Elevated blood pressure predicts the risk of acute rejection in renal allograft recipients

Background. Acute rejection (AR) is a strong predictor of renal allograft s urvival. Recent advances in immunosuppression have reduced considerably the incidence of AR. Still, approximately 25% of patients have AR early post-t ransplant, and the factors that predispose to AR have not been fully clarif ied. Methods. The study includes 1641 adults, recipients of first cadaveric (CAD , N = 1195) or living related renal grafts (LRD, N = 446), transplanted in one institution. The variables associated with the occurrence of AR during the first year posttransplant were identified. Results. By univariate analyses, AR was associated with the following varia bles: younger (P < 0.001); heavier (P = 0.003); and African American recipi ents (P = 0.002); CAD transplants (P = 0.001); higher number of HLA mismatc hes (P = 0.001); delayed graft function (DGF, P = 0.001); higher levels of serum creatinine post-transplant (P = 0.003); and higher levels of systolic and/or diastolic blood pressure (BP) post-transplant (P < 0.001). Higher B P levels were also associated with earlier AR episodes (P < 0.0001). By mul tivariable analysis AR was significantly associated with recipient age, num ber of HLA mismatches, DGF, pre-PRA and systolic BP. Analysis of BP measure d weekly post-transplant indicated that elevated BP levels, even three week s prior to the AR episode, were significantly associated with AR. For every level of BP, the use of BP medications was associated with a lower inciden ce of AR (P < 0.0001). Furthermore, the use of calcium channel blockers was also associated with lower incidence of AR (P = 0.001). Of note, 81% of re cipients whose BP increased after the transplant had AR. In contrast, 22% o f patients whose BP declined post-transplant had AR. Conclusions. Elevated BP levels post-transplant identify patients at high r isk of AR independently of graft function. Treatment of BP and reduction of BP levels appears to be associated with a decreased risk of AR. We hypothe size that high BP may be an indicator of a particular type of allograft dam age, perhaps ischemic, that may predispose to AR.