Cholesterol embolization in renal allografts

Renal cholesterol embolization (RCE) in native kidneys has a dismal outcome and frequently leads to irreversible renal failure. RCE may rarely occur in renal allografts as well, particularly if the recipient or the donor has prominent atherosclerosis. The natural history of RCE in renal transplants is unknown. We have reviewed the surgical pathology files of The Johns Hopkins Hospital in the 14-year period between 1984 and early 1999 and found 7 RCE cases among 1500 renal transplant biopsies (0.47%). One of the seven cases had three biopsies showing cholesterol emboli, the first of which was a postreperfusion (immediate posttransplant) biopsy. The probable source of the cholesterol emboli was the recipient in six cases and the donor in one case. Five donors were cadaveric and two were living donors. Six biopsies were taken within the first 4 months posttransplant (four were postreperfusion biopsies). One recent patient had the inciting event of arteriography and stent placement 2 years posttransplant and is currently doing well. One kidney failed due to posttransplant lymphoproliferative disorder (PTLD), another kidney failed with complicating opportunistic infections, and the other five were functioning 2 to 6 years posttransplant. A literature review revealed additional 14 RCE cases in renal transplants. Combining our cases with those in the literature (21 cases), reveals that the origin of the RCE was probably the recipient in 11 cases (seven cadaveric, two living-related, and two unknown), and the donor in 10 cases (eight cadaveric and two unknown). Graft failure occurred in two of the 11 cases, where RCE was of probable recipient origin. Seven of the 10 kidneys, where the RCE was probably of donor origin, failed due to allograft dysfunction; one of them also developed superimposed rejection and cytomegalovirus infection. We conclude that if RCE is originating in the recipient, graft survival is usually good. In contrast, if RCE is of donor origin, graft dysfunction and subsequent graft loss are common. The reason for this difference may be the more extensive RCE developing in an atherosclerotic cadaveric donor during organ procurement or severe trauma leading to death.