Dialysis modality and the risk of allograft thrombosis in adult renal transplant recipients

Background. Renal vascular thrombosis (RVT) is a rare but catastrophic comp lication of renal transplantation. Although a plethora of risk factors has been identified, a large proportion of cases of RVT is unexplained. Uremic coagulopathy and dialysis modality may predispose to RVT. We investigated t he impact of the pretransplant dialysis modality on the risk of RVT in adul t renal transplant recipients. Methods. Renal transplant recipients (age 18 years or more) who were enroll ed in the national registry between 1990 and 1996 (N = 84,513) were evaluat ed for RVT occurring within 30 days of transplantation. Each case was match ed with two controls from the same transplant center and with the year of t ransplantation. The association between RVT and 18 factors was studied with multivariate conditional logistic regression. Results. Forty-nine percent of all cases of RVT (365 out of 743) occurred i n repeat transplant recipients with an adjusted odds ratio (OR) of 5.72 com pared with first transplants (P < 0.001). There were a significantly higher odds of RVT in peritoneal dialysis (PD)-compared with hemodialysis (HD)-tr eated patients (OR = 1.87, P = 0.001). Change in dialysis modality was an i ndependent predictor of RVT: switching from IID to PD (OR = 3.59, P < 0.001 ) and from PD to HD (OR = 1.62, P = 0.047). Compared with primary transplan t recipients on HD (OR = 1.00), the highest odds of RVT were in repeat tran splant recipients treated with PD (OR = 12.95, P < 0.001) and HD (OR = 4.50 , P < 0.001). Other independent predictors of RVT were preemptive transplan tation, relatively young and old donor age, diabetes mellitus and systemic lupus erythematosus as causes of end-stage renal disease, recipient gender, and lower panel reactive antibody levels (PRAs). Conclusions. The strongest risk factors for RVT were retransplantation and prior PD treatment. Prevention of RVT with perioperative anticoagulation sh ould be studied in patients who have a constellation of the identified risk factors.