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Aortic root dilation refers to abnormal enlargement of the proximal aorta, including the aortic annulus, sinuses of Valsalva, and the sinotubular junction.

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It can lead to aortic regurgitation, predispose to aortic dissection, and is associated with genetic syndromes, connective tissue disorders, and valvular disease.

Anatomical Boundaries of the Aortic Root

Component	Description
Aortic annulus	Fibrous ring at the base of the aortic valve
Sinuses of Valsalva	Three bulging sinuses just above each aortic cusp
Sinotubular junction	Junction where aortic root becomes ascending aorta

Etiology

Genetic / Connective Tissue Disorders:

Condition	Feature
Marfan syndrome	FBN1 mutation; ascending aortic aneurysm, MVP
Loeys–Dietz syndrome	TGF-β pathway mutation; aggressive aneurysms
Ehlers–Danlos (vascular type)	COL3A1 mutation; fragile vasculature
Turner syndrome	Bicuspid aortic valve + CoA + root dilation

Valvular pathology

Valve Disease	Mechanism
Bicuspid aortic valve (BAV)	Aortopathy with dilation at root or ascending aorta
Chronic aortic regurgitation	Volume overload causing post-load remodeling

Other Causes

Hypertension
Syphilitic aortitis
Inflammatory aortitis (e.g., Takayasu arteritis)
Idiopathic aortopathy
Iatrogenic (post-surgery, prosthetic valve mismatch)

Radiology

Modality	Imaging features
Echo	• Measures: aortic annulus, sinuses of Valsalva, sinotubular junction, ascending aorta
• Identifies: Dilation, asociated aortic regurgitation and bicuspid valve
CTA/MRA	CTA is preferred in emergencies (e.g., suspected dissection). MRA is best for long-term surveillance (especially in young patients)

3D evaluation of: • Extent and morphology of dilation • Involvement of ascending aorta and arch |

Risk of Complications