Incidence, occurrence rate, and characteristics of suture-related corneal infections after penetrating keratoplasty

A Novel Coated Suture Displays Antimicrobial Activity Without Compromising Structural Properties

BACKGROUND

Treated or coated sutures promise to prevent contamination of wounds.

PURPOSE

The purpose of the study was to coat surgical sutures with a new quaternary ammonium silane (QAS) antimicrobial compound at two different application temperatures and then to evaluate the resulting structural, physical, mechanical, and biological properties.

STUDY DESIGN, SETTING, SAMPLE

In vitro and in vivo studies were conducted using male albino Wistar rats approved by the Joint Ethical Committee of IMU and Postgraduate Medical Institute, Lahore. Only suture samples, coated uniformly with verified presence of the compound and of adequate length were used. Samples which were not coated uniformly and with inadequate length or damaged were excluded.

PREDICTOR VARIABLE

Predictor variables were sutures with and without QAS coatings and different temperatures. Sutures were coated with QAS at 0.5 and 1.0% wt/vol using the dip coating technique and sutures with and without QAS coating were tested at 25 and 40 °C temperatures.

MAIN OUTCOME VARIABLE(S)

Outcome variables of structural and physico-mechanical properties of QAS-coated and non-coated sutures were measured using Fourier transform infrared spectroscopy (for structural changes), confocal laser and scanning electron (for diameter changes), and tensile strength/modulus (for mechanical testing). Biologic outcome variables were tested (bacterial viability); macrophage cultures from Wistar rats were tested (M1/M2 polarization detecting IL-6 and IL-10). Macrophage cells were analyzed with CD80+ (M1) and CD163+ (M2). Chemotaxis index was calculated as a ratio of quantitative fluorescence of cells.

COVARIATES

Not applicable.

ANALYSES

Ordinal data among groups were compared using the Wilcoxon Mann-Whitney U test along with the comparison of histological analysis using the Wilcoxon Sign-rank test (P < .05).

RESULTS

Fourier transform infrared spectroscopy peak at 1490 cm-1 confirmed the presence of QAS on suture's surfaces with a significant increase (P < .05) in diameter (0.99 ± 0.5-mm) and weight (0.77 ± 0.02-mg) observed for 1% QAS groups treated at 40 °C. Non-coated samples heated at 25 °C had significantly (P < .05) less diameters (0.22 ± 0.03-mm) and weights (0.26 ± 0.06-mg). Highest tensile strength/modulus was observed for 0.5% QAS-coated samples which also had significantly higher antibacterial characteristics than other sutures (P < .05). QAS-coated sutures significantly increased M1 and M2 markers.

CONCLUSION AND RELEVANCE

QAS coating conferred antibacterial action properties without compromising the physical and mechanical properties of the suture.

Loose suture-related ocular surface inflammation and activation of conjunctiva-associated lymphoid tissue in patients after keratoplasty

The purpose of this study is to evaluate loose suture-related inflammation and activation of conjunctiva-associated lymphoid tissue (CALT) in patients after keratoplasty. The patients who were treated with keratoplasty at the First Affiliated Hospital of Harbin Medical University between 2015 and 2022 were recruited into the study. We evaluated the time and location of loose suture development in patients after keratoplasty. In addition, in vivo confocal microscopy was used to evaluate the activation of CALT and the accumulation of inflammatory cells around loose sutures. Meso Scale Discovery assay detection kits were used to evaluate the inflammatory cytokines in the tears of patients before and after the loose suture was removed. In this study, we collected the information from 212 cases (212 eyes) who had PK (126 eyes) and DALK-treated (86 eyes) for corneal transplantation, including 124 males and 88 females, aged 14-84 years old. The average age was 50.65 ± 16.81 years old. Corneal sutures were more prone to loose at 3 months and 6 months after keratoplasty, and the frequent sites were at 5 and 6 o'clock. An increased number of inflammatory cells could be observed around the loose sutures than normal sutures (P < 0.001). In CALT, the density of diffuse lymphocytes (P < 0.001), follicles (P < 0.001), and parafollicular lymphocytes (P < 0.001) were higher and the central reflection of the follicles (P < 0.001) was stronger when suture loosening happened. The levels of inflammatory cytokines such as IL-1β (P = 0.003), IL-8 (P = 0.012), and TNF-α (P < 0.001) were higher in the tears of the patients with loose sutures. The activation of CALT was partly settled after removing the loose sutures. In conclusion, loose sutures after corneal transplantation can lead to increased infiltration of inflammatory cells, activation of CALT, and increased secretion of inflammatory cytokines in the tears of patients. Regular follow-up to identify and solve the problem in time can avoid suture-related complications.

