Penetrating keratoplasty in the United Kingdom: an interim analysis of the corneal transplant follow-up study.
1. Clinical corneal transplantation has been performed for over a century, but many elements leading to a successful outcome have yet to be identified. 2. Because there are limitless supplies of tissue, the supply of corneas need never fall short of demand. Nevertheless, retrieval rates vary widely among regions in the UK due to uneven organization of services. 3. Organ culture of corneas improves the quality of transplanted tissues because it allows time for substandard material to be discarded. The outcome appears to equal other storage methods. 4. Between 1987 and 1991, 4,560 corneal transplants were performed by 428 surgeons at 216 centers in the UK and were registered with CTFS. Of these, 3,213 were evaluable for graft survival, rejection, and other measures of visual outcome. 5. Unifactorial analysis revealed that the percentage of graft survival at one year was 89% and rejection-free survival was 87%. However, the hazard of rejection appeared to increase at or after the time of suture removal. 6. The percentage of recipients in whom CVA was 6/24 or better (able to read normal text with correction) improved from 16% preoperatively to 59% at 3 and 70% at 12 months postoperatively overall. In patients transplanted purely for visual reasons, improvement was 78% and 83% at 3 and 12 months, respectively. 7. Interim results of multifactorial analysis suggest that the risk of graft failure, rejection, and decreased CVA increased in association with the following factors: surgeons who reported fewer than 50 transplants to the study; recipients under 10 years of age; previously failed grafts (the more failed grafts, the greater the risk); grafting for nonvisual reasons; certain diagnoses; and vascularization of the corneal bed prior to transplantation. 8. Astigmatism was investigated in 880 cases at 3 months postoperatively. Preliminary analysis indicated that the risk of severe astigmatism was influenced by suturing technique and large differences between (> 0.25 mm) donor and recipient trephine size. 9. The effects of HLA matching were evaluated in 542 transplants. HLA-A and B matching reduced the risk of rejection during the first 450 days posttransplant, but HLA-DR matching appeared to increase the risk of rejection. 10. A rat model designed to simulate clinical corneal grafting was used to investigate the interaction between immunosuppression and matching. Whereas MHC mismatching could be overcome with topical dexamethasone, non-MHC mismatching appeared resistant.(ABSTRACT TRUNCATED AT 400 WORDS)
Bradley
B A
BA
University of Bristol, Department of Transplantation Sciences, United Kingdom.
Vail
A
A
Gore
S M
SM
Rogers
C A
CA
Armitage
W J
WJ
Nicholls
S M
SM
Easty
D L
DL
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D002648:Child; D002675:Child, Preschool; D003316:Corneal Diseases / Q000601:surgery; D016039:Corneal Transplantation / Q000009:adverse effects / Q000379:methods / Q000706:statistics & numerical data; D005260:Female; D005500:Follow-Up Studies; D006085:Graft Survival; D006648:Histocompatibility; D006801:Humans; D007223:Infant; D015948:Keratoplasty, Penetrating / Q000009:adverse effects / Q000379:methods / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D051381:Rats; D009927:Tissue and Organ Procurement; D016896:Treatment Outcome; D006113:United Kingdom