Pathologic classification of chronic allograft nephropathy: pathogenic andprognostic implications

Background, After transplantation renal allografts frequently develop inter stitial fibrosis and tubular atrophy, and these pathologic changes are the hallmarks of chronic allograft nephropathy (CN). However, the diagnosis of CN has no specific pathogenic implications. In this study we sought to dete rmined whether a subclassification of GN according to vascular pathology co rrelates with posttransplant events, particularly acute rejection, and graf t survival, Methods, A total of 419 patients with moderate to severe CN were subdivided into: (1) transplant arteriopathy (TA, n=233, 56%); (2) arteriolar hyalino sis (AH, n=89, 21%); and (3) no characteristic vascular pathology (IFb, n=9 7, 23%). Results, Patients with AH differed significantly from patients with TA or I Fb in the following parameters: (1) AH was diagnosed later after transplant ation (P=0.001); (2) fewer patients with AH had acute rejection (AR) before the diagnosis of CN (P<0.0001). For example, 44% of AH and 75% of TA had A R before CN; (3) patients with AH also had fewer AR, episodes than the othe r two groups (P<0.0001); finally, (4) graft survival was better in patients with AH than in patients with TA (P=0.01 by chi(2), P=0.001 by Cox). In co ntrast, there were no significant differences between patients with TA and IFb, By multivariate analysis the survival of grafts with CN correlated wit h: (1) serum creatinine at diagnosis (P<0.0001), (2) recipient's weight (P= 0.004); (3) presence of FGS or level of proteinuria (P=0.03); and (4) the o ccurrence of AR after the diagnosis of CN (P<0.0001), Regarding the latter, AR were more common (P=0.007) and more numerous (P=0.005) in patients with TA or IFb than in AH, Conclusions. CN can be classified according to vascular pathology in the ma jority of eases, and this classification correlates with graft survival. Al though some forms of CN are closely associated with the occurrence of An ot hers are not, This study also uncovered several variables that correlate wi th title survival of grafts with CN.