Suture-related complications after deep anterior lamellar keratoplasty for keratoconus

PURPOSE

The purpose of this study is to determine the incidence of suture-related complications, their risk factors, and effects on the clinical outcomes after deep anterior lamellar keratoplasty (DALK) for keratoconus.

METHODS

In this retrospective, comparative, interventional study, the records of consecutive patients with keratoconus who underwent DALK were reviewed for suture-related complications. Univariate analyses were used to identify risk factors for suture complications. We compared groups with and without suture-related complications to evaluate the effects of these complications on clinical outcomes after DALK.

RESULTS

Of the 633 DALKs, 438 eyes (69.2%) developed suture complications including loose sutures (32.7%), spontaneous suture rupture (30%), sterile suture abscesses (22.8%), suture tract vascularization (16.4%), suture erosion (10.3%), and suture cheese wiring (6.8%). Vernal keratoconjunctivitis increased the incidence of sterile suture infiltration, premature suture loosening, and suture tract vascularization. Loose suture was observed more commonly in larger graft size, while spontaneous suture rupture was associated with late suture removal. There was no statistically significant difference in postoperative outcomes including visual acuity, refraction, graft rejection, and failure in eyes with and without suture complications. However, suture-related complications were directly associated with sight-threatening ocular morbidities, including graft rejection (39 eyes), ulcer (1 eye), and failure (2 eyes).

CONCLUSION

Suture-related complications frequently occurred after DALK for keratoconus. Ocular surface inflammation, large grafts, and late suture removal increased the risk of suture-related complications. While these complications had no negative impact on clinical outcomes in the majority of cases, some of them led to sight-threatening morbidity, underlining the importance of early diagnosis and treatment.

Twelve-Month Clinical and Histopathological Performance of a Novel Synthetic Cornea Device in Rabbit Model

Purpose

To report the biological stability and postoperative outcomes of a second-generation, single-piece, flexible synthetic cornea in a rabbit model.

Methods

Device materials and design were amended to enhance biointegration. Optic skirt design devices were made from compact perfluoroalkoxy alkane with porous expanded polytetrafluoroethylene ingrowth surface overlying the skirt and optic wall. Sixteen devices were implanted into intrastromal pocket in rabbit eyes. Rabbits were randomly assigned to 6- and 12-month follow-up cohorts (n = 8 in each) postoperatively. Monthly examinations and optical coherence tomography assessed cornea-device integration, iridocorneal angle, optic nerve, and retina.

Results

There were no intraoperative complications. All devices were in situ at exit, with clear optics. No retroprosthetic membrane, glaucoma, cataract formation, or retinal detachment was observed. Two rabbits in the 6-month group had mild, focal anterior lamella thinning without retraction adjacent to the optic near tight sutures. Three postoperative complications occurred in the 12-month group. One rabbit diagnosed with endophthalmitis was euthanized on day 228. Mild sterile focal retraction of anterior lamella occurred in two rabbits, which were terminated on days 225 and 315. Light microscopic examination of enucleated globes demonstrated fibroplasia with new collagen deposition into the porous scaffold without significant inflammation, encapsulation, or granuloma formation.

Conclusions

Clinical evaluations, imaging, and histopathological findings indicate favorable outcomes of this synthetic corneal device in a rabbit model. Early feasibility studies in humans are being planned.

Translational Relevance

Favorable 12-month results of the device in rabbits demonstrate vision-restoring potential in corneally blind individuals at high risk of failure with donor keratoplasty.

Femtosecond laser-assisted minimally invasive lamellar keratoplasty for the treatment of advanced keratoconus

BACKGROUND

To evaluate the initial safety and efficacy of femtosecond laser-assisted minimal invasive lamellar keratoplasty (FL-MILK) for advanced keratoconus.

METHODS

Twenty-two patients (22 eyes) with advanced keratoconus were included in this prospective study. All the involved eyes underwent FL-MILK. The femtosecond laser was used to create an intrastromal pocket with a 2.3 mm incision in the recipient cornea. Then a stromal button with a diameter of 9.0 mm and a depth of 200 μm was gently inserted into the intrastromal pocket through the 2.3 mm incision and flattened. No sutures were applied. Follow-up was conducted for 24 months.

