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Updated: Aug 18, 2026
A Rodent Model of The Ross Operation: Syngeneic Pulmonary Artery Graft Implantation in A Systemic Position
Published on: April 1, 2022
Oversizing pulmonary homograft conduits does not significantly decrease allograft failure in children
Tara Karamlou1, Ross M Ungerleider, Bahaaldin Alsoufi
1Division of Pediatric Cardiothoracic Surgery, Doernbecher Children's Hospital, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Mail Code DC8S, Portland, OR 97239, USA.
Insights
Placing oversized pulmonary ventricle-pulmonary artery (PV-PA) homografts does not improve longevity in children. Normalizing conduit size to body surface area (BSA) offers excellent outcomes, even in young patients requiring extracardiac allografts.
Area of Science:
- Pediatric Cardiac Surgery
- Congenital Heart Disease Repair
- Vascular Grafting
Background:
- Pulmonary ventricle-pulmonary artery (PV-PA) conduits are crucial for treating congenital heart defects.
- Oversizing these conduits is a common practice to anticipate somatic growth and prevent early failure.
- Recent evidence questions whether somatic growth is the primary driver of conduit failure in pediatric patients.
Purpose of the Study:
- To evaluate the impact of oversized homografts on the longevity of extracardiac pulmonary ventricle (PV) outflow tract reconstruction in young children.
- To determine if normalizing conduit size to body surface area (BSA) influences outcomes in pediatric patients.
Main Methods:
- A retrospective review of 102 consecutive PV-PA conduits in 70 patients under 18 years (1984-2003).
- Conduits were stratified by age (<10 years vs. >10 years) and size (oversized vs. non-oversized based on z-value).
- Analysis of conduit failure determinants and allograft longevity, comparing oversized and non-oversized groups.
Main Results:
- Oversizing homografts showed no significant advantage in freedom from replacement at 1, 5, or 10 years (96% vs. 93%, 79% vs. 60%, 21% vs. 24%).
- Conduit failure was more frequent in younger patients (<10 years) and in the oversized group (49% reoperation rate).
- In patients under 10, explantation rates and time to failure were similar between oversized and non-oversized conduits.
Conclusions:
- Placement of oversized PV-PA homografts does not offer significant benefits for conduit longevity in pediatric patients.
- Normalizing extracardiac allografts to BSA provides excellent conduit longevity and outcomes, even in pediatric patients with rapid somatic growth.
Objective:
Placement of oversized pulmonary ventricle-pulmonary artery conduits is routinely performed to decrease conduit failure in children. However, this practice has recently been challenged as somatic outgrowth may not be the main determinant of allograft failure in children. Our objective was to determine whether placement of oversized homografts for extracardiac pulmonary ventricle (PV) outflow tract reconstruction improves longevity in young children.
Methods:
We reviewed 102 consecutive PV-PA conduits inserted in 70 patients less than 18 years between 1984 and 2003. Conduits placed in an anatomic position (n=23) as part of a Ross operation, were excluded. Conduits were initially stratified into two age groups: Group 1, those placed in patients
Results:
Seventy-nine extracardiac conduits were placed, and 57 of these were in patients under 10 years of age. The majority had a diagnosis of tetralogy of Fallot (n=38), truncus arteriosus (n=19), pulmonary atresia with ventricular septal defect (n=12), or D-TGA with pulmonary stenosis and ventricular septal defect (n=7). Thirty-seven conduits were oversized (O/S) based on z-value, and 42 were non-oversized (NO/S), and the mean age at initial homograft placement was 7.0+/-7.5 years. Overall, oversizing conferred no significant advantage with respect to actuarial freedom from homograft replacement at 1, 5, or 10 years (96, 79, and 21%, O/S vs 93, 60, and 24%, NO/S), P=0.44. Oversizing was more frequent in Group 1 than Group 2 (53 vs 32%), and conduit failure was also more frequent with 49% requiring reoperation during the study period vs 38% in Group 2. In the subset of patients
Conclusions:
There is no significant benefit to placement of an oversized PV-PA homograft in this series of patients from a single institution. Even in young patients with rapid somatic growth, normalizing extracardiac allografts to BSA provides excellent conduit longevity and outcomes.
