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Volume: 12 Issue: 6 December 2014

FULL TEXT

ARTICLE
Evaluation of the Effects of Recipient/Donor Gender on Early/Late Postoperative Renal Graft Functions by Renal Scintigraphy

Objectives: We discuss the effects of recipient/donor gender on renal allograft functions using scinti-graphic parameters obtained 3 days after renal transplant and 1 year after transplant.

Materials and Methods: This retrospective study included 76 renal allograft recipients (group one, 38 males; group two, 38 females). Patients underwent scintigraphic imaging with Tc-99m DTPA on postoperative day 3 and 1 year after transplant. We used the Hilson perfusion index, maximum renal activity/background activity, ratio of renal activity at 20 minutes to renal activity at 3 minutes, time-to-peak activity, and glomerular filtration rate to measure quantitative parameters.

Results: On postoperative day 3, the Hilson perfusion index, maximum renal activity/background activity, the ratio of renal activity at 20 minutes to renal activity at 3 minutes, time-to-peak activity, and glomerular filtration rate values for male/female recipients were similar (P = .65, P = .77, P = .38, P = .10, P = .99). The gender of donors was compared with the above-mentioned scintigraphic parameters of the recipients, and no statistically significant differences were found (P = .24, P = .25, P = .44, P = .29, P = .13). At 1-year follow-up, values obtained from group 1 and group 2 recipients were similar. After 1 year, chronic rejection developed in 15.7% of group 1 recipients and in 10.5% of group 2 recipients; acute rejection developed in 21% of group 1 recipients and in 23.6% of group 2 recipients. There were no statistically significant differences between the occurrence of acute rejection and the gender of recipients or donors (P = 1.00, P = .45).

Conclusions: We observed no statistically significant differences between renal graft functions and gender of the recipients/donors during the early/late posttransplant period.


Key words : Kidney transplant, Postoperative period, Gender identity, Radionuclide imaging

Introduction

Renal transplant is a favored treatment for chronic renal failure. Renal allograft functions in the early postoperative period and long-term graft survival are affected by several factors. These factors include rejection, living/deceased-donor transplants, cold ischemia time, and properties of recipients/donors such as age, gender, and race.1 Early stage allograft functions affect graft survival, and several studies demonstrate that delayed graft functions during the early postoperative period affect transplant outcomes.2,3 The occurrence of delayed graft functions is increased by the presence of certain risk factors. Transplant from a female donor to a male recipient is one of these factors.4 Studies indicate that male recipient gender is a risk factor for impaired, but not delayed, early graft function.5 Therefore, imaging of early functions of renal allograft and monitoring long-term outcomes are important. Renal transplant scintigraphy, which can be used to monitor early/long-term functions of a renal allograft and to perform diagnoses, has been used for this purpose. Here, we discuss the effects of donor/recipient gender/age on renal allograft functions using scintigraphic perfusion and parenchymal phase quantitative parameters obtained 3 days after transplant and 1 year after transplant.

Materials and Methods

Seventy-six patients between 1995 and 2004 underwent a renal transplant at Başkent University Faculty of Medicine in Ankara, Turkey. Their medical records were retrospectively reviewed. Subjects were divided into 2 groups: group 1 (38 male; mean age, 32.6 ± 12.4 y; age range, 13-56 y) and group 2 (38 female; mean age, 26.34 ± 10.4 y; age range, 10-46 y). Kidneys were recovered from living donors in 23 patients for each group.

Mean cold ischemia time of deceased donors in group 1 and in group 2 were evaluated and compared. Of both living and deceased donors, 34 were men (44.7%) and 42 were women (55.2%). The mean age of donors in group 1 was 41.25 ± 13.3 years (age range, 11-75 y), and the mean age of donors in group 2 was 38.75 ± 8.2 years (age range, 2-59 y). In group one, 19 donors were male and 19 were female; in group two, 15 donors were male and 23 were female (Table 1). Of recipients, 10 were older than 50 years (all men), and 66 were younger than 50 years (all women). Of donors, 15 were older than 50 years (7 men, 8 women), and 61 were younger than 50 years (27 men, 34 women).

