The histopathologic consequences of endomyocardial biopsy in normal (nontransplanted) baboon hearts have been investigated. Organization of the thrombus, necrosis of myocytes adjacent to the biopsy site, and the presence of mononuclear cells (including T-lymphocytes) surrounding the biopsy site occur following biopsy and, should a subsequent biopsy be taken from this area, present a potential for confusion with the appearances associated with acute or resolving cardiac rejection. We have encountered this problem in our clinical transplant program. Awareness of the effects of biopsy procedure itself should lead to caution in the interpretation of the histopathologic features and may avoid unnecessary extra immunosuppression in patients early after transplantation.
