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Indexed/Abstracted in: BIOSIS Previews, Current Contents/Clinical Medicine, EMBASE, PubMed/MEDLINE, Science Citation Index Expanded (SciSearch), Scopus
Impact Factor 1,632
Online ISSN 1827-191X
Chitsaz S. 1, Azadani A. N. 1, Matthews P. B. 1, Chuter T. A. 2, Tseng E. E. 1, Ge L. 1
1 Division of Cardiothoracic Surgery, Department of Surgery, University of California at San Francisco Medical Center and San Francisco VA Medical Center, San Francisco, CA, USA;
2 Division of Vascular Surgery, Department of Surgery, University of California at San Francisco Medical Center and San Francisco VA Medical Center, San Francisco, CA, USA
Aim. Aortic dissection is a life-threatening aortic catastrophe where layers of the aortic wall are separated allowing blood flow within the layers. Propagation of aortic dissection is strongly linked to the rate of rise of pressure (dp/dt) experienced by the aortic wall but the hemodynamics is poorly understood. The purpose of this study was to perform computational fluid dynamics (CFD) simulations to determine the relationship between dissection propagation in the distal longitudinal direction (the tearing force) and dp/dt.
Methods. Five computational models of aortic dissection in a 2D pipe were constructed. Initiation of dissection and propagation were represented in 4 single entry tear models, 3 of which investigated the role of length of dissection and antegrade propagation, 1 of which investigated retrograde propagation. The 5th model included a distal re-entry tear. Impact of pressure field distribution on tearing force was determined.
Results. Tearing force in the longitudinal direction for dissections with a single entry tear was approximately proportional to dp/dt and L2 where L is the length of dissection. Tearing force was much lower under steady ﬂow than pulsatile ﬂow conditions. Introduction of a second tear distally along the dissection away from the primary entry tear signiﬁcantly reduced tearing force.
Conclusion. The hemodynamic mechanism for dissection propagation demonstrated in these models support the use of β-blockers in medical management. Endovascular stent-graft treatment of dissection should ideally cover both entry and re-entry tears to reduce risk of retrograde propagation of aortic dissection.