Intracoronary ultrasound imaging in heart transplant recipients: the Stanford experience.
Explore the source record for details and available documents.
Coronary Disease↗
Biomedical subjects
R L Popp
Publications and source records attributed to R L Popp.
Sensitivity and specificity of diastolic indexes for rejection surveillance: temporal correlation with endomyocardial biopsy.
Although acute diastolic dysfunction is an early sequela of the rejecting heart, reported sensitivities and specificities have varied widely when Doppler echocardiography is used for rejection surveillance. This study examines the temporal relationship between changes in Doppler echocardiographic indexes of diastolic function and sequential endomyocardial biopsies to identify possible factors accounting for false-positive and false-negative results. A total of 114 Doppler echocardiographic studies and biopsies were performed weekly in 39 patients aged 14 to 59 years during the initial 3 months after heart transplantation. All Doppler examinations were within 24 hours of biopsy and were analyzed in a blinded fashion. Onset of restrictive physiology, defined as a 15% decrease in either isovolumic relaxation time or pressure half-time, was determined by analysis of the Doppler mitral flow velocity curve.
Adolescent↗
Ultrasonic characterization of acute cardiac rejection from temporal evolution of echocardiograms.
Two ultrasonic parameters that characterize cardiac contractile performance were tested for their ability to detect the early stages of acute rejection. Five dogs received heart transplants with a heterotopic abdominal model and were given echographic examinations 1, 4, and 8 days after surgery. The ultrasonic measurements were extracted from pairs of cross-sectional echocardiograms, separated in time by approximately half of a cardiac cycle. The contraction-related changes in the portions of the images corresponding to myocardium were characterized by ratio of mean video amplitude and image-pair correlation. Full-thickness biopsies were taken from the left and right ventricles after each examination so that the correlations between the ultrasonic measurements and the histologic state of the tissue could be determined. Each biopsy was ranked according to the following scale of increasing levels of rejection: 0 (normal), 1 (lymphocyte infiltration), 2 (focal necrosis), 3 (diffuse necrosis), 4 (presence of hemorrhages). The average histologic state for the left ventricle increased from 0.2 +/- 0.4 for the first examination, to 2.0 +/- 0.7 for the second, and 3.6 +/- 0.5 for the third. Similar results were obtained for the right ventricle. The progressions of mean amplitude ratio and correlation were 1.55 +/- 0.14, 1.49 +/- 0.17, 1.19 +/- 0.15, and 0.22 +/- 0.10, 0.28 +/- 0.10, 0.74 +/- 0.25, respectively. Thus in this experiment, these parameters were useful for distinguishing advanced stages of rejection from the normal state and from mild rejection.
Animals↗