corneal graft survival in the Singapore corneal transplant study. Am J Ophthalmol 2011;151(3):257– 262. 2. Tan DTH, Janardhanan P, Zhou H, et al. Penetrating keratoplasty in Asian eyes: the Singapore corneal transplant study. Ophthalmology 2008;115(6):975–982.
Descemet Stripping Automated Endothelial Keratoplasty in Failed Penetrating Keratoplasty Patients EDITOR: WE READ THE RECENT RESULTS OF “DESCEMET STRIPPING
Automated Endothelial Keratoplasty under Failed Penetrating Keratoplasty,” written by Straiko and associates,1
CORRESPONDENCE
323
with great interest. They describe modifying their standard Descemet stripping automated endothelial keratoplasty (DSAEK) surgical technique by careful stromal scraping to avoid the graft– host interface and purposely sizing the DSAEK donor tissue to fit inside the diameter of the penetrating keratoplasty (PK). With this technique, only 1 graft dislocation (5.9%) was noted. Price and Price reported a retrospective series of 7 eyes, with visual improvement in 6 of 7 cases and a partial donor detachment in 1 case.2 Covert and Koenig published a retrospective series of 7 eyes with visual improvement in most eyes, but 2 of 7 primary graft failures and donor dislocation in 3 of 7 eyes.3 Lee and associates retrospectively reported on 8 patients, most of whom had improved vision, despite 3 of 8 requiring repositioning or rebubbling and 1 primary graft failure.4 Clements and associates report a large multicenter collaboration with 97 eyes and a 31% dislocation rate, but only 2% primary graft failure.5 Despite generally improved graft clarity and visual outcomes, considerable variation in surgical technique and incidence of complications, including dislocation and graft failure, exist. At our institution, 22 consecutive eyes of 19 patients treated with DSAEK after failure of previous PK by 2 surgeons were reviewed. The mean preoperative best visual acuity at the time of surgery was worse than 20/180. The mean follow-up period was 8.2 ⫾ 7.5 months (range, 1 to 26 months). All except 2 cases in our series had improved visual outcomes, with 8 cases (36.3%) achieving a best visual acuity of 20/40 or better and 15 (68.2%) achieving a best visual acuity of 20/60 or better. Only 1 dislocation (4.5%) was noted, which required rebubbling with subsequent reattachment. All our grafts were punched using a trephine the same measured diameter of the failed PK. Descemet membrane was not removed or scraped in any case in our series, but all cases had venting incisions. We used a glide-and-pulling technique through a 4.5-mm limbal clear corneal incision. Although we attempted to produce identically sized grafts, intraoperative variability in attempted versus achieved cut diameter was noted, and some PK– host overlap of the DSAEK tissue was noted in many cases. DSAEK after failed PK demonstrated favorable clinical results in our series. Graft– host interfaces were well apposed, as demonstrated clinically and on optical coherence tomography, although unlike Straiko and associates, we did not use preoperative optical coherence tomography to aid in determining DSAEK graft size. Of 22 cases evaluated, only 1 had a significant complication, developing an acute allograft rejection, although is unclear whether this complication was related to the surgical method of DSAEK. All other cases in our series had clear grafts, with no evidence of decompensation. Our dislocation and failure rates are similar to the those in the series reported by Straiko and associates, despite significant differences in technique. 324
AMERICAN JOURNAL
Although the results of DSAEK after failed PK are promising, longer follow-up and prospective comparisons may be helpful in determining the relative value of different surgical methods to treat endothelial failure in selected PK patients. MARK D. MIFFLIN MARCUS C. NEUFFER BRIAN E. ZAUGG SHAMEEMA SIKDER MAJID MOSHIRFAR
Salt Lake City, Utah
REFERENCES
1. Straiko MD, Terry MA, Shamie N. Descemet stripping automated endothelial keratoplasty under failed penetrating keratoplasty: a surgical strategy to minimize complications. Am J Ophthalmol 2011;151(2):233–237. 2. Price FW, Price MO. Endothelial keratoplasty to restore clarity to a failed penetrating graft. Cornea 2006;25(8):895– 899. 3. Covert DJ, Koenig SB. Descemet stripping and automated endothelial keratoplasty (DSAEK) in eyes with failed penetrating keratoplasty. Cornea 2007;26(6):692– 696. 4. Lee BS, Stark WJ, Jun AS. Descemet-stripping automated endothelial keratoplasty: a successful alternative to repeat penetrating keratoplasty. Clinical and Experimental Ophthalmology 2011;39(3):195–200. 5. Clements JL, Bouchard CS, Lee WB, et al. Retrospective review of graft dislocation rate associated with Descemet stripping automated endothelial keratoplasty after primary failed penetrating keratoplasty. Cornea 2010;30(4):414 – 418.
