USEFULNESS OF LEFT-VENTRICULAR INFLOW DOPPLER IN PREDICTING REJECTION IN PEDIATRIC CARDIAC TRANSPLANT RECIPIENTS

Interest in a noninvasive technique to diagnose rejection in pediatric cardiac transplant recipients is high because of the time, cost and potential for morbidity associated with endomyocardial biopsy.1-3 Because the onset of rejection is associated with altered myocardial compliance, the potential for noninvasive assessment of left ventricular (LV) diastolic dysfunction as an early marker for rejection has been considered.4-7 Several studies have shown changes in the pattern of LV filling velocities as assessed by Doppler echocardiography during rejection.8-10 Despite differences in filling patterns between those with and without rejection on cardiac biopsy, the ability of Doppler-derived LV filling measures to either predict the results of biopsy or identify a high-risk group requiring biopsy remains controversial. Transplanted hearts present potential physiologic confounders that limit the usefulness of LV inflow Doppler measurements. These include alterations in atrioventricular synchrony (PR interval prolongation or ineffective atria1 contraction), atria1 dilatation, LV hypertrophy and systemic hypertension.11-13 Some investigators have suggested that the predictive value of LV inflow parameters is improved when each person serves as his own control.8 Rather than establish normal values for LV filling from a cross section of transplant recipients with negative results on myocardial biopsy, a normal LV filling pattern is established for each patient. We hypothesized that LV filling velocities would be altered during rejection, these abnormalities would be best appreciated by intraindividual comparison, and that intra- and interob-server measurement variability may account for difficulty in the clinical application of LV filling characteristics. © 1994.