RESULTS

Twenty-two patients completed follow-up data for 12 months, 16 patients had 24 months follow-up. No epithelial implantation, infection or allogeneic rejection were observed during the follow-up. Based on baseline values, postoperative 12 months values and postoperative 24 months values, clinical significantly improvement was recorded in corrected distance visual acuity (CDVA) (0.40 ± 0.18 logMAR vs. 0.30 ± 0.12 logMAR and 0.23 ± 0.13 logMAR), the anterior central corneal elevation (29.14 ± 15.33 μm vs. 14.45 ± 13.75μm and 11.38 ± 8.33 μm), and corneal higher-order aberrations (3.536 ± 1.503 vs. 2.761 ± 1.517 and 0.994 ± 0.391). Corneal biomechanical properties in all eyes improved significantly. SP-A1 increased from 48.64 ± 12.87 preoperatively to 87.26 ± 21.01 postoperative 12 months and 88.77 ± 18.26 postoperative 24 months; deformation amplitude (DA) decreased from 1.36 ± 0.15 preoperatively to 1.21 ± 0.12 postoperative 12 months and 1.19 ± 0.19 postoperative 24 months.

CONCLUSIONS

Initial experience suggests that this minimally invasive transplantation may be a feasible option for advanced keratoconus. A larger cohort and longer follow-up are required to validate our results and establish long-term safety and efficacy of the procedure.

Update on Suture Techniques in Corneal Transplantation: A Systematic Review

Effective suturing remains key to achieving successful outcomes in corneal surgery, especially anterior lamellar keratoplasty and full thickness transplantation. Limitations in the technique may result in complications such as wound leak, infection, or high astigmatism post corneal graft. By using a systematic approach, this study reviews articles and conducts content analysis based on update 2020 PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria). The aim of this paper is to summarize the state of the art of corneal suturing techniques for every type of corneal transplant and patient age and also their outcomes regarding astigmatism and complications. Future developments for corneal transplantation will be also discussed. This is important because especially the young surgeon must have knowledge of the implications of every suture performed in order to achieve consistent and predictable post-operative outcomes and also be aware of all the possible complications.

Post-keratoplasty Infectious Keratitis: Epidemiology, Risk Factors, Management, and Outcomes

Post-keratoplasty infectious keratitis (PKIK) represents a unique clinical entity that often poses significant diagnostic and therapeutic challenges. It carries a high risk of serious complications such as graft rejection and failure, and less commonly endophthalmitis. Topical corticosteroids are often required to reduce the risk of graft rejection but their use in PKIK may act as a double-edged sword, particularly in fungal infection. The increased uptake in lamellar keratoplasty in the recent years has also led to complications such as graft-host interface infectious keratitis (IIK), which is particularly difficult to manage. The reported incidence of PKIK differs considerably across different countries, with a higher incidence observed in developing countries (9.2-11.9%) than developed countries (0.02-7.9%). Common risk factors for PKIK include the use of topical corticosteroids, suture-related problems, ocular surface diseases and previous corneal infection. PKIK after penetrating keratoplasty or (deep) anterior lamellar keratoplasty is most commonly caused by ocular surface commensals, particularly Gramme-positive bacteria, whereas PKIK after endothelial keratoplasty is usually caused by Candida spp. Empirical broad-spectrum antimicrobial treatment is the mainstay of treatment for both PKIK, though surgical interventions are required in medically refractory cases (during the acute phase) and those affected by visually significant scarring (during the late phase). In this paper, we aim to provide a comprehensive overview on PKIK, encompassing the epidemiology, risk factors, causes, management and outcomes, and to propose a treatment algorithm for systematically managing this challenging condition.

Ultra-thin, high strength, antibiotic-eluting sutures for prevention of ophthalmic infection

Sutures are applied almost universally at the site of trauma or surgery, making them an ideal platform to modulate the local, postoperative biological response, and improve surgical outcomes. To date, the only globally marketed drug-eluting sutures are coated with triclosan for antibacterial application in general surgery. Loading drug directly into the suture rather than coating the surface offers the potential to provide drug delivery functionality to microsurgical sutures and achieve sustained drug delivery without increasing suture thickness. However, conventional methods for drug incorporation directly into the suture adversely affect breaking strength. Thus, there are no market offerings for drug-eluting sutures, drug-coated, or otherwise, in ophthalmology, where very thin sutures are required. Sutures themselves help facilitate bacterial infection, and antibiotic eye drops are commonly prescribed to prevent infection after ocular surgeries. An antibiotic-eluting suture may prevent bacterial colonization of sutures and preclude patient compliance issues with eye drops. We report twisting of hundreds of individual drug-loaded, electrospun nanofibers into a single, ultra-thin, multifilament suture capable of meeting both size and strength requirements for microsurgical ocular procedures. Nanofiber-based polycaprolactone sutures demonstrated no loss in strength with loading of 8% levofloxacin, unlike monofilament sutures which lost more than 50% strength. Moreover, nanofiber-based sutures retained strength with loading of a broad range of drugs, provided antibiotic delivery for 30 days in rat eyes, and prevented ocular infection in a rat model of bacterial keratitis.

