Indications and epidemiological profile of patients submitted

Purpose: To define the epidemiological aspects of the patients submitted to keratoplasty in the state of Santa Catarina, Brazil and the main indications for this procedure. Methods: We conducted an observational, descriptive and retrospective study with the data of 1161 patients submitted to cornea transplantation from january 2008 to december 2010, at the Transplantation Center of Santa Catarina. The analyzed data were: age, gender, origin, transplant date, indication and transplanted eye. Results: The mean age was 45.51 years and men were more commonly operated. Keratoconus was the most common disease (36.09%), followed by graft failure (15.89%), leukoma (11.92%), bullous keratopathy (11.06%), dystrophy (7.77%), ulcer (5.36%), corneal perforation (5.27%), descemetocel (4.66%), herpetic keratitis (1.12%) and corneal ectasia (0.86%). The region with the greater number of cases was the Great Florianopolis (23.75%), with keratoconus as the main indication (30.91%). Leukoma and perforation were the mainly indication in patients under 10 years old, keratoconus in patients between 11 and 50 years old, graft failure between 51 and 60 years old and bullous keratopathy in patients under 61 years old. Conclusion:Keratoconus is the main indication for keratoplasty in our state, with the mean age of 31 years. Most of the patients were men and from the Great Florianopolis.


F
or years, physicians attempted to restore damaged corneas without success.It was only in the mid-19 th century that Powers (1878) and other surgeons conducted studies that elucidated the physiology of corneal tissue, which provided Eduard Zirm the knowledge and techniques necessary to perform the first successful penetrating keratoplasty in 1905 (1)(2)(3)(4) .
Corneal transplantation can be classified according to: biological type (autograft, where the donated cornea and the host eye are from the same individual; allograft, where the cornea is transplanted between individuals of the same species; and xenograft, where the donated cornea and the host eye are from individuals of different species); surgical technique (lamellar, where only a part of the corneal thickness is replaced; and penetrating, where the entire tissue is replaced); and transplanted portion (partial, where part of the diameter is transplanted; and total, where the entire diameter is transplanted) (5,6) .
The cornea is currently the most frequently transplanted tissue in the United States, Europe (7) , and, since 1998, Brazil (8,9) .Transplantation is done for optical, reconstructive, therapeutic, or cosmetic reasons (5,6) .The increasing number of transplants is explained by improved organisation of eye banks, better selection of donated tissue, and advances in pharmacology, immunology, and eye microsurgery, allowing transplants in situations previously considered inoperable (6,10) .In Brazil, the National Transplant System (Sistema Nacional de Transplantes [SNT]), working through each state's Organ Notification, Collection and Distribution Unit (CNCDO), coordinates the Human Eye Tissue Banks, which are responsible for the logistics and storage of collected corneas and the registration of donors and recipients (11) .

METHODS
This was an observational and descriptive study on patients undergoing keratoplasty between January 2008 and December 2010.Data were collected retrospectively from the records of Santa Catarina's CNCDO (CNCDO-SC) using SNT version 5.0.A total of 1,161 charts were evaluated, and three were excluded because they had incomplete data.The following variables were collected: age, sex, origin, transplant date, indication, and operated eye.The type of keratoplasty was not considered as a variable, since it was not listed in the database.
The patients' cities of origin were grouped into regions according to the classification of the Brazilian Institute of Geography and Statistics (IBGE): Greater Florianópolis, North, West, Mountain Region, South, and Itajaí Valley (25) .Patients from cities outside Santa Catarina were included in the Other States group.
Microsoft Excel™ 2010 was used to organise and analyse the data.Data were expressed as means, standard deviations (SD), and percentages.
This study was registered on the Plataforma Brasil register of the Brazilian Ministry of Health under Protocol CAAE 01062812.3.0000.0121.

