Durability of pulmonary homografts for reconstruction of the right ventricular outflow tract: how relevant are donor-related factors?

Objectives: Our goal was to evaluate the influence of donor-related factors on the durability of pulmonary homografts (PHGs) for right ventricular outflow tract reconstruction of congenital heart defects.

Methods: Between 1990 and 2016, 223 PHGs were used in 197 patients for right ventricular outflow tract reconstruction. Long-term durability was investigated in relation to patient- and disease-specific as well as to donor-related factors, based on the PHG replacement rate. To minimize the effect of outgrowth, a subgroup analysis was performed on patients with PHG size >22 mm, as the discriminant cut-off identified by the classification tree method.

Results: During a median follow-up of 8.5 years [interquartile range (IQR) 12.3], 47 (21%) PHGs were explanted within a mean interval of 9.5 ± 5.3 years, resulting in a freedom from PHG replacement of 82 ± 6% at 10 years. The risk factors for PHG explantation determined by univariable analysis were predominantly patient-related, including younger age (P = 0.003), extra-anatomic implantation (P = 0.006), bicuspidalization (P = 0.002) and younger donor age (P = 0.032). PHG size [hazard ratio (HR) 0.80, 95% confidence interval 0.73-0.88; P < 0.001] was the only independent determinant in multivariable analysis. The subgroup analysis comprised 119 PHG >22 mm, implanted at a median age of 15 years (IQR 7). A significant beneficial effect of ABO matching on the explantation rate was only identified with univariable analysis (HR 0.24, 95% confidence interval 0.12-4.68; P = 0.010).

Conclusions: Cryopreserved PHGs provide a durable substitute for right ventricular outflow tract reconstruction in congenital heart disease. PHG size at the time of implantation remains the principal determinant of PHG explantation during late follow-up. However, once an adult-sized homograft is required, matching for ABO blood group compatibility between host and donor might help to improve homograft durability.