[354] Decreased Acute Cellular Rejection in Transplanted Heart Biopsies

Y Chi, G Wool, S Fedson, AN Husain. University of Chicago, Chicago, IL

Background: Acute cellular allograft rejection (ACR) is the primary cause of morbidity and mortality in heart transplant patients. The pathology classification was modified in 2004 to collapse 1A, 1B, and 2 into one grade (1R). We reviewed our experience with old and new grading system to evaluate any difference in ACR over time.
Design: From 2002 to 2009, 210 cardiac transplants were performed in our medical center. The endomyocardial biopsies (EMBs) were performed for routine surveillance and graded according to the Working Formulations from International Society for Heart Transplantation in 1990 and 2004. Primary pathologist was the same for all biopsies. The pathological data were entered in a database. In this study, 390 EMBs from 23 cardiac allograft recipients transplanted before 12/31/2002 were compared with 797 EMBs from 57 patients transplanted between August 2006 and March 2009.
Results: As shown in Table 1, the number of EMBs with no cellular rejection increased from 61% to 73% (p<0.001). The number of EMBs with ACR decreased from 39% to 27%, as follows: grade 1A (21.0% to 18.7%, p=0.341), grade 1B (11.8% to 5.1%, p<0.001), grade 2 (3.6% to 1.9%, P=0.073), 3A (1.5% to 0.75%, p=0.204), and 3B (1.3% to 0.5%, p=0.146). However, the number of Quilty lesions has remained the same (Quilty A: 10.8 vs. 10.3%, p=0.799) or increased (Quilty B: 6.9% to 12.5%, p=0.003).

Table 1. Comparison of EMB data

Degree of ACR/Quilty	# of EMBs (2002)	percentage	# of EMBs (2006-2009)	percentage	P value
G0	237	60.8	582	73.0	0.000
G1A	82	21.0	149	18.7	0.341
G1B	46	11.8	41	5.1	0.000
G2	14	3.6	15	1.9	0.073
G3A	6	1.5	6	0.8	0.204
G3B	5	1.3	4	0.5	0.146
G4	0	0	0	0	N/A
Total	390	100	797	100	N/A
QA	42	10.8	82	10.3	0.799
QB	27	6.9	100	12.5	0.003

Conclusions: The better management of cardiac transplant recipients including improved immunosuppressive agents, better psychosocial screening, and improved preservation of hearts may have reduced the incidence of ACR, primarily in grade 1B. The clinical significance of decreased ACR needs longer clinical follow-up. However, it seems that if only the 2004 grading system was used, such difference in ACR would be attributed to confusion with Quilty lesion rather than finding a true difference in ACR.
Category: Cardiovascular

Monday, March 22, 2010 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 42, Monday Morning