The clinical value of blunting of cyclic gray level variation for the detection of acute cardiac rejection: a two-dimensional, Doppler, and videodensitometric ultrasound study.

Aims of this study were to assess (1) whether videodensitometric analysis of myocardial gray-level variation can distinguish normal from rejecting transplanted hearts in a clinical setting and (2) whether this sign, used in combination with the other conventional two-dimensional and Doppler echocardiographic findings, might improve the accuracy of ultrasound techniques. Thirty heart transplant recipients (23 men; mean age 40 years; range 20 to 54 years) were studied in 87 different situations by endomyocardial biopsy and echocardiographic evaluation. Of the 87 situations, 37 ("rejectors") showed histologic evidence of rejection of mild (n = 17) or moderate (n = 10) severity and 50 ("nonrejectors") did not show rejection processes. Cyclic variation was decreased significantly in rejectors compared with nonrejectors in both the septum (15% +/- 10% versus 25% +/- 11%; p < 0.0001) and the posterior wall (19% +/- 10% versus 25% +/- 12%; p < 0.01). When a cutoff of 20% or greater of cyclic variation in the septal wall was taken as a positivity criterion, it yielded a 70% sensitivity and 70% specificity for identifying rejection. Sensitivity of conventional two-dimensional and Doppler echocardiographic signs was 51% and increased to 89%, increased by the videodensitometric criteria (p < 0.001). Specificity was 92% and decreased to 62% with videodensitometric criteria (p < 0.001). Overall diagnostic accuracy was 75% for conventional two-dimensional echocardiographic Doppler criteria alone and remained unchanged by the addition of videodensitometric criteria. In conclusion, blunting of cyclic gray-level variation induced by rejection is detectable with videodensitometric analysis. The clinical impact of this sign appears to be limited, because the resulting increase in sensitivity is counter-balanced by a reduced specificity compared with the currently available conventional ultrasound techniques.