Diagnosis of pancreas rejection

Background: The most common cause of graft failure after technically successful pancreas transplants is rejection. Laboratory parameters for detecting pancreas graft rejection are not consistently reliable and can lead to unnecessary antirejection treatment. Histopathologic evaluation is the gold standard in the differential diagnosis of pancreas graft dysfunction. Four biopsy techniques have been described: cystoscopic transduodenal (CB), percutaneous computed tomography scan-guided (PB, open, and laparoscopic biopsy. Methods: We studied the two most common techniques, CB and PB, in pancreas transplant recipients with presumed rejection. Group 1 comprised 103 attempts at CB in 82 recipients (53 men, 29 women) with bladder-drained (BD) pancreas transplants, at 1 to 80 (median, 14) months after transplant. Group 2 comprised 93 attempts at PB in 68 recipients (41 men, 27 women), at 0.5 o 64 (median, 14) months after transplant. Results: In group 1, of 103 attempts at CB, adequate tissue was obtained in 90 (87%): pancreas alone in 23 (22%), pancreas + duodenum in 35 (34%), duodenum alone in 32 (31%). Of the 58 pancreas biopsies, 23 (40%) showed acute rejection. Of the 67 duodenal biopsies, 16 (24%) showed acute rejection. Complications of CB included machohematuria in 4 recipients (4%) and microhematuria in 32 (31%). We noted no biopsy-related pancreatitis. The mean cost of CB was $2561±246. In group 2, of 93 attempts at PB, adequate tissue (all pancreas) was obtained in 67 (72%); of these, 29 (43%) showed acute rejection. Of 23 inaccessible pancreases, 9 (39%) underwent CB; pancreatic tissue was obtained in four (45%), and results were consistent with rejection in all four. Complications of PB included biopsy-related pancreatitis (serum amylase ≤25%) in five (7%) recipients, macrohematuria in one (1%), and abdominal hemorrhage in two (3%). The mean cost of PB was $1038±78. (1) CB and PB prevented unnecessary antirejection treatment in 44% of our recipients with successful biopsies; (2) CB had a higher success rate for obtaining tissue (including duodenal specimens) and a lower rate of major complications; (3) PB was easier and cheaper, did not require general anesthesia, and was performed as an outpatient procedure. Conclusions: We conclude that PB should become the biopsy technique of choice in recipients with presumed pancreas graft rejection. If PB fails, recipients with bladder-drained pancreas transplants should undergo CB. If CB fails, or in recipients with enteric-drained or duct-injected pancreas transplants, a laparoscopic or open biopsy should be considered.