The functional limits of the aneurysmal aortic root. A unique pressure testing apparatus

Area of Science:

• Cardiovascular Research
• Biomedical Engineering
• Thoracic Surgery

Background:

• The aortic root's unique development is often overlooked in biomechanical studies of the thoracic aorta.
• Existing research lacks distinction between the aortic root and ascending aorta in biomechanical assessments.
• Aortic aneurysms pose significant risks, necessitating better understanding of tissue failure points.

Purpose of the Study:

• To compare maximal pressures causing tissue failure in the aortic root versus the ascending aorta.
• To investigate dissection occurrence and propagation in aneurysmal aortic root tissue.
• To provide data for improved preoperative monitoring and surgical intervention decisions for aortic aneurysms.

Main Methods:

• A custom pressure testing unit was developed to evaluate aortic root and ascending aorta specimens.
• Artificial aneurysms were created in porcine aortic root intima-medial layers.
• Progressive saline filling measured pressure at tissue failure, dissection, or rupture, followed by visual examination.

Main Results:

• Aortic root tissue failure occurred at a mean maximal pressure of 208 mmHg.
• Dissection propagated circumferentially in all aortic root specimens, with coronary ostia tears in 2/5.
• Ascending aorta specimens exceeded 300 mmHg without failure, indicating greater structural integrity.

Conclusions:

• Aneurysmal aortic root tissue exhibits higher susceptibility to rupture and dissection at lower pressures.
• These findings suggest a critical need for distinct clinical and surgical management strategies for aortic root aneurysms.
• Further research can refine clinical guidance and surgical interventions for aortic root pathologies.