What is the relationship between Aortic Regurgitation (AR) and aortic dissection?

From the Guidelines

Aortic Regurgitation (AR) is closely related to aortic dissection, as abnormalities of the aorta, primarily aortic dissection, can cause acute AR.

Relationship Between AR and Aortic Dissection

• Aortic dissection is a primary cause of acute AR, highlighting the importance of considering aortic root disease in the management of AR patients 1.
• The relationship between AR and aortic dissection is bidirectional, as severe AR can also lead to aortic dilatation, increasing the risk of dissection 1.
• In patients with AR, the presence of aortic root disease, such as Marfan syndrome or bicuspid aortic valve, requires careful consideration of the aortic diameter and the risk of dissection 1.

Management of AR and Aortic Dissection

• In patients with severe AR and aortic dilatation, surgery is often indicated, with the goal of repairing or replacing the aortic valve and reconstructing the aortic root 1.
• The decision to operate on the ascending aorta in patients with AR should take into account the shape and thickness of the aorta, as well as the presence of other aortic diseases 1.
• In asymptomatic patients with severe AR and impaired left ventricular function, surgery should be considered to prevent the development of symptoms and improve outcomes 1.

Key Considerations

• Aortic diameter is a critical factor in the management of AR patients, with thresholds for surgery varying depending on the underlying condition, such as Marfan syndrome or bicuspid aortic valve 1.
• The choice of surgical technique should be adapted to the individual patient's characteristics, including the presence of associated root aneurysm, leaflet characteristics, and underlying pathology 1.

From the Research

Relationship between Aortic Regurgitation (AR) and Aortic Dissection

The relationship between Aortic Regurgitation (AR) and aortic dissection is complex and has been studied in various research papers. Some key findings include:

• Disruption of the aortic root by dissection often produces significant aortic regurgitation (AR) 2.
• The degree of dissection of the valve annulus is the most significant determinant of leaflet prolapse and AR severity 2.
• Surgical resuspension significantly decreases root size, but its primary benefit is restoration of the structural integrity of the aortic annulus 2.
• Transesophageal echocardiography (TEE) can define the severity and mechanisms of AR and can assist the surgeon in identifying patients in whom valve repair is likely to be successful 3.

Mechanisms of Aortic Regurgitation in Aortic Dissection

The mechanisms of AR in aortic dissection include:

• Incomplete leaflet closure due to leaflet tethering in a dilated aortic root 3.
• Leaflet prolapse due to disrupted leaflet attachments 3.
• Dissection flap prolapse through the aortic valve orifice 3.
• Pseudo-aortic regurgitation, where regurgitation flow exists just in the area surrounding the intimal flap during diastole 4.

Predictors of Significant Aortic Regurgitation

Predictors of significant AR after ascending aortic replacement in patients with acute type A aortic dissection include:

• Preoperative ≥3+ AR 5.
• Postoperative ≥2+ AR 5.
• False to true lumen ratio 5.

Comparison of Aortic Regurgitation and Aortic Stenosis

Comparison of ascending aortic cohesion between patients with bicuspid aortic valve stenosis and regurgitation showed that:

• Patients with AR had significantly worse aortic cohesion, as measured by shear stress testing 6.
• Patients with AR had a thicker aortic wall and a larger aortic root compared to those with AS 6.