Survival of corneal grafts from donors supported by mechanical ventilation

Topical Corticosteroids and Fungal Keratitis: A Review of the Literature and Case Series

The management of fungal keratitis is complex since signs and symptoms are subtle and ocular inflammation is minimal in the preliminary stages of infection. Initial misdiagnosis of the condition and consequent management of inflammation with corticosteroids is a frequent occurrence. Topical steroid use is considered to be a principal factor for development of fungal keratitis. In this review, we assess the studies that have reported outcomes of fungal keratitis in patients receiving steroids prior to diagnosis. We also assess the possible rebound effect present when steroids are abruptly discontinued and the clinical characteristics of three patients in this particular clinical scenario. Previous reports and the three clinical descriptions presented suggest that in fungal keratitis, discontinuing topical steroids can induce worsening of clinical signs. In these cases, we recommend to slowly taper steroids and continue or commence appropriate antifungal therapy.

Intensive care unit time and prolonged enucleation to processing interval are associated with donor cornea contamination

PURPOSE

To determine donor cornea contamination rate and to determine factors associated with cornea contamination. To assess the effect of hospitalization, intensive care unit (ICU) time, and antibiotic use on corneal contamination rate. To determine the spectrum of the contaminating microorganisms.

METHODS

The contamination rate of 212 corneas, obtained by enucleation from April 2014 to January 2015 in a single eye bank, was assessed retrospectively according to age, sex, cause of death, systemic antibiotic use, hospitalization time, ICU time, mechanical ventilation (MV), death to enucleation interval (DEI), enucleation to processing interval (EPI), and corneal epithelial exposure grading. The relative risk (RR) and adjusted RR with a 95% confidence interval were calculated using IBM-SPSS 20.0.

RESULTS

The contamination rate was 35.6% (n = 75). On multivariate analysis, ICU stay of 4 days or longer and enucleation to processing interval (EPI) greater than 7.4 h (RR 1.58, CI 0.96-2.60, P = 0.06) were associated with donor cornea contamination. Corneal contamination risk was highest from 4 to 6 days at the ICU (RR 3.40, CI 1.54-7.51, P < 0.01) and decreased after 7 days (RR 2.22, CI 1.00-4.93, P = 0.05). Coagulase-negative Staphylococcus was the most common isolated bacteria (69.6%). The frequency of gentamicin-resistant bacteria was higher among patients who stayed 4 days or longer at the ICU.

CONCLUSION

Patients staying at the intensive care unit 4 days or longer showed increased risk of corneal contamination. This is an important result to consider further indication for cornea donation.

The Effect of Chronic Pulmonary Disease and Mechanical Ventilation on Corneal Donor Endothelial Cell Density and Transplant Suitability

PURPOSE

To determine how chronic obstructive pulmonary disease (COPD) and mechanical ventilation time affect corneal donor endothelial cell density (ECD) and transplant suitability.

DESIGN

Retrospective cohort study.

METHODS

Setting: Institutional.

STUDY POPULATION

Total of 39 679 cornea donor eyes from SightLife Eye Bank between 2012 and 2016. Demographics, death-to-preservation time, ECD, lens status, medical history, time on mechanical ventilation, and suitability for transplantation were included.

MAIN OUTCOME MEASURES

ECD and transplant suitability.

RESULTS

Mean ECD was 2733 cells/mm². Mean age was 59 years. COPD affected 34.2% of donors. Mechanical ventilation was required in 35% of donors. Mean ventilation time was 1.3 days. After controlling for covariates, COPD was not found to be associated with poor transplant suitability (P = .22). Ventilation >7 days was associated with poor transplant suitability (P = .04). Donors with COPD and donors who were mechanically ventilated exhibited lower cell counts (P < .001, P < .01, respectively). Longer ventilation led to reduced endothelial cell density: ventilation time >7 days (-46.5 cells/mm², P < .001) and >30 days (-101.4 cells/mm², P = .02). Limitations of the study included the retrospective nature, dataset obtained from a single eye bank, and medical history documentation completed by eye bank technicians.