Patients underwent scintigraphic imaging with Tc-99m diethylene triamine pentaacetic acid (DTPA) at postoperative day 3 and 1 year after transplant. The diagnosis of acute or chronic rejection was made by core-needle renal graft biopsy in patients with the following abnormal scintigraphic values: Hilson perfusion index (HPI), maximum renal activity/background activity (MA/B), ratio of renal activity at 20 minutes to renal activity at 3 minutes (R20/3), time-to-peak activity (Tmax), and glomerular filtration rate (GFR). Mean weights of recipients/donors were compared. The differences between creatinine levels of the male/female recipients 1 year after transplant were statistically evaluated. Patient follow-up was 1 year. The study was approved by the Ethical Review Committee of the institute. All protocols conformed with the ethical guidelines of the 1975 Helsinki Declaration.

Immunosuppressive protocol
All recipients were given standard immuno-suppressive protocol consisting of cyclosporine (tacrolimus has replaced cyclosporine since 2000), steroids, and azathioprine (mycophenolate mofetil has replaced azathioprine since 1999).

Scintigraphic protocol
All patients underwent scintigraphic imaging with Tc-99m DTPA 3 days after renal transplant and 1 year after renal transplant. Before imaging studies, we required patients to be hydrated and to empty their bladder. We placed them underneath the camera in a supine position. After a bolus injection of 259 MBq/70 kg Tc-99m DTPA (Mallinckrodt, Holland), we obtained anterior dynamic images with dual-head gamma camera (Siemens, E.Cam, Erlangen, Germany) with a low-energy, all-purpose collimator recorded on a 64 × 64 matrix at 1 second/frame for 60 seconds (perfusion images) and 20 seconds/frame for 20 minutes (function images). Perfusion time-activity curves were derived from regions of interest (ROI) over the renal graft and the contralateral iliac artery. We derived functional parameters from ROI over the graft and background ROI inferolateral to the graft. The functional parameters were Tmax, MA/B, and R20/3. We used perfusion time-activity curves to calculate HPI from the ratio of the areas under the arterial and renal curves in which values less than 96% were considered normal. We calculated GFRs using camera-based methods (Gates methods), and GFRs less than 45 mL/min were considered pathologic.

Statistical analyses
Statistical analyses were performed with SPSS software (SPSS: An IBM Company, version 16.0, IBM Corporation, Armonk, NY, USA). The results were analyzed using the independent sample t test and the chi-square test for independence. Values for P < .05 were considered statistically significant.

Results

On renal scintigraphy performed 3 days after renal transplant, HPI, MA/B, R20/3, Tmax, and GFR values obtained from male/female recipients were similar (P = .65, P = .77, P = .38, P = .10, P = .99; P = NS for all parameters tested). No statistically significant between-group differences existed with regard to the parameters tested. The gender of the donors was compared by all the scintigraphic parameters of the recipients, and no statistically significant differences were found (P = .24, P = .25, P = .44, P = .29, P = .13; P = NS for all parameters tested). Table 2 shows the average values of the parameters for both groups 3 days after surgery. (Figure 1 shows an example of function phase image within normal ranges 3 days after renal transplant in a man, and Figure 2 shows the same example in a woman.)

Regarding deceased donors, mean cold ischemia time was 16.38 ± 3.22 hours in group 1, and it was 16.72 ± 2.8 hours in group 2. Cold ischemia time did not differ among all patients regarding allografts from deceased donors (P = .97).

The difference between the mean ages of male and female recipients was statistically significant (P = .02). There was no statistically significant difference between the mean ages of donors for the group 1 and group 2 (P =.96).

The mean weights of the recipients and donors were 64.36 ± 3.53 kg and 65 ± 2.83 kg (P = .78). The mean weights of the recipients (for group 1 and group 2) were 64.11 ± 2 kg and 63.8 ± 1.81 kg. The mean weights of the donors (for group 1 and group 2) were 66.4 ± 3.3 kg and 64.25 ± 2.5 kg (P = .80, P = .75).

No statistically significant difference existed regarding creatinine levels 1 year after transplant between group 1 or group 2 recipients (129.06 μmol/L [1.46 ± 0.52 mg/dL] and 121.10 μmol/L 1.37 ± 0.5 mg/dL]) (P = .68).

A biopsy specimen from a woman with an abnormal renal transplant scintigraphy parameters 7 days after transplant revealed acute tubular necrosis; however, 1 year after transplant, her graft functions had returned to normal. The diagnosis of acute rejection was made by biopsy in 3 female recipients and in 2 male recipients 7 days after surgery. The scintigraphic parameters of these patients were abnormal 3 days after transplant; however, they did not cause a statistically significant difference between group 1 and 2. Two patients from group 1 with functioning grafts died 2 months after surgery.

