Cell-free human heart valves are always implanted with a more or less long piece of the adjacent vessel (ascending aorta, truncus pulmonalis) that carries the valve.
No cellular immunogenicity
Neumann et al (2014) examined the peripheral blood of 47 patients who received cell-free pulmonary valves over a period of three years. No elevated levels of T cells (CD3+, CD8+), B cells (CD19+), killer cells (CD16+/CD56+) or T helper cells (CD4+) could be detected. The cell-free pulmonary valves were immunologically silent.
“Early Systemic Cellular Immune Response in Children and Young Adults Receiving Decellularized Fresh Allografts for Pulmonary Valve Replacement”
Sarikouch et al (2019) investigated the postoperative immigration of cells into decellularized allograft. The relative histologic score (100% corresponds to complete cellular restoration) in samples that did not exhibit endocarditis (n=6) was 76±4%. Intracellular procollagen type 1 was found in the mesenchymal recipient cells. In endocarditis samples (n=5), the histological score was significantly lower at 48±7%, associated with leukocyte infiltration and matrix degradation. A cell-free pulmonary valve showed an immune system related graft failure. Allografts sampled in the first 12 months post-op showed a thin colonization of the media. In terms of the degree of restoration, no difference was found between a cell-free aortic or pulmonary heart valve.
“Early Insight Into In Vivo Recellularization of Cell-Free Allogenic Heart Valves”
Cell-free pulmonary valve
Boethig et al (2019) describes a total of 235 patients, 121 of whom were prospectively included in the multicenter ESPOIR observational study (2014-2016). The study group was compared with similar cohorts (propensity-matched) who received a conventional allograft or bioprosthesis. Decellularized allografts showed fewer adverse events than the control groups during the observation period.
“A European study on decellularized homografts for pulmonary valve replacement: initial results from the prospective ESPOIR Trial and ESPOIR Registry data”
Cell-free aortic valve
Horke et al (2020) describes a total of 223 patients, 144 of whom were prospectively enrolled in the multicenter ARISE observational study (2015-2018). The study group was compared with similar cohorts (propensity-matched) who received conventional heart valve prostheses or underwent "Ross surgery". Decellularized allografts showed fewer adverse events than the control groups during the observation period. Cell-free human aortic valves with a long vascular component are a therapeutic alternative for valve replacement in combination with the replacement of a dilated ascending aorta (Tudorache 2016).
“Early results form a prospective, single-arm European trial on decellularized allografts for aortic valve replacement: the ARISE study and ARISE Registry data”
Cell-free aortic valve for children
A subgroup analysis of young patients (10±5 years) describes the cell-free aortic valve as a beneficial therapeutic alternative to conventional prostheses (Horke et al. (2020-2).
"Paediatric aortic valve replacement using decellularized allografts
“Paediatric aortic valve replacement using decellularized allografts”
Replacing the aortic and pulmonary valve
Cell-free human heart valves are also suitable for double valve replacement. Since the cell-free design leads to less rejection, matching heart valves from different donors can be implanted (Bobylev 2019).
“Double semilunar valve replacement in complex congenital heart disease using decellularized homografts.”