[Complications of Descemet Stripping Automated Endothelial Keratoplasty (DSAEK)]

Cost Burden of Endothelial Keratoplasty in Fuchs Endothelial Dystrophy: Real-World Analysis of a Commercially Insured US Population (2014–2019)

Purpose

To assess the incremental burden of corneal transplant surgery for US commercially insured patients with Fuchs endothelial corneal dystrophy (FECD) treated with endothelial keratoplasty (EK) compared to controls.

Methods

The study design was retrospective cohort using IBM^® MarketScan^® claims (January 2014–September 2019) and included EK-treated (N=1562) and control patients (N=23,485) having ≥12 months’ enrollment before and after diagnosis, who were subsequently matched on select characteristics. The index date was the beginning of the pre-operative period (3 months before EK); synthetic EK index was assigned for controls. All-cause, eye-disease, and complication-related healthcare resource utilization (HCRU) and costs were compared up to 36 months post index. For a small subset of patients, patient data were linked to the Health and Productivity Management supplemental database, which integrates data on productivity loss and disability payments.

Results

Matched cohorts included 804 EK-treated and 1453 controls with average age 65.7 years, 1383 (61%) female. Over 12 months of follow-up, all-cause ($41,199 vs $20,222, p<0.001) and eye-disease related costs ($22,951 vs $1389, p<0.001) were higher among EK-treated patients than controls. The cost differential increased additionally by $1000–$2000 per annum by 36 months of follow-up. While balanced at baseline, over follow-up EK-treated patients had higher prevalence of glaucoma, elevated intraocular pressure, cataract, cataract surgery, diagnosis of cornea transplant rejection, retinal edema. By 36 month of follow-up, EK-treated patients had 9 more short-term disability days, resulting in $2992 additional burden of disability payments.

Conclusion

This study found a higher cost burden among FECD patients receiving EK treatment versus those who did not. With a shift in management of FECD, cost burden estimates generated in this study could serve as an important benchmark for future studies.

Fate of endothelial cells after intrastromal implantation of Descemet's membrane-endothelial cell tissue

In non-Descemet Stripping Automated Endothelial Keratoplasty (nDSAEK), the host DM and endothelium are not removed surgically before the introduction of the posterior lamellar graft; the result is that the patient has both the healthy donor endothelium and the diseased or residual host endothelium. Conversely, DSAEK tissues, that are inserted with inverted polarity (upside down), do not survive and the graft fails. While the mechanism of endothelial cell transplantation is clear, the fate of the endothelial cells retained between two stromal interfaces and their physiological role, if any, is not well understood. The aim of our study was therefore to evaluate the viability of a healthy endothelial-Descemet's membrane (EDM) graft after the insertion into a stromal pocket of a recipient donor cornea. Research corneas (n = 52) were divided into three groups: Group A, where an EDM (obtained from another cornea) with good endothelium was inserted in a stromal pocket endothelium side down; Group B, consisting of control corneas with a stromal pocket but without EDM insertion; and Group C, pre-stripped membranes resting on their stroma (not in a stromal pocket). The tissues were preserved in tissue culture medium for 21 days at 31 °C. Parameters including viability of endothelial cells, expression of tight junctions (ZO-1) and thickness were evaluated. After 21 days, all the membranes inserted within the stromal pocket of Group A survived, although an average endothelial cell loss of 30.1% (± 18.10) and a mortality of 10.2% (± 22.86) were recorded. Qualitative analysis using triple staining with Hoechst, ethidium homodimer and calcein AM confirmed the mortality. ZO-1 was expressed where the cells were present, showing good integrity of tight junctions. Group C showed an average endothelial cell loss of 1.9% (± 3.38), a mortality of 0.02% (± 0.07) and a higher expression of ZO-1. An EDM graft with endothelium facing downwards can survive in a stromal pocket for at least 3 weeks, with an overall cell mortality of 30%. Further studies are needed to evaluate the possible outcomes of the insertion of a healthy intrastromal EDMs with reverse polarity and in edematous corneas.

[Effect of donor graft characteristics on clinical outcomes in Descemet stripping automated endothelial keratoplasty (DSAEK)]

INTRODUCTION

The purpose of our study was to evaluate the progression of lamellar corneal grafts after endothelial keratoplasty by Descemet stripping automated endothelial keratoplasty (DSAEK) and the effect of their characteristics on the clinical and functional results.

MATERIALS AND METHODS

This was a prospective study in which 74 patients who had undergone endothelial keratoplasty by DSAEK were included. The corneal grafts were obtained from a French tissue bank and were delivered in a preservation medium containing a deturgescent agent (Corneajet^® or Stemalpha 3^®). Pachymetry of the corneal graft was measured ex vivo by ultrasonic pachymetry prior to dissection, then after the 1st or 2^nd cut as necessary. Corrected visual acuity in logMAR, total graft pachymetry, measured by anterior segment OCT (Spectralis^® HRA+SDOCT, Heidelberg engineering, Inc., Heidelberg, Germany) and corneal density (Pentacam^®, Oculus, Inc., Wetzlar, Germany) were obtained for each patient preoperatively, at D5, M1, M3, M6, M9 and M12.

RESULTS

Overall, 74 corneal grafts, from donors of mean age 69.7±13.3 years (37 to 92 years) were transplanted into 67 patients aged 70.3±12.1 years. Predissection pachymetry was statistically significantly thicker in the case of short deturgescence time (r=-0.383, P=0.001). For the same deturgescence time, predissection pachymetry was statistically significantly thicker in the Stemalpha 3^® medium (691±89μm for Corneajet^® vs. 760±100μm for Stemalpha 3^®, P=0.01), with the same final pachymetry (168±31μm vs. 166±25μm, P=0.833). Graft pachymetry and total corneal pachymetry decreased significantly between the preoperative measurement and M12 (168±29μm vs. 92±57μm, P=0.0008 et 665±124μm vs. 566±73μm, P=0.027 respectively). Preoperative endothelial cell density (2938±418 cells/mm²) did not correlate with postoperative visual acuity. There was a positive correlation between visual acuity at D5 and donor age (r=0.3, P=0.04). Postoperative visual acuity correlated positively with preoperative visual acuity (P<0.05). Corneal densitometry was statically higher than normal postoperative densitometry. Corneal density at M1 correlated positively with time since obtaining the donor tissue (r=0.373, P=0.043). There was no significant difference between the sub-groups of over or under 130μm. Seven patients experienced graft failure with no statistically significant graft risk factor.

DISCUSSION

The preservation medium affects predissection pachymetry with no consequence on clinical results. In our study, preoperative visual acuity and donor age were correlated with visual acuity after DSAEK.

CONCLUSION

Although donor age was associated with better visual acuity at D5, the other donor characteristics had no effect on clinical results.