At 1-year follow-up, HPI, MA/B, R20/3, Tmax, and GFR values obtained from group 1 and group 2 recipients were similar (P = .65, P = .69, P = .37, P = .11, P = .99) (Table 3). At 1-year follow-up, using HPI, MA/B, R20/3, Tmax, GFR values and biopsy results, the disease was diagnosed as chronic rejection in 15.7% of the group 1 recipients (n=6) and in 10.5% of the group 2 recipients (n=4); whereas, the disease was diagnosed as acute rejection in 21% of the group 1 recipients (n=8) and in 23.6% of the group 2 recipients (n=9).

Neither recipient gender, nor donor gender, affected the occurrence of episodes of graft rejection (P = 1.00, P = .45). All acute rejection episodes were treated with steroids.

Discussion

Early/long-term outcomes of renal transplant are affected by several factors. These factors include recipient/donor age, gender, human leukocyte antigen types, and acute rejection episodes. It has been reported that age/gender of recipients/donors should be reciprocally compatible to achieve better outcomes in organ transplants.6,7 No difference between other variables—such as the duration of dialysis, cold ischemia time, cause of renal failure, HLA types, episodes of acute rejection, and research on the effects of age, gender, body weight, height, and body surface area of recipients/donors on early graft functions—has been reported.

Although male recipient/donor groups were taller/heavier than were female groups, no significant difference for graft weight was reported.8 Another study has reported that gender differences in serum creatinine levels and in creatinine excretion of donors are associated with differences in recipient metabolic need.9 In living donors older than 65 years, and in recipients younger than 50 years, HLA-DR compatibility and female donors are risk factors for early acute rejection.10

In the current study, the mean ages of patients in groups 1 and 2 were 32.6 ± 12.4 and 26.34 ± 10.4 years. The difference regarding mean ages between male/female recipients was statistically significant (P = .02). However, owing to the small age difference between our male/female patients, we assumed that this difference did not mask the real effect of gender.

In a study regarding the effect of donor gender on graft survival, survival was lower in renal transplants for male recipients of kidneys of female donors compared with female recipients of kidneys of male donors, and this study showed that an increased risk of graft failure for kidneys from younger (16-45 y) female donors.11 In our study, however, there were no statistically significant differences between the occurrence of an acute/chronic rejection and the gender of recipients/donors.

Our study has limitations. The scintigraphic parameters of our patients regarding the threshold age of 50 years were not statistically compared in recipients/donors because the numbers of recipients/donors aged older than 50 years (n = 10, n = 15) were too small when compared with the numbers of recipients/donors aged younger than 50 years (n = 66, n = 61). Also, recipient age and creatinine levels were not statistically compared because the numbers of the recipients aged older than 50 years (n = 10) were too small when compared with the numbers of recipients aged younger than 50 years (n = 66). Despite these limitations, we believe that our study will contribute to the evaluation process of renal allograft donors/recipients because transplant physicians will need to consider the optimal management and re-evaluation of wait list patients during the waiting period.12 We believe that future radionuclide imaging studies with larger groups will contribute to the growing data, which benefit renal transplant patients and increase outcomes.

In conclusion, using scintigraphic perfusion and parenchymal phase quantitative parameters, we observed no statistically significant differences between renal graft functions, regarding recipient/donor gender during the early/late post-transplant period. We consider renal transplant to be an effective therapy for end-stage renal failure patients in both genders.


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Volume : 12
Issue : 6
Pages : 510 - 514
DOI : 10.6002/ect.2013.0275


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From the 1Department of Nuclear Medicine and 4Internal Medicine, Mersin State Hospital, Mersin; and the Departments of 2Nuclear Medicine and 3General Surgery, Başkent University Faculty of Medicine, Ankara, Turkey
Acknowledgements: We appreciate the contribution of Dr. Sevim Turanlı for her help in the statistical analyses. We have no conflicts of interest to disclose, and there was no funding for this study.
Corresponding author: Sevin Ayaz, MD, Nuclear Medicine Specialist, Merkez Mah., 1.Plaj Sokak, No:10, Erdemli, Mersin, Turkey
Phone: +90 324 336 3881 (office), +90 537 7639443 (mobile)
Fax: +90 324 336 0256
E-mail: sevinayaz@yahoo.com