Long-term outcomes of therapeutic penetrating keratoplasty for microbial keratitis in a tertiary care center in Turkey

PURPOSE

To present the long-term results of therapeutic keratoplasty for microbial keratitis in moderate to advanced phases.

METHODS

The medical records of 44 patients who underwent therapeutic keratoplasty for microbial keratitis at the ophthalmology clinic of a training and research hospital between June 2012 and March 2018 were reviewed in this retrospective study.

RESULTS

Of the 65 patients that underwent TPKP, 44 eyes of 44 patients met the inclusion criteria and enrolled in this study. The most commonly found predisposing factor for keratitis was a history of trauma (n = 17, 38.6%), and most of them had occurred with a vegetative matter (n = 14, 31.8%). The most common clinically suspected cause was fungal (n = 17, 38.6%) followed by bacterial (n = 12, 27.3%). In 26 (59.1%) cases, the causative microorganism could not be proved with a microbial culture. The most common causative microorganism was Staphylococcus spp. (n = 4, 9.1%), followed by Fusarium solanii (n = 3, 6.8%). The mean follow-up time was 42 (range 12-54) months. At the last follow-up visit, anatomical success was achieved in 40 (90.9%) cases and the BCVA of more than half of the patients was over 1.0 (logMAR, n = 24, 54.5%). Most commonly seen complication was found to be secondary glaucoma (n = 19, 43.2%), followed by cataracts (n = 9, 34.6%) and graft rejection (n = 12, 27.3%).

CONCLUSIONS

TPKP offers a definitive solution in the management of microbial keratitis with high rates of anatomical and functional success. However, secondary glaucoma is the most common complication after TPKP, which was seen in almost half of the patients.

Femtosecond Laser-Assisted Small Incision Sutureless Intrastromal Lamellar Keratoplasty (SILK) for Corneal Transplantation in Keratoconus

PURPOSE

To describe a femtosecond laser-assisted small incision sutureless intrastromal lamellar keratoplasty in an eye with severe keratoconus and report on the outcome with a 1-year follow-up.

METHODS

A 20-year-old man with a history of keratoconus presented for evaluation at the Tilganga Institute of Ophthalmology, Kathmandu, Nepal. The patient had previously undergone a deep anterior lamellar keratoplasty in the left eye. Examination of the right eye revealed an uncorrected distance visual acuity (UDVA) of counting fingers with a manifest refraction of -5.00 -3.50 × 170, giving a corrected distance visual acuity (CDVA) of 20/80. Thinnest pachymetry was 425 µm and progression of both anterior and posterior corneal elevation tomography and maximum keratometry was noted compared to examination 2 years prior. The VisuMax femtosecond laser (Carl Zeiss Meditec, Jena, Germany) was used to prepare the donor and recipient cornea. The donor graft was inserted into the recipient through the 3-mm small incision. No sutures were applied.

RESULTS

At 2 weeks postoperatively, UDVA was 20/50 with a manifest refraction of -1.00 -5.00 × 145 (20/32). One year postoperatively, UDVA was 20/80 with a manifest refraction of -2.50 -3.50 × 125 (20/40^-2), with the maximum keratometry decreasing from 64.08 to 56.74 diopters.

CONCLUSIONS

This femtosecond laser-assisted sutureless intrastromal corneal transplantation technique may provide an option to improve the quality of vision for some patients with keratoconus, affording a simpler postoperative follow-up course compared to traditional anterior lamellar or full-thickness corneal transplantation. [J Refract Surg. 2019;35(10):663-671.].

