Blood flow helical pattern in type III arch configuration as a potential risk factor for type B aortic dissection

Area of Science:

• Cardiovascular fluid dynamics
• Medical imaging analysis
• Aortic pathology

Background:

• Abnormal helical flow (HF) in the aortic arch is implicated in aortic dilatation and dissections (AD).
• Type B AD patients frequently exhibit a type III arch, a known anatomical risk factor for AD.
• Understanding the HF patterns associated with different arch configurations is crucial for risk stratification.

Purpose of the Study:

• To investigate if the type III aortic arch configuration consistently produces a specific secondary helical flow (HF) pattern.
• To compare HF characteristics between type I, II, and III aortic arch configurations using computational fluid dynamics.

Main Methods:

• Computational fluid dynamics (CFD) simulations were used to analyze HF in aortic arch models.
• Flow pathlines were extracted and characterized by curvature (|κ|) and torsion (|τ|) indices.
• Local normalized helicity was computed and mapped onto flow pathlines within the Modified Arch Landing Areas Nomenclature (MALAN) regions.

Main Results:

• The type III arch (MALAN 3/III) exhibited significantly increased pathline curvature (|κ|) and decreased torsion (|τ|), indicating persistent, high-rotational HF.
• Local normalized helicity was found to be higher in the type III arch (3/III) compared to type I (3/I) and type II (3/II) arches.
• These findings demonstrate a consistent and abnormal HF pattern specifically associated with the type III arch configuration.

Conclusions:

• The type III aortic arch configuration is linked to a unique and abnormal secondary helical flow (HF) pattern.
• This distinct HF pattern may contribute to the high prevalence of type III arches in patients suffering from type B aortic dissection (AD).
• Further research into HF dynamics could improve risk assessment and treatment strategies for aortic diseases.