AORTIC COARCTATION: RECENT DEVELOPMENTS IN EXPERIMENTAL AND COMPUTATIONAL METHODS TO ASSESS TREATMENTS FOR THIS SIMPLE CONDITION

Abstract

Coarctation of the aorta (CoA) is often considered a relatively simple disease, but long-term outcomes suggest otherwise as life expectancies are decades less than in the average population and substantial morbidity often exists. What follows is an expanded version of collective work conducted by the authors' and numerous collaborators that was presented at the 1st International Conference on Computational Simulation in Congenital Heart Disease pertaining to recent advances for CoA. The work begins by focusing on what is known about blood flow, pressure and indices of wall shear stress (WSS) in patients with normal vascular anatomy from both clinical imaging and the use of computational fluid dynamics (CFD) techniques. Hemodynamic alterations observed in CFD studies from untreated CoA patients and those undergoing surgical or interventional treatment are subsequently discussed. The impact of surgical approach, stent design and valve morphology are also presented for these patient populations. Finally, recent work from a representative experimental animal model of CoA that may offer insight into proposed mechanisms of long-term morbidity in CoA is presented.

Figure 1

Spatial patterns of time-averaged WSS for an 11 yo female patient with CoA treated surgically by resection with end-to-end anastomosis repair (right) and an age and gender matched control subject (left).

Figure 2

Spatial patterns of time-averaged WSS for a 26 yo male patient with CoA treated surgically by Dacron patch aortoplasty (right) and an age and gender matched control subject (left).

Figure 3

Time-averaged WSS results obtained from CFD models containing computational representations of two stents commonly used to treat CoA. The results reveal differences in low time-averaged WSS along the anterior wall and regions of elevated time-averaged WSS along the posterior wall of the descending thoracic aorta distal to the stents.

Figure 4

Representative mean intensity projections obtained from MRI angiography of the thoracic aorta of rabbits under several experimental conditions (top) with examples of corresponding CFD models (below). The experimental MRI protocol mirrors the protocol for obtaining the human MRI data used to create the CFD models shown above.