REPLY WE THANK DR MIFFLIN AND ASSOCIATES FOR THEIR LET-
ter, and we commend them on their excellent results in their series of Descemet stripping automated endothelial keratoplasty (DSAEK) under failed penetrating keratoplasty (PK), using a technique that retains recipient bed Descemet membrane and that uses a same size donor. It is obvious that there is more than one way to have successful attachment of donor tissue for this unique cohort of patients. We wish to point out, however, that the 1 case of dislocation in our series was the result of postoperative hypotony in a severely complex eye, not a routine DSAEK under PK. It was the hypotony that caused the detachment, independent of whether the eye had a prior PK. Removing the factor of hypotony from the series yields a 0% detachment rate, which is what we have achieved now in our current consecutive series of 24 cases of DSAEK under PK. Did Mifflin and associates’ series have a similar situation for their dislocated case, or was it a routine endothelial keratoplasty under PK case? OF
OPHTHALMOLOGY
AUGUST
2011
Visakhapatnam, Andhra Pradesh, India
REFERENCES
1. Anshu A, Lim LS, Htoon HM, Tan DT. Postoperative risk factors influencing corneal graft survival in the Singapore Corneal Transplant Study. Am J Ophthalmol 2011;151(3): 442– 448. 2. Sharma N, Sachdev R, Jhanji V, et al. Therapeutic keratoplasty for microbial keratitis. Curr Opin Ophthalmol 2010; 21(4):293–300. 3. Tan DT, Janardhanan P, Zhou H, et al. Penetrating keratoplasty in Asian eyes: the Singapore Corneal Transplant Study. Ophthalmology 2008;115(6):975–982. 4. Yidiz EH, Hoskins E, Fram N, et al. Third or greater penetrating keratoplasties: indications, survival and visual outcomes. Cornea 2010;29(3):254 –259.
REPLY
The study population that was used for this analysis was taken from our previous publication, and for uniformity, 1 graft per patient was selected for analysis. The study provides a continuity of the same cohort being followed up regarding postoperative risk factors, including the preoperative risk factors. It would not be right to include the last graft in eyes with multiple grafts, as suggested by the authors, in the present study. Choosing only the last graft with multiple grafts calls for another study on selected grafts, and the interpretation will have to be taken into account in a different perspective. This will be taken as a worst-case scenario only where the purpose of the study is determining the risk factors among the worstcase scenario. The hazard ratio (HR) for preoperative inflammation (P ⫽ .03; HR, 1.5; 95% confidence interval, 1.03 to 2.2), perforation (P ⬍ .01; HR, 3.4; 95% confidence interval, 1.9 to 5.7), and recurrence of primary disease (P ⫽ .002; HR, 6.6; 95% confidence interval, 1.9 to 22.4) is provided in parenthesis beside the individual risk factors. A significantly high HR was noted not only for pseudophakic bullous keratopathy and aphakic bullous keratopathy, but also for other indications for penetrating keratopathy, and because this was depicted in the Table, it was not elaborated on further. It implies that primary diagnosis has a strong influence on graft survival, as discussed in the article. Again, the follow-up was the same as described in our earlier publication, and the median and range has been provided additionally. We thank you again for the kind interest. ARUNDHATI ANSHU LAURENCE LIM H. L. A. MYINT HTOON DONALD TAN
WE THANK DR FERNANDES AND HER TEAM FOR THEIR INTER-
est in our article.1 The purpose of our study was to evaluate and assess the role of potential postoperative risk factors in long-term graft survival, and although we agree that examining a more uniform group of indications for keratoplasty would have been an option, we decided specifically to include optical, tectonic, and therapeutic indications because this was in keeping with our findings in an earlier submission looking at preoperative and intraoperative risk factors, to enable direct correlations to be drawn.2 We looked at the same group of patients and for consistency, included all 3 indications to compare risk factors. The same study population that has been described in earlier publication2 was used in this study, and this was stated in the manuscript in the Methods, in which we provided the mean follow-up duration, 36.8 ⫾ 35.5 months (median, 25.07 months; range, up to 173.8 months). Please see the additional Table detailing sample size of the postoperative risk factors by year. You may also wish to know that Kaplan-Meier survival analysis plots for all significant risk factors were generated, but specifically were not included in the article for brevity, because they already were described in the text. Plots on allograft rejection and glaucoma surgery were included to show the influence of these factors on graft survival. VOL. 152, NO. 2
Singapore, Republic of Singapore
REFERENCES
1. Anshu A, Lim LH, Htoon HLA, Tan DT. Postoperative risk factors influencing corneal graft survival in the Singapore corneal transplant study. Am J Ophthalmol 2011;151(3):257– 262. 2. Tan DTH, Janardhanan P, Zhou H, et al. Penetrating keratoplasty in Asian eyes: the Singapore corneal transplant study. Ophthalmology 2008;115(6):975–982.
