Non-invasive detection of acute allograft rejection in children by tissue Doppler imaging: myocardial velocities and myocardial acceleration during isovolumic contraction.
BACKGROUND
In adults, an acute decrease of regional myocardial velocities is a sensitive marker of rejection. In children, velocities are more variable. A new marker, myocardial acceleration during isovolumic contraction (IVA), appears to be less age-dependent than myocardial velocities. This study therefore compared tissue Doppler (TDI)-derived velocities and IVA as potential rejection markers for children.


METHODS
TDI was performed in 15 pediatric heart transplant recipients (age 8.0 +/- 3.6 years) during acute rejection and at baseline without rejection, 50 additional transplant children without rejection (7.8 +/- 5.9 years) and 30 age-matched healthy children (7.5 +/- 5.2 years). Color Doppler cine-loops of 3 cardiac cycles were stored as echocardiographic raw data. Using off-line post-processing, systolic (S) and diastolic (E) myocardial velocities and IVA were measured in 5 basal left ventricular segments. IVA is the peak isovolumic contraction wave velocity divided by acceleration time.


RESULTS
Without rejection, transplant children had significantly lower diastolic velocities (basal lateral E 10.4 +/- 2.9 vs 11.9 +/- 2.6 cm/s; p < 0.001) and systolic velocities (S 5.6 +/- 1.4 vs 7.1 +/- 2.0 cm/s; p < 0.001) than normal age-matched controls, but IVA was similar (1.2 +/- 1.4 vs 1.3 +/- 0.5 m/s2). During rejection, all markers decreased significantly compared with age-matched normal control, the non-rejecting transplant group and individual baseline values.


CONCLUSIONS
Regional myocardial velocities change significantly during acute allograft rejection in children. However, many children already have wall motion abnormalities at baseline, so results are often difficult to interpret. In contrast, isovolumic acceleration was normal without rejection and selectively decreased during the event. IVA is a promising non-invasive rejection marker for pediatric patients.
Tufts-New England Medical Center, Boston, Massachusetts 02111, USA. lpauliks@tufts-nemc.org
Linda B
LB
Pauliks
Biagio A
BA
Pietra
Curt G
CG
DeGroff
Kenneth Scott
KS
Kirby
Ole A
OA
Knudson
Loralee
L
Logan
Mark M
MM
Boucek
Lilliam M
LM
Valdes-Cruz
D001783:Blood Flow Velocity / Q000502:physiology; D002648:Child; D002675:Child, Preschool; D015150:Echocardiography, Doppler; D006084:Graft Rejection / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D006321:Heart / Q000503:physiopathology*; D016027:Heart Transplantation / Q000276:immunology / Q000502:physiology*; D006801:Humans; D009200:Myocardial Contraction / Q000502:physiology*; D014184:Transplantation, Homologous; D016277:Ventricular Function, Left