Compliance of the Ascending Aorta After Aortic Root Replacement with a Decellularized Aortic Homograft—An MRI Study

Background: Local compliance of the ascending aorta may be assessed by means of relative area change (RAC) between systole and diastole. Reduced compliance (increased local stiffness) as reflected by RAC may result from both reduced elasticity or other “stiffening” vessel wall changes, impacting on overall cardiovascular function. Magnetic resonance imaging (MRI) derived parameters such as relative area change (RAC) and pulse wave velocity (PWV) may be used as surrogate parameters for the assessment of vessel compliance. We sought to determine whether long decellularized aortic homografts (DAH) exhibit similar compliance and flow variables compared with the healthy aorta of a control group.

Methods: 13 male patients with long DAH implantation were matched according to the age of the homograft donor (median age 42 years, IQR 32–50 years) to 7 healthy controls (median age 40 years, IQR 36–48 years). Two- and three-dimensional phase-contrast cardiac MRI (4D MR Flow) were used to measure RAC in various planes of ascending aorta, as well as maximum blood flow velocity (Vmax) and pulse wave velocity (PWV).

Results: The mean time between surgery and cardiovascular magnetic resonance imaging in the DAH group was 2.89 ± 1.94 years. The RAC in the proximal ascending aorta (PAA) was significantly lower in the DAH group (19 ± 4%) compared with healthy controls (38 ± 14%, p < 0.001), with no significant difference observed in the distal ascending aorta (22% [IQR 22–33] versus 34% [IQR 22–41], p = 0.588). Vmax in the PAA was significantly higher in the DAH group at 168 cm/s (IQR 148–188) compared with healthy controls at 115 cm/s (IQR 114–120, p = 0.009). No significant differences were found for Vmax at the level of the aortic valve (170 ± 47 cm/s versus 142 ± 17 cm/s, p = 0.172) and at the level of the distal ascending aorta (156 [IQR 145–190] cm/s versus 118 [IQR 116–174] cm/s, p = 0.384). No significant differences were found for pulse wave velocity, 5.11 (IQR 4.17–8.05) m/s in the DAH group versus 4.53 (IQR 3.79–6.99) m/s in healthy controls (p = 0.536).

Conclusion: We observed evidence for reduced regional aortic compliance in the proximal ascending aorta of the decellularized homograft (DAH) group compared with donor age-matched healthy controls. This suggests that either the decellularization process itself or degenerative effects may induce localized changes in the graft. This finding underscores the need for thorough follow-up to better understand the long-term in-vivo effects of decellularized human tissue.

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Artikel online veröffentlicht:
11. Februar 2025