Clinical implications of the diagnosis of renal allograft infarction by percutaneous biopsy

Background. Herein we investigated the relationships between acute rejection (AR), infection, and renal allograft infarcts, particularly those infarcts that occur beyond the immediate posttransplant period and that affect functioning grafts. Methods. Infarcts (n=59) were classified as: (1) early (EI; <2 months after transplant; n=32); or (2) late (LI; >2 months; n=27). Controls included patients with severe AR but without infarction (n=84). Results. There were not significant differences in donor or recipient characteristics between infarcts and controls. At diagnosis, patients with infarcts were more likely to be infected (30%) than controls (14%, P=0.01); 15% of infarcts and 1% of controls had disseminated cytomegalovirus (P=0.04). Infarct and AR coexisted in the biopsy specimens of 66% of patients with EI and 62% of patients with LI, but the AR severity ranged from borderline to severe. Furthermore, 30% of patients with EI/LI had a history of severe AR. Graft survival was 47% in patients with EI, 22% in patients with LI (NS), and 71% in controls (P<0.0001, chi-square and Cox regression). Correlates of better graft survival in infarcts included: older recipient (P=0.03); smaller area of infarction in the biopsy specimen (P=0.04); and use of anti-AR therapy (P=0.03). Therapy was effective in patients with EI (treated, 71% survival; untreated, 29%, P=0.02) but not in patients with LI (25% vs. 23%). Conclusions. Allograft infarcts are associated with AR in 64% of patients, but the AR may be mild. Infarcts are associated with infections. Graft survival is worse in patients with infarcts than in patients with severe AR, consequently these two pathologic diagnoses should not be considered as a single entity.