Immediate evaluation of endomyocardial biopsies for clinically suspected rejection after heart transplantation.

BACKGROUND Acute rejection may be suspected in heart transplant recipients in the setting of new onset of clinical symptoms or alterations in cardiac function. Immediate diagnosis may be obtained by performing a frozen section on endomyocardial biopsy (EMB) specimens. However, little is known about the indications for, and the diagnostic reliability of, this procedure. METHODS AND RESULTS EMBs with frozen section (n = 98) from 65 of 214 consecutive orthotopic heart transplant recipients were reviewed and divided into early (< or = 45 days; n = 47) and late (> 45 days; n = 51) posttransplant periods. Frozen section diagnoses (means = 1.5 EMB samples) were compared with corresponding permanent section diagnoses (means = 4.4 EMB samples), and clinical indications were analyzed. Comparison of frozen and permanent section interpretation revealed concordant pathological processes-rejection (n = 31) versus no rejection (n = 37) versus ischemic injury (n = 20)-in 88 of 98 (90%) cases. Discordant pathological processes on frozen versus permanent section in 10 of 98 (10%) cases could be attributed to ischemic injury (n = 5), sampling (n = 4), and infection (n = 1). In the 92 cases with defined clinical indications, the indication and number of EMBs positive for rejection early and late after transplantation were arrhythmia: 2 of 12 early, 4 of 10 late; congestive heart failure: 1 of 2 early, 5 of 12 late; fever: 0 of 2 early, 1 of 4 late; echo abnormality: 0 of 5 early, 0 of 1 late; syncope: 1 of 5 early, 0 of 1 late; hypotension: 1 of 3 early, 1 of 2 late; noncompliance: 0 of 0 early, 4 of 5 late; more than one of the above: 3 of 7 early, 2 of 5 late; other: 1 of 7 early, 1 of 9 late; total: 9 of 43 early, 18 of 49 late. CONCLUSIONS Frozen section on EMB specimens accurately reflected the permanent section diagnosis in 90% of cases. No specific clinical indication predicted EMB rejection positivity with high sensitivity in either the early or late posttransplant periods.