Can Long Decellularized Homografts Restore Normal Blood Flow in the Ascending Aorta? A 4D-Flow CMR Study

Objectives: Implantation of long valved decellularized aortic homografts (DAH) may constitute a new option to treat aortic valve disease associated with aorta ascendens dilatation as it avoids the use of any prosthetic material or anticoagulation.

Methods: Patients following implantation of long DAH ( n = 11, 34 ± 10 years) were compared with patients after valve sparing aortic root replacement (VSARR, n = 11, 40 ± 13 years) and normal healthy controls (n = 11, 33 ± 9 years), only males were included. Time-resolved three-dimensional phase-contrast cardiac magnetic resonance imaging (4D flow CMR) was performed to assess maximum velocity (MV), pulse wave velocity (PWV), relative area change (RAC), mechanical energy loss (EL), wall shear stress (WSS), and flow patterns (vorticity, eccentricity, helicity) throughout five planes of the whole thoracic aorta (1—aortic valve, 2—AAO, 3—before Truncus br., 4—distal A. subclavia, 5—DAO).

Result: Mean time between surgery and CMR was 2.56 ± 2.0 years in DAH versus 2.67 ± 2.1 years in VSARR. There was no significant difference in maximum velocities between controls (134.82 ± 53.90 cm/s) and DAH (141.98 ± 33.95 cm/s, p = 0.58) in all five planes. Velocity in plane 3 was significantly increased in VSARR (182.91 ± 38.65 cm/s, p = 0.03).

PWW was lower in DAH (9.22± 2.35 m/s, p = 0.06) than in VSARR (10.65 ± 5.72 m/s, p = 0.06); however, differences to controls were not significant (7.43 ± 1.55 m/s). Relative area change in DAH was almost identical to those of the control group (27 ± 0.2 vs. 24 ± 0.1%, p = 0.99) in AAO and better than in VSARR (16 ± 0.1%, p = 0.13). There was no significantly difference in EL between ascending aorta and descending aorta in controls (5.0 mW) and DAH (7.95 mW, p = 0.11), EL was significantly increased in VSARR (12.22 ± 7.48 mW, p = 0.006).

There were no significant differences in wall shear stress parameters in all five regions of the thoracic aorta in all three groups. DAH patients showed more vorticity (1.36 ± 0.67 vs. 0.27 ± 0.47, p = 0.006), helicity (1.36 ± 0.50 vs. 0.18 ± 0.40, p = 0.0008), and eccentricity (1.36 ± 0.67 vs. 0.3 ± 0.40, p = 0.0006) in the ascending aorta compared with control group.

Conclusion: Decellularized long aortic homografts exhibit favorable hemodynamic parameters 2.5 years postoperatively. In patients with aortic valve pathology and associated dilated AAO, where preservation of the aortic valve is not feasible, extended aortic valve replacement using long decellularized aortic homografts may be an additional surgical option.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
19 February 2021