CONCLUSIONS

A high proportion of cornea donors have respiratory disease prior to donation. Ventilation time >7 days affected transplant suitability but the presence of COPD did not. Donors with COPD and donors who were mechanically ventilated had reduced cell counts. Longer ventilation times lead to increased cell loss. The presence of respiratory disease may affect tissue oxygenation and endothelial cell health.

Infectious Disease Transmission through Cell, Tissue, and Organ Transplantation: Reducing the Risk through Donor Selection

The incidence of cell transplant-transmitted infection is unknown and can only be inferred from prospective studies–that have not yet been performed and reported. The possibility of donor-to-recipient disease transmission through cell transplant therapy can be considered by reviewing the risk associated with other transplanted tissues and organs. Viral, bacterial, and fungal infections have been transmitted via transplantation of organs, tissue allografts such as bone, skin, cornea, and heart valves, and cells such as islets, hematopoietic stem cells, and semen. Several types of protozoan and worm parasites have been transferred via organ transplants. Bone allografts have transmitted hepatitis, tuberculosis, and human immunodeficiency virus (HIV-1). Corneas have transmitted rabies, Creutzfeldt-Jakob disease (CJD), hepatitis B (HBV), cytomegalovirus (CMV), herpes simplex virus (HSV), bacteria, and fungi. Heart valves have been implicated in transmitting tuberculosis and hepatitis B. HIV-1 and CMV seroconversion has been reported in patients receiving skin from seropositive donors. CJD has been transmitted by dura and pericardium transplants. Over the past several years, improvements in donor screening criteria, such as excluding potential donors with infection and those with behaviors risky for HIV-1 and hepatitis infection, and introduction of new donor blood tests have greatly reduced the risk of HIV-1 and hepatitis and may have nearly eliminated the risk of tuberculosis and CJD. Prior to use, many tissues are exposed to antibiotics, disinfectants, and sterilants, which further reduce or remove the risk of transmitted disease. Because organs, cells, and some tissue grafts cannot be subjected to sterilization steps, the risk of infectious disease transmission remains and thorough donor screening and testing is especially important.

Therapeutic dilemma in fungal keratitis: administration of steroids for immune rejection early after keratoplasty

PURPOSE

To investigate the timing and dosage of topical corticosteroid use after keratoplasty for fungal keratitis, and to evaluate the results with regard to anterior segment inflammation, immune rejection, and fungal recurrence.

METHODS

This prospective observational study included a total of 244 patients (244 eyes) who underwent penetrating keratoplasty (PK, 118 patients) or lamellar keratoplasty (LK, 126 patients) for fungal keratitis at the Shandong Eye Hospital between January 2009 and April 2014. Topical administration of steroid eye drops was initiated at 1 week after surgery. Changes in ocular inflammation before and after steroid use, percentages of eyes with fungal recurrence and immune rejection, and the relationship between the timing of local administration of steroids and therapeutic anti-inflammatory effects after keratoplasty were evaluated. The follow-up period was 6 months.

RESULTS

Anterior segment inflammation was aggravated within 1 week after surgery, with ocular pain, photophobia, redness, and tearing, but was controlled at 7.51 ± 1.76 days after steroid use. Fungal keratitis recurred in three eyes (1.23 %) at 3 to 5 days after administration of corticosteroids, including two eyes receiving PK and one eye receiving LK. Recurrence was controlled with antifungal medications. Allograft rejection occurred in eight (6.78 %) of 118 patients treated by PK, but did not occur in patients treated by LK.

CONCLUSIONS

Initiating the use of topical corticosteroids in patients with fungal keratitis 1 week after keratoplasty can aid in rapid control of anterior segment inflammation and reduction of immune rejection, with no increase in the rate of fungal recurrence.

Bacterial infection transmitted by human tissue allograft transplantation

Bacterial contamination of tissue allografts obtained from cadaveric donors has been a serious cause of morbidity and mortality in recipients. Recent cases of fatal and nonfatal bacterial infections in recipients of contaminated articular cartilage (distal femur) and tendon allografts have called attention to the importance of avoiding tissue donors suspected of carrying infectious disease, of not processing donated tissue carrying virulent bacteria, the occurrence of falsely negative final sterility tests, and the need to sterilize tissues. These cases demonstrated that contamination can arise from an infected donor, during tissue removal from cadaveric donors, from the processing environment, and from contaminated supplies and reagents used during processing. Final sterility testing can be unreliable, especially when antibiotics remain on tissues. There is an increasing need for control of microbial contamination in tissue banks, and sterilization of tissue allografts should be recommended whenever possible.

