Non‐invasive parameters for detection of cardiac allograft rejection

Six non‐invasive parameters for detection of allograft rejection were evaluated in a series of 51 consecutive heart transplant recipients. All patients were treated with a triple‐drug regimen for immunosuppression, consisting of steroids, azathioprine and cyclosporine A. Three immunological and three functional parameters were compared with the results of endomyocardial biopsies (EMB). The number of activated lymphocytes in the peripheral blood was assessed by cytoimmunological monitoring (CIM) and correlated with EMB in 727 instances. In 154 of these, acute rejection was present, the sensitivity of CIM was 74.1%. Serum neopterine levels were assessed in 246 samples, 56 of which were obtained during acute rejection. The sensitivity of this assay was 50%. Antimyolcmmal antibodies (AMLA) were studied in 89 blood samples. Correlation with acute rejection on EMB disclosed a sensitivity of 67% for IgM and 65% for IgG subclasses of AMLA. Of the functional parameters studied, both intramyocardial electrogram (telemetry pacemaker system), and left ventricular ejection fraction (radionuclide ventriculography) showed poor correlations with EMB (47% and 39%, respectively). M‐mode echocardiography, by contrast, more reliably predicted acute rejection when assessing the isovolmetric relaxation period (sensitivity 78%). With the combined use of CIM and echocardiography, no acute rejection was missed in 9 instances (sensitivity 100%). It is concluded that more than one non‐invasive parameter is needed to accurately predict cardiac allograft rejection. The combined use of functional and immunological parameters appears advantageous.