Use of affinity allows anti-inflammatory and anti-microbial dual release that matches suture wound resolution

Surgical sutures are vulnerable to bacterial infections and biofilm formation. At the suture site, pain and undesirable, excess inflammation are additionally detrimental to wound healing. The development of a polymerized cyclodextrin (pCD) coated surgical suture introduces the capability to locally deliver both anti-inflammatory and anti-microbial drugs throughout the phases of acute and chronic healing. Local delivery allows for the improvement of wound healing while reducing related systemic side effects and drug resistance. Through testing, it has been shown that the fabrication of our pCD coating minimally affects the suture's mechanical properties. In vitro studies show measurable and consistent drug delivery for nearly 5 weeks. The therapeutic level of this delivery is sufficient to show inhibition of bacterial growth for 4 weeks, and free-radical scavenging (an in vitro anti-inflammatory activity approximation) for 2 weeks. With this pCD coating technique, we maintain clinical performance standards while also introducing a long-term dual delivery system relevant to the wound healing timeframe. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2019.

Current Perspectives of Prophylaxis and Management of Acute Infective Endophthalmitis

Endophthalmitis is an intraocular inflammatory condition which may or may not be caused by infective agents. Noninfectious (sterile) endophthalmitis may be attributable to various causes including postoperative retained soft lens matter or toxicity following introduction of other agents into the eye. Infectious endophthalmitis is further subdivided into endogenous and exogenous. In endogenous endophthalmitis there is hematogenous spread of organisms from a distant source of infection whereas in exogenous endophthalmitis direct microbial inoculation may occur usually following ocular surgery or penetrating eye injury with or without intraocular foreign bodies. Acute infective endophthalmitis is usually exogenous induced by inoculation of pathogens following ocular surgery, open-globe injury and intravitreal injections. More infrequently the infective source is internal and septicemia spreads to the eye resulting in endogenous endophthalmitis. Several risk factors have been implicated including immunosuppression, ocular surface abnormalities, poor surgical wound construction, complicated cataract surgery with vitreous loss and certain types of intraocular lens. Comprehensive guidelines and recommendations on prophylaxis and monitoring of surgical cases have been proposed to minimize the risk of acute endophthalmitis. Early diagnosis and prompt management of infective endophthalmitis employing appropriately selected intravitreal antibiotics are essential to optimize visual outcome.

Clinical outcomes and risk factors for graft failure after deep anterior lamellar keratoplasty and penetrating keratoplasty for macular corneal dystrophy

PURPOSE

The aim of this study was to compare visual acuity, clinical outcomes, complications, and risk factors for graft failure after deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PK) for macular corneal dystrophy.

METHODS

Retrospective comparative case series.

RESULTS

The PK group consisted of 109 eyes of 84 patients and the DALK group consisted of 21 eyes of 20 patients. The mean logarithm of the minimum angle of resolution best-corrected visual acuity at 3 and 12 months was 0.5 versus 0.5 (P = 0.285) and 0.4 versus 0.4 (P = 0.67) in the DALK and PK groups, respectively. There was no significant statistical difference in astigmatism and spherical equivalent between the 2 groups at 12 months. In the PK group, graft rejection that was the most common cause of graft failure was seen in 27 eyes (25%), of which 55% occurred within 1 year. In the DALK group, Descemet membrane microperforation occurred in 5 eyes (24%) intraoperatively, and early postoperative Descemet membrane detachment with double anterior chamber occurred in 9 eyes (43%). Kaplan-Meier estimate of graft survival in PK versus DALK groups were 93% versus 80% at 1 year and 78% versus 70% at 4 years, respectively.

CONCLUSIONS

Visual and refractive outcomes are comparable between DALK and PK groups. DALK was superior to PK in its safety against postoperative complications such as endothelial rejection and secondary glaucoma. Graft failure in DALK was mostly associated with either intraoperative or early postoperative complications. DALK is a viable surgical option in cases with macular corneal dystrophy.

Novel Coating of Surgical Suture Confers Antimicrobial Activity Against Porphyromonas gingivalis and Enterococcus faecalis

BACKGROUND

The oral cavity is colonized by >10(9) bacteria, many of which can increase heart disease risk when seeded into the bloodstream. Most dentoalveolar surgeries require the use of surgical sutures. Suture placement and removal can increase the risk of postoperative infection and bacteremia. The aim of this study is to evaluate the antimicrobial activity of a novel quaternary ammonium compound, K21, when coated on different suture materials.

