Arteriolar vasculitis on endomyocardial biopsy: a histologic predictor of poor outcome in cyclosporine-treated heart transplant recipients.

The histologic pattern of severe, potentially lethal cardiac rejection in transplant recipients who are treated with cyclosporine may be difficult to distinguish from mild or moderate rejection. The purpose of this study was to determine whether specific histologic abnormalities seen on endomyocardial biopsy could identify which histologic patterns of rejection are associated with progression to graft dysfunction or graft failure. We performed a blinded, retrospective analysis of endomyocardial biopsies from our initial 19 transplant recipients. Group 1 was composed of five patients who developed graft failure or dysfunction after transplantation. Group 2 was composed of the remaining 14 patients with normal hemodynamics and function at heart catheterization 1 year after transplantation. Seventeen histologic parameters were semiquantitatively graded, and comparisons between the two groups were made with the Student's t test. Of the 17 parameters, only arteriolar vasculitis was significantly increased in group 1 versus group 2 biopsies (p = 0.002). Arteriolar vasculitis was identified in four of five patients in group 1 and was unique to group 1. Of 53 group 1 biopsies, eight patients had foci of arteriolar vasculitis and were seen up to 88 days before graft failure. Therefore the finding of arteriolar vasculitis on endomyocardial biopsy may identify high risk rejection episodes in transplant recipients who are treated with cyclosporine.