Descemet Stripping Automated Endothelial Keratoplasty in Failed Penetrating Keratoplasty Patients EDITOR: WE READ THE RECENT RESULTS OF “DESCEMET STRIPPING
Automated Endothelial Keratoplasty under Failed Penetrating Keratoplasty,” written by Straiko and associates,1
CORRESPONDENCE
323
with great interest. They describe modifying their standard Descemet stripping automated endothelial keratoplasty (DSAEK) surgical technique by careful stromal scraping to avoid the graft– host interface and purposely sizing the DSAEK donor tissue to fit inside the diameter of the penetrating keratoplasty (PK). With this technique, only 1 graft dislocation (5.9%) was noted. Price and Price reported a retrospective series of 7 eyes, with visual improvement in 6 of 7 cases and a partial donor detachment in 1 case.2 Covert and Koenig published a retrospective series of 7 eyes with visual improvement in most eyes, but 2 of 7 primary graft failures and donor dislocation in 3 of 7 eyes.3 Lee and associates retrospectively reported on 8 patients, most of whom had improved vision, despite 3 of 8 requiring repositioning or rebubbling and 1 primary graft failure.4 Clements and associates report a large multicenter collaboration with 97 eyes and a 31% dislocation rate, but only 2% primary graft failure.5 Despite generally improved graft clarity and visual outcomes, considerable variation in surgical technique and incidence of complications, including dislocation and graft failure, exist. At our institution, 22 consecutive eyes of 19 patients treated with DSAEK after failure of previous PK by 2 surgeons were reviewed. The mean preoperative best visual acuity at the time of surgery was worse than 20/180. The mean follow-up period was 8.2 ⫾ 7.5 months (range, 1 to 26 months). All except 2 cases in our series had improved visual outcomes, with 8 cases (36.3%) achieving a best visual acuity of 20/40 or better and 15 (68.2%) achieving a best visual acuity of 20/60 or better. Only 1 dislocation (4.5%) was noted, which required rebubbling with subsequent reattachment. All our grafts were punched using a trephine the same measured diameter of the failed PK. Descemet membrane was not removed or scraped in any case in our series, but all cases had venting incisions. We used a glide-and-pulling technique through a 4.5-mm limbal clear corneal incision. Although we attempted to produce identically sized grafts, intraoperative variability in attempted versus achieved cut diameter was noted, and some PK– host overlap of the DSAEK tissue was noted in many cases. DSAEK after failed PK demonstrated favorable clinical results in our series. Graft– host interfaces were well apposed, as demonstrated clinically and on optical coherence tomography, although unlike Straiko and associates, we did not use preoperative optical coherence tomography to aid in determining DSAEK graft size. Of 22 cases evaluated, only 1 had a significant complication, developing an acute allograft rejection, although is unclear whether this complication was related to the surgical method of DSAEK. All other cases in our series had clear grafts, with no evidence of decompensation. Our dislocation and failure rates are similar to the those in the series reported by Straiko and associates, despite significant differences in technique. 324
AMERICAN JOURNAL
Although the results of DSAEK after failed PK are promising, longer follow-up and prospective comparisons may be helpful in determining the relative value of different surgical methods to treat endothelial failure in selected PK patients. MARK D. MIFFLIN MARCUS C. NEUFFER BRIAN E. ZAUGG SHAMEEMA SIKDER MAJID MOSHIRFAR
Salt Lake City, Utah
REFERENCES
1. Straiko MD, Terry MA, Shamie N. Descemet stripping automated endothelial keratoplasty under failed penetrating keratoplasty: a surgical strategy to minimize complications. Am J Ophthalmol 2011;151(2):233–237. 2. Price FW, Price MO. Endothelial keratoplasty to restore clarity to a failed penetrating graft. Cornea 2006;25(8):895– 899. 3. Covert DJ, Koenig SB. Descemet stripping and automated endothelial keratoplasty (DSAEK) in eyes with failed penetrating keratoplasty. Cornea 2007;26(6):692– 696. 4. Lee BS, Stark WJ, Jun AS. Descemet-stripping automated endothelial keratoplasty: a successful alternative to repeat penetrating keratoplasty. Clinical and Experimental Ophthalmology 2011;39(3):195–200. 5. Clements JL, Bouchard CS, Lee WB, et al. Retrospective review of graft dislocation rate associated with Descemet stripping automated endothelial keratoplasty after primary failed penetrating keratoplasty. Cornea 2010;30(4):414 – 418.
REPLY WE THANK DR MIFFLIN AND ASSOCIATES FOR THEIR LET-
ter, and we commend them on their excellent results in their series of Descemet stripping automated endothelial keratoplasty (DSAEK) under failed penetrating keratoplasty (PK), using a technique that retains recipient bed Descemet membrane and that uses a same size donor. It is obvious that there is more than one way to have successful attachment of donor tissue for this unique cohort of patients. We wish to point out, however, that the 1 case of dislocation in our series was the result of postoperative hypotony in a severely complex eye, not a routine DSAEK under PK. It was the hypotony that caused the detachment, independent of whether the eye had a prior PK. Removing the factor of hypotony from the series yields a 0% detachment rate, which is what we have achieved now in our current consecutive series of 24 cases of DSAEK under PK. Did Mifflin and associates’ series have a similar situation for their dislocated case, or was it a routine endothelial keratoplasty under PK case? OF
OPHTHALMOLOGY
AUGUST
2011