Semilunar Valves in Pediatric Orthotopic Heart Transplants Grow at a Slower Rate than Controls

Area of Science:

• Pediatric Cardiology
• Cardiac Surgery
• Transplantation Medicine

Background:

• Partial heart transplantation utilizes a growing donor valve for pediatric recipients requiring valve replacement.
• Objective data on semilunar valve growth post-orthotopic heart transplantation (OHT) is needed to predict partial heart transplant graft growth.
• Understanding valve growth dynamics is essential for optimizing outcomes in pediatric cardiac procedures.

Purpose of the Study:

• To determine the growth rate of semilunar valves in infants following orthotopic heart transplantation (OHT).
• To compare semilunar valve annulus dimensions and Z-scores in OHT patients versus controls with ventricular septal defects (VSD).
• To provide data informing the expected growth trajectory of partial heart transplant grafts.

Main Methods:

• Retrospective cohort study including 12 infants undergoing OHT and 12 controls with VSD.
• Serial echocardiograms were used to measure semilunar valve annulus dimensions.
• Z-scores were calculated, and mixed-effects models analyzed absolute and scaled dimensions over time.

Main Results:

• Both aortic and pulmonary valve annuli in OHT patients demonstrated growth.
• Aortic valve annulus Z-scores showed a significant downward trend over time in OHT patients compared to controls (p=0.011).
• Pulmonary valve annulus Z-scores showed a non-significant downward trend in OHT patients (p=0.140); semilunar valves grew slower in OHT patients than controls.

Conclusions:

• Semilunar valves in pediatric OHT patients exhibit slower growth rates compared to controls.
• While the observed difference in growth may not be clinically significant for current OHT recipients, it provides vital information for partial heart transplantation.
• These findings help establish growth expectations for partial heart transplant grafts, aiding in surgical planning and patient management.