METHODS

The periodontal pathogen Porphyromonas gingivalis and the endodontic species Enterococcus faecalis were grown to early log phase and inoculated on enriched Brucella blood agar, on which were placed identical lengths of surgical suture (chromic gut, polyester suture, silk, and nylon suture) and control unwaxed dental floss impregnated with K21 at 5%, 10%, 20%, and 25% volume/volume in ethanol vehicle. Controls included the following: 1) sutures treated with vehicle; 2) untreated sutures; and 3) unwaxed floss. Zones of inhibition in millimeters were measured at five randomized sites per suture/floss for each concentration and material used. Mean ± SD of zones of inhibition were calculated, and analysis of variance (P <0.05) was used to determine whether differences were statistically significant.

RESULTS

The results indicate that K21-coated suture at concentrations ranging from 5% to 25%, depending on the type of suture, have antimicrobial activity for P. gingivalis and E. faecalis. Nylon suture coated with K21 at 5%, 10%, 20%, and 25% resulted in zones ranging from 3 to 11 mm. Polyester suture was more effective at lower K21 concentrations with 5% (P = 0.0031), 10% (P = 0.0011), and 20% (P = 0.0002), yielding 7.5, 8.3, and 10.5 mm zones of inhibition. K21-coated silk suture yielded significant zones of inhibition at 25% (P <0.0001), whereas chromic gut was effective at K21 concentrations of 5% (P = 0.0081) and 25% (P <0.0001).

CONCLUSION

It is concluded that K21-coated surgical sutures have antimicrobial activity for bacterial species of direct relevance to postoperative infection and bacteremia.

Eye banking and corneal transplantation communicable adverse incidents: current status and project NOTIFY

PURPOSE

Evidence of the transmission of disease via donor ocular tissue has been demonstrated for adenocarcinoma, rabies, hepatitis B virus, cytomegalovirus, herpes simplex virus, Creutzfeldt-Jakob disease, and a variety of bacterial and fungal infections.

METHODS

Although there is no evidence to date of disease transmission for HIV infection, syphilis, hepatitis C, hepatitis A, tuberculosis, HTLV-1 and -2 infection, active leprosy, active typhoid, smallpox, and active malaria, these entities remain contraindications for transplantation for all eye banks nationally and internationally. The potential sources of contamination include infected donors, during the process of removing tissue from cadaveric donors, the processing environment, and contaminated supplies and reagents used during processing. The transmissions of Herpes simplex virus and HSV via corneal graft have been shown to be responsible for primary graft failure. HSV-1 may also be an important cause of PFG.

RESULTS

The long latency period of some diseases, the emergence of new infectious disease, and the reemergence of others emphasize the need for long-term record maintenance and effective tracing capabilities.

CONCLUSIONS

The standardization of definitions for adverse events and reactions will be necessary to support the prevention and transmission of disease. International classification of a unique identification system for donors will be increasingly important for vigilance and traceability in cross-national exportation of human cells, tissues, and cellular- and tissue-based products. Opportunities for continuous improvement exist as does the need for constant vigilance and surveillance.

Comparative cost-effectiveness analysis of descemet stripping automated endothelial keratoplasty versus penetrating keratoplasty in the United States

PURPOSE

To perform a comparative cost-effectiveness analysis of Descemet stripping automated endothelial keratoplasty (DSAEK) and penetrating keratoplasty (PK) for corneal endothelial disease.

DESIGN

Retrospective cost-effectiveness analysis.

METHODS

This cost-effectiveness analysis was performed from a third-party payer perspective with a 5-year time horizon. Probabilities of outcomes and complications of each of the procedures were calculated based on review of the published literature. A model was constructed to compare the costs and utilities associated with DSAEK and PK. Costs of donor tissue preparation, surgery, follow-up, postoperative complications, and procedures were considered. Utility values were based on quality-adjusted life years associated with visual acuity outcomes. Both costs and utilities were discounted at 3% per year. Sensitivity analyses were performed on key model inputs.

RESULTS

Base case analysis found DSAEK to be less costly compared with PK ($9362 vs $10 239), with greater utility (3.15 vs 2.47 quality-adjusted life years). Sensitivity analyses revealed that even at graft failure rates for DSAEK approaching the rates for PK, DSAEK would still reduce costs. Varying the dislocation rate in our model showed that even at dislocation rates approaching 50%, DSAEK remained less costly. Further, with DSAEK rejection rates as high as 28%, DSAEK would remain a dominant procedure over PK.

CONCLUSIONS

Comparative cost-effectiveness analysis of DSAEK versus PK indicates favorable cost and utility outcomes associated with DSAEK for treatment of corneal endothelial disease. Longer follow-up of DSAEK outcomes will provide more accurate information regarding long-term cost-effectiveness of the procedure.