Bicuspid Ascending Aortic Aneurysms Exhibit Increased Dissection Resistance: An Ex Vivo Analysis

Area of Science:

• Cardiovascular Biology
• Biomedical Engineering
• Aortic Disease Research

Background:

• Ascending thoracic aortic aneurysms (ATAAs) with bicuspid aortic valves (BAVs) are often assumed to be more vulnerable than those with tricuspid aortic valves (TAVs).
• Understanding the biomechanical properties of ATAAs is crucial for predicting dissection risk.

Purpose of the Study:

• To compare the delamination resistance of ATAAs associated with BAVs versus TAVs.
• To investigate the biomechanical differences underlying aortic dissection in BAV- and TAV-ATAAs.

Main Methods:

• Intraoperative harvesting of whole ATAAs from patients undergoing elective repair.
• Sectioning specimens into circumferential and longitudinal strips for delamination and tensile testing.
• Histological analysis of the delamination plane surface roughness.

Main Results:

• BAV-ATAAs exhibited significantly greater delamination strength than TAV-ATAAs across all quadrants.
• Histological analysis showed a rougher peeling surface in BAV-ATAAs.
• The left lateral quadrant demonstrated increased resistance, particularly in TAV-ATAAs, suggesting regional biomechanical variations.

Conclusions:

• BAV-ATAAs demonstrated superior resistance to dissection propagation compared to TAV-ATAAs in ex vivo testing.
• These findings challenge the notion of intrinsic structural fragility in BAV aortopathy.
• Results align with emerging clinical observations regarding BAV-associated aortic disease.