The Incidence of Fungal Keratitis and Endophthalmitis Following Penetrating Keratoplasty

PURPOSE

To determine the incidence of postkeratoplasty fungal endophthalmitis and keratitis at the New York Eye and Ear Infirmary. To determine whether there is a relationship between culture-positive corneoscleral donor material and postoperative infection.

METHODS

The microbiologic records of corneoscleral donor rims submitted for culture following penetrating keratoplasty at the New York Eye and Ear Infirmary between January 1998 and January 2003 were reviewed. The incidence of rim cultures positive for fungi was tabulated. Clinical outcome measures were recorded for each patient receiving corneal donor tissue.

RESULTS

Of 2466 donor corneoscleral rims cultured during the study period, 344 were positive for microbial growth (13%). Of those rims with positive cultures, 28 (8.6%) were positive for fungus. All fungi cultured were Candida species. Four of the 28 recipient eyes (14%) who received contaminated donor material went on to develop postkeratoplasty fungal infections. There were no cases of fungal infection in any postkeratoplasty patients in the absence of contaminated donor rims during the study period. Overall, there was a 0.16% incidence of fungal infection (4/2466) following penetrating keratoplasty. There were 18 positive donor rims identified in the first 4 years of the study, but there were 10 cases in the last 10 months of the study.

CONCLUSIONS

The overall incidence of fungal infection following penetrating keratoplasty is low, but all cases in our study were associated with positive rim cultures. Whether prophylactic antifungal therapy would be of any benefit in the presence of a positive corneoscleral rim culture has not yet been determined.

The effects of donor age and cause of death on corneal graft survival

The Ontario Corneal Recipient Registry followed 299 recipients of 326 corneal transplants performed between October 1985 and October 1987. This report describes the joint effects of donor age and cause of death on subsequent graft survival in these procedures up to two years after surgery. Cox regression analysis established that grafts from donors dying of injury experienced half the risk of graft failure of those from donors dying of heart disease or other natural causes (P less than 0.05). Although donor age differed substantially between these causes of death, controlling for donor age did not alter the association. There were no statistically or clinically significant differences in graft survival associated with either donor age or recipient age. These results suggest that the health of the donor and the circumstances surrounding death may influence the quality of corneal tissue, and deserve more attention and detailed study.

Diseases potentially transmitted through corneal transplantation

Transmission of donor disease to the corneal graft recipient appears to be a rare event. Nevertheless, the subject merits careful attention because of the broad spectrum of diseases these cases represent, the potential for transmission of other disorders, and the difficulties in diagnosis they pose. Infections, neoplastic diseases, and corneal disorders may be acquired by corneal transplantation. Very serious are viral infections, but only rabies, Creutzfeldt-Jakob disease, and hepatitis B have had documented transmission. Bacterial and fungal infections are a clear hazard to the graft. On rare occasions, the recipient has died. Although the transmission of local corneal disorders and dystrophies has yet to be documented, the potential seems clear, particularly with tissue from young donors where evidence for dystrophies, such as keratoconus and Fuchs' dystrophy, has yet to appear. Fortunately, in the United States, screening techniques appear to be largely effective in detecting donors who harbor diseases that are potentially transmittable.

Corneal preservation

Significant advances in corneal preservation have been made over the past decade. The introduction of chondroitin sulfate-containing media for use at 4 degrees C allows storage of corneas for up to ten days prior to transplantation. Organ culture techniques have also been improved with the addition of chondroitin sulfate. There has been an increase in our understanding of preservation using McCarey-Kaufman medium. Studies have been published that compare these methods and help the clinician decide which method to use based on objective data. Also, our understanding of existing methods of evaluating endothelial viability has increased and new methods have been developed. Finally, the acquired immunodeficiency syndrome is having an increasing effect on eye-banking and the supply of donor corneas.