Eastern Cardiothoracic Surgical Society

Computational Fluid Dynamics Wall-Stress Assessment of Root, Ascending Aorta and Arch Supports  the Preservation of the Dissected Arch with Treatment of Type-A Dissections
Domenico Calcaterra1, Liza Shrestha2, Mohammad Bashir2, Kalpaj Parek2,  1Hennepin Medical Center, Minneapolis, MN, USA, 2University of Iowa, Iowa City, IA

OBJECTIVE: A persistent controversy exists in the literature in relation to the need to proceed with total arch replacement in type-A dissections with arch involvement. Total arch replacement in the setting of type-A dissection carries high morbidity and mortality. Observational studies and some experts’ opinion seem to suggest that preserving the arch and performing hemiarch reconstruction offers the best results without exposing to the possible risks associated with a total arch replacement. Using computational fluid dynamics assessment we aim at providing the scientific bases in support of the choice for this surgical strategy.

METHODS: We reviewed 74 consecutive patients treated for acute type-A dissection in a 8-year period. Sixty-two patients (83.7%) had distal aortic involvement (DeBakey type-1).

RESULTS: Of the 62 patients surgically treated for DeBakey type-1, 4 (6.4%) had a total arch replacement. Thirty-day mortality was 14.5% (9). A mean follow up of 40 months was completed on 46 patients. One patient (1.6%) required reoperation of total arch replacement and 4 patients (6.5%) required distal thoracic aortic replacement. Using computational fluid dynamics simulation on an idealized model of the aorta we determined that pressure distribution, wall-shear stress and velocity magnitude are all greater in the root and ascending aorta compared to the arch (Figure SA9-1).

CONCLUSIONS: Computational fluid dynamic model of aortic flow shows that the aortic arch is subject to less hemodynamic stress compared to ascending aorta and root. This finding supports the choice of preserving the uncomplicated dissected arch in the setting of aortic replacement for type-A dissection with arch involvement.

Figure SA-9-1
Computational Fluid Dynamics Assessment of Wall Stress
Distribution on an Idealized Aortic Model