RESULTS
Of the 1,158 patients subjected to transplantation during the study period, 652 were male (56.30%) and 506 were female (43.70%).Patient age ranged from 0 to 93 years; mean age was 45.51 (SD 19.75).In total, 626 (54.05%) transplants were performed in the right eye and 532 (45.95%) in the left eye.

DISCUSSION
The present study retrospectively and descriptively evaluated 1,158 records of corneal transplants performed between January 2008 and December 2010.Data were obtained from CNCDO-SC using SNT version 5.0.A nearly linear annual increase in the number of transplants was observed, as previously described by Maeno et al. (17) , probably due to the increasing number of donors, better coordination between eye banks and CNCDO-SC, and improvements in surgical technique (16) .
Keratoconus was the main indication for corneal transplantation (36.09%), similar to a study conducted in the city of Florianópolis where 28.7% of transplants had this indication (5) .Keratoconus is a bilateral corneal ectasia typically affecting older teens and young adults (26) , which corresponds to the mean age for the disease found in our study (31 ± 10.73 years) and also in Garcia et al. (27.2 years) (5) , Al-Yousuf et al. (32.5 ± 11.70 years) (7) , Maeno et al. (34.43 years) (17) , and Edwards et al. (31.8 years) (21) .
Graft failure (and consequent retransplantation) was more frequent in our study (22.18% of cases in Florianópolis) than in Garcia et al. (8.3%) (5) ; this finding partially contradicts the analysis by Kanavi et al. (22) , according to whom the number of retransplantations will tend to decrease over time.Dobbins et al. (16) state that improvements in technology and surgical skills lead to an increase in the number of transplants, resulting in more patients with the potential to develop graft failure.Moreover, with the increased incidence of retransplantation this group will continue to grow, since the chances of graft survival decrease after each successive retransplantation (18) .This might explain why graft failure was the second leading indication (15.89%) in our population.
Leukoma, which was the third leading indication in our sample (11.92%), had a variable incidence in previous studies (8,9,12- 15,22,23) .Because leukoma is a sign rather than a diagnosis, it can be difficult to determine its aetiology and thus its actual incidence, resulting in errors in completing the medical record (15) .Bullous keratopathy, the main indication in some studies (15,16,18,19) , was the fourth leading indication in our study (11.06%), with a high frequency in patients older than 60 years (31.13% of transplants, mean age 68 ± 13.74 years).This is because bullous keratopathy is the main complication of phacoemulsification and intraocular implants, which are increasingly popular procedures since the 1980s (3,4) .However, considering that in the study by Garcia et al. (5) bullous keratopathy was the third most frequent indication in Florianopólis, it can be assumed that improvements in the surgical technique, as well as intraocular lenses of better quality and greater use of viscoelastic substances to protect the corneal endothelium, have reduced the incidence of this postoperative complication (13,16,24) .
It is important to emphasise that the data classification used by SNT is based on the diagnoses made by the professionals involved in transplantation, rather than following a rigorous protocol.This creates difficulties in grouping the diagnoses that led to the indication of keratoplasty.
The distribution of indications by age is shown in Table 2.For patients younger than 10 years, leukoma and corneal perforation shared first place (27.27% each), a finding similar to Pimentel et al. (27) .In our study, keratoconus was the leading indication for transplantation in patients aged 11-50 years, in agreement with a study conducted by Flores et al. (3) in 2007 at the University of Campinas.Both studies also agreed regarding patients aged 71-80 years, where bullous keratoplasty was the main indication, mainly because of the high number of phacoemulsification procedures performed in this age group.However, differences were observed among the various studies for other age groups.
The time constraints and the findings of this study are an incentive to conduct further research in order to assess whether the observed trends are maintained.

CONCLUSION
The present study retrospectively and descriptively evaluated 1,158 records of corneal transplants performed between January 2008 and December 2010.Data

Figure 2 :
Figure 2: Distribution of keratoconus as main indication for keratoplasty between 2008 and 2010, according to the patient's region of origin; CNCDO-SC.