Acute rejection after heart transplantation: noninvasive echocardiographic evaluation.

OBJECTIVES: The purpose of this study was to assess the reliability of echocardiography in the noninvasive diagnosis of acute rejection in heart transplant recipients.
BACKGROUND: Although echocardiographic results seem to correlate well with allograft rejection, published data are limited and contradictory.
METHODS: In 130 transplant recipients, 1,400 serial echocardiograms were recorded within 24 h of endomyocardial biopsy. Increased wall thickness, myocardial echogenicity, pericardial effusion, shorter pressure half-time, isovolumetric relaxation time and a decrease in left ventricular ejection fraction were considered markers of rejection.
RESULTS: The distribution of echocardiographic markers revealed highly significant differences between bioptically graded moderate, mild and no rejection and between untreated and treated rejection episodes (both chi-square test, p < 0.0001). Specificity was 98.6% for two markers, but sensitivity was good (80%) for only moderate rejection because of the large number of false negatives in untreated patients with mild rejection. In untreated patients, there was a highly significant difference in the number of echocardiographic criteria between a benign and nonbenign outcome (chi-square test, p < 0.0001). In treated patients, the significant difference in the variation in echocardiographic criteria between favorable and unfavorable responses after 1 week was more pronounced after 2 weeks (t test, p < 0.01 vs. < 0.001). Diastolic indexes and pericardial effusion at 2 weeks seemed to be predictive of therapeutic response.
CONCLUSIONS: Poor sensitivity to mild rejection indicates that serial echocardiography cannot supplant endomyocardial biopsy in the early diagnosis of acute rejection, but it seems to be a reliable noninvasive means of identifying acute rejection requiring intensified immunosuppressive therapy and of evaluating outcome.