EFFECT OF ADOPTING A NEW HISTOLOGICAL GRADING SYSTEM OF ACUTE REJECTION AFTER HEART-TRANSPLANTATION

Background-Treatment policy of acute rejection after heart transplanta tion has been changed after adopting the ISHLT endomyocardial biopsy g rading system in 1991. Objective-To determine the effect of this polic y change on clinical outcome after transplantation. Methods-The outcom e of 147 patients who had a transplant before (early group, median fol low up 96 months) and 114 patients who had a transplant after (late gr oup, median follow up 41 months) the introduction of the ISHLT biopsy grading system was studied retrospectively. Initially ''moderate rejec tion'' according to Billingham's conventional criteria was treated. Fr om January 1991 grade 3A and higher was considered to require intensif ication of immunosuppression. Results-There were some differences betw een the two groups: recipients (50 v 44 years) as well as donors (28 v 24 years) were older in the ''late group'' and more patients of this group received early anti-T cell prophylaxis (92% v 56%). Despite more extensive use of early prophylaxis more rejection episodes were diagn osed (2.4 v 1.4) and considerably more courses of rejection treatment were instituted in the late compared with the early group (3.2 v 1.5). There were no deaths because of rejection in the late group, however, more infections occurred within the first year (mean 1.8 v 1.4) and m ore non-skin malignancies within the first 41 months were diagnosed (8 of 57 v 6 of 147, 95% CIs of difference includes 0). The incidence of graft vascular disease in the late group has been comparable to the e arly group until now. Conclusion-The interpretation of the ISHLT gradi ng system resulted in lowering of the threshold for the diagnosis of r ejection thereby increasing the number of rejections and subsequently the immune suppressive load and its complications.