Cardiac Rejection Grading

General: The ISHLT (International Society for Heart Lung Transplantation) Grading system established the most widely used grading system in 1990, though several proposals have attempted to modify/simplify the system, largely based around clinical treatment cutoffs. In addition to the grade, reports should address adequacy of the biopsy, evidence of infection & organism if identified (such as CMV), and changes perhaps not considered related to transplant.

Proposed in 1998 as an update to the ISHLT guidelines.

	1990 System		Proposed
No rejection	0	Biopsy specimens with very sparse lymphoid infiltrates should be included in this grade	Grade 0
"Mild" rejection	1A	Focal perivascular or interstitial infiltrates. The mild intensity and lack of myocyte damage distinguish this from higher grades.	Grade 1
	1B	Diffuse but sparse infiltrates. As with 1A, there must be no myocyte damage.
"Focal" moderate rejection	2	One focus only with aggressive infiltration and/or focal myocyte damage. The choice of a single focus as the cut off point from higher grades is arbitrary. In practice, with the amount of tissue usually submitted, one is unlikely to be faced with the problem of biopsy fragments with only two foci.

USUAL TREATMENT THRESHOLD

"Low" moderate rejection	3A	Multifocal aggressive infiltrates and/or myocyte damage. The multiple foci may be present in only one fragment or scattered throughout several fragments.	Grade 3A
	3B	Diffuse inflammatory process. The intensity of the lymphoid infiltrate varies considerably; it may be little more than 1B. The important feature distinguishing this grade is the presence of myocyte damage. This damage must be present in at least two fragments but some degree of infiltration is present in most fragments.	Grade 3B
"Severe acute" rejection	4	A diffuse and polymorphous infiltrate with or without oedema, haemorrhage, and vasculitis. The infiltrate is more intense and more widespread than 3B, and myocyte damage is conspicuous. There are often neutrophils and/or haemorrhage, although neither is essential for classification as this grade.	Grade 4

(Heart 1998;79:423)