Ventricular remodeling following infant-pediatric cardiac transplantation. Does age at transplantation or size disparity matter?

Early left ventricular (LV) remodeling following pediatric cardiac transplantation has not been described. To identify patterns and determinants of change in left ventricular mass and volume posttransplant, we studied 125 consecutive children who underwent cardiac transplantation between January 1, 1989 and July 31, 1993. Two-dimensional imaging-directed M-mode echocardiograms were studied weekly until 26 weeks post-transplant. LV mass and volume (indexed to BSA1.5) were measured. LV mass index increased until 3 weeks post-transplant, and then decreased. The mean decrement in LV mass index after 8 weeks post-transplant (relative to baseline) was significantly larger in patients with donor-recipient weight ratio > 1.5 compared with patients with donor-recipient weight ratio < or = 1.5 (-2.2 g/m3 compared with 33.4 g/m3, respectively, P < 0.01). Multiple linear regression was performed employing donor-recipient weight ratio, time since transplantation, ischemic time, and age at transplant as prognostic variables. Donor-recipient weight ratio (P < 0.0001), time since transplant (P < 0.01), and age at transplant (P = 0.02) were identified as independent predictors of change in LV mass index. Donor-recipient weight ratio (P = 0.001) and time since transplantation (P = 0.02) were independent predictors of change in LV volume index. There was an interaction between donor-recipient weight ratio and time since transplantation, suggesting that donor-recipient weight ratio has an independent effect as well as a time-dependent effect on change in LV mass and volume indices. LV mass and volume indices increased early posttransplant and then decreased; this pattern was temporally predictable, and dependent on donor-recipient weight ratio and age at transplant.