Paediatric aortic valve replacement using decellularized allografts: a multicentre update following 143 implantations and five-year mean follow-up

Abstract

Objectives: Decellularized aortic homografts (DAH) were introduced in 2008 as a further option for paediatric aortic valve replacement (AVR).

Methods: Prospective, multicentre follow-up of all paediatric patients receiving DAH for AVR in 8 European centres.

Results: A total of 143 DAH were implanted between February 2008 and February 2023 in 137 children (106 male, 74%) with a median age of 10.8 years (interquartile range 6.6-14.6). Eighty-four (59%) had undergone previous cardiac operations and 24 (17%) had undergone previous AVR. The median implanted DAH diameter was 21 mm (interquartile range 19-23). The median operation duration was 348 min (227-439) with a median cardiopulmonary bypass time of 212 min (171-257) and a median cross-clamp time of 135 min (113-164). After a median follow-up of 5.3 years (3.3-7.2, max. 15.2 years), the primary efficacy end-points peak gradient (median 14 mmHg, 9-28) and regurgitation (median 0.5, interquartile range 0-1, grade 0-3) showed good results but an increase over time. Freedom from death/explantation/endocarditis/bleeding/thromboembolism at 5 years were 97.8 ± 1.2/88.7 ± 3.3/99.1 ± 0.9/100 and 99.2 ± 0.8%, respectively. Freedom from death/explantation/endocarditis/bleeding/thromboembolism at 10 years were 96.3 ± 1.9/67.1 ± 8.0/93.6 ± 3.9/98.6 ± 1.4 and 86.9 ± 11.6%, respectively. In total, 21 DAH were explanted. Seven were replaced by a mechanical AVR, 1 Ross operation was performed and a re-do DAH was implanted in 13 patients with no redo mortality. The calculated expected adverse events were lower for DAH compared to cryopreserved homograft patients (mean age 8.4 years), and in the same range as for Ross patients (9.2 years) and mechanical AVR (13.0 years).

Conclusions: This large-scale prospective analysis demonstrates excellent mid-term survival using DAH with adverse event rates comparable to paediatric Ross procedures.

Keywords: Allografts; Aortic valve disease; Children; decellularization.

Figure 1:

Freedom from explantation according to Kaplan–Meier with 95% confidence intervals and functional status of all implanted DAH in children. Displayed functional status frequencies refer to all DAH implanted in the respective period. Dashed boxes indicate years in which follow-ups in Moldovia could be performed only via telephone due to the COVID19 pandemic and the war in Ukraine. DAH: decellularized aortic homograft.

Figure 2:

Development of aortic valve gradients and regurgitation over time following DAH. We entered 1 value per patient-follow-up year, if necessary, linearly interpolated. DAH: decellularized aortic homograft.

Figure 3:

A 0.2-year-old boy, S/P 2 × aortic valve balloon valvuloplasty, AVR with DAH 10 mm in 2010 and redo AVR in 2015 with 17 mm DAH. Recent echo at 8 years following redo DAH implantation shows normal ventricular dimensions and function. Competent and pliable DAH cusps and a normal, untouched pulmonary valve. AVR: aortic valve replacement; DAH: decellularized aortic homograft.

Figure 4:

Paediatric DAH implanted to date in comparison with recently published meta-analysis data for several AVR options in children. Observed averaged rates for early and late adverse event category (± 95% confidence intervals) within the 4 different aortic valve substitutes. Ross results include right ventricular procedures [17]. DAH: decellularized aortic homograft. Data taken from: Notenboom et al. Eur Heart J. 2023 Jun 27.