Histologic grading of cardiac allograft rejection: a quantitative approach.

At the Texas Heart Institute, cardiac allograft rejection is evaluated by a quantitative, or numerical, scale ranging from 0 to 10. This scale provides objectivity as to the degree of cardiac allograft rejection and thus enhances communication between pathologists, surgeons, cardiologists, nurses and patients. The system is simple, reproducible with minimal interobserver variability, and is easily learned. Each time a grade of rejection changes for a patient, alterations are required in the therapeutic approach, especially in the "moderate" range (grades 4-8). By plotting the numerical value and date of a patient's previous endomyocardial biopsies on the 0-10 scale, accurate determinations may be made of (1) the degree of cardiac allograft rejection, (2) the direction of change (resolving or progressing), and (3) the speed of change. All three parameters are important in determining the appropriate immunosuppressive regimen and biopsy interval for each patient.