REVISION OF THE 1990 WORKING FORMULATION FOR CARDIAC ALLOGRAFT-REJECTION - THE SHEFFIELD EXPERIENCE

Objective-To audit the 1990 International Society for Heart and Lung T ransplantation cardiac rejection criteria and to evaluate the impact o n classification and clinical outcomes of a modification in which grad e 2 is abolished and grades 1A and 1B are amalgamated into a single '' grade 1.'' Methods-1652 heart biopsies were reviewed over a four year period. The initial 1348 biopsies (group 1), using the original 1990 c riteria, were analysed in terms of diagnostic grade and compared with the 304 biopsies analysed with the modified scheme (group 2). Differen ces in grading with the 1990 scheme were compared between two groups ( 1.1 and 1.2) reflecting early and late experience with grading. Subseq uently all the grade 2 and grade 1B biopsies were rescored in terms of the modified scheme. Clinical results in terms of actuarial patient s urvival at one year and freedom from 3A rejection were similarly audit ed. Results-The relative ratios of potentially significant rejection ( grade 3A, 3B, 4) remained constant over the entire study ingroups 1.1, 1.2, and 2. A 50% reduction in grade 2 biopsy reporting was noted com paring early and late parts of group 1. At subsequent review of the gr oup 1 grade 2 biopsies, 97% could be reassigned to grades 0 or 1 in th e modified scheme, with the majority of these diagnoses reflecting Qui lty effect/biopsy site reactions. Two cases (3%) of the 77 grade 2 bio psies were regraded as grade 3A rejection, with both occurring within three months of transplantation. None of the grade 1B biopsies had hig h grade cardiac rejection on review, most of these biopsies similarly showing pronounced Quilty effect and biopsy site reactions. Actuarial survival at one year rose hom 86% to 90% during the study, with freedo m from 3A rejection remaining unchanged at 80%. Conclusions-The origin al working formulation produces consistent grading except at grade 2, which is judged to be a misnomer resulting from om Quilty effect and o ther non-rejection phenomena. While acceptable standardisation can be achieved with the 1990 scheme, the modified scheme has advantages in t hat it appears to encourage clear discrimination between significant a nd non-significant cardiac rejection. Overall, elimination of grade 2 did not produce an increase in higher grades of cardiac rejection, and thus the value of this diagnostic grade is questioned.