Aortic arch atherosclerosis

Created 16/04/2023, last revision 26/05/2023

Anatomy

the aorta is the main and largest artery in the human body
it originates from the left ventricle and extends down to the abdomen, where it branches into the common iliac arteries and a small median sacral artery
it consists of these segments:
- ascending aorta
  - the origin of the coronary arteries in the aortic sinuses
- aortic arch
  - the arch has 3 major branches: the brachiocephalic trunk, the left common carotid artery, and the subclavian artery
  - aortic arch ends and the descending aorta begins approx. at the level of the Th4-5 intervertebral disc
- descending aorta (divided by the diaphragm at the level of Th12 into the thoracic and abdominal parts)
  - major thoracic branches: intercostal and subcostal arteries, the superior and inferior left bronchial arteries, and variable branches to the esophagus, mediastinum, and pericardium
  - major abdominal branches: lumbar and musculophrenic arteries, renal and middle suprarenal arteries, and visceral arteries (the celiac trunk, the superior mesenteric artery, and the inferior mesenteric artery)
in healthy adults, the aorta is usually less than 40 mm in diameter and gradually narrows downwards
- the aorta enlarges with age at a rate of about 0.9 mm every ten years in men and 0.7 mm every ten years in women

aortic atherosclerosis
inflammatory disorders (e.g., Takayasu’s arteritis)
aortic aneurysms and pseudoaneurysms (abdominal, thoracic, thoracoabdominal)
acute aortic syndromes (AAS)
- aortic dissection (DA) – type A and B
- intramural hematoma (IMH)
- penetrating aortic ulcer (PAU)
traumatic aortic injury
genetic syndromes (e.g., Marfan syndrome)
congenital defects (e.g., coarctation of the aorta)

aortic arch atherosclerosis is common in individuals aged over 60
there is an increased risk of thrombus formation, which may be the source (along with atheroma particles) of systemic or cerebral emboli
- spontaneous embolism (previously classified as cryptogenic stroke); the floating thrombus poses the highest risk
- during diagnostic procedures (e.g.,coronarography)
- during cardiac surgery with extracorporeal circulation requiring cannulation of the aorta
the advent of transesophageal echocardiography (and later CTA/MRA) allowed the detection of atherosclerotic plaques within the aortic arch

involvement of each aortic segment is associated with specific consequences and complications
- ascending aorta and arch: stroke, systemic embolization (distal arch)
- abdominal aorta: aneurysm formation, abdominal angina, PAD, etc.)
atheromatous plaques in the aortic arch are associated with an increased risk of cerebrovascular embolic events (→ complications during extracorporeal circulation)
- especially plaques ≥ 4 mm are associated with an increased risk of recurrent stroke
- extensive aortic arch atherosclerosis is also associated with an increased risk of “silent” white matter lesions [Tugcu, 2016]
assessment of the aortic arch may help identify individuals who may benefit from aggressive treatment of vascular risk factors
stroke caused by aortic arch atherosclerosis is usually classified as large artery atherosclerosis (CISS, TOAST 1) or cardio-aortic embolism (SSS-TOAST 2)

atherosclerosis is a complex systemic disease in which vascular risk factors play a critical role

clinical examination
- palpation and auscultation of the neck and abdomen to detect a noticeable pulsation or turbulent flow causing murmurs
- blood pressure measurement on both arms
laboratory examination – screening for cardiovascular risk factors

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complex and aggressive management of vascular risk factors is indicated (patients with aortic atherosclerosis belong to the very high-risk group)

stroke patients or asymptomatic patients with extensive aortic atherosclerosis should receive antiplatelet therapy unless anticoagulation is indicated for another reason (e.g., Afib) (AHA/ASA 2021 1/C-LD)
consider short-term anticoagulant treatment on a case-by-case basis in the presence of documented mobile thrombus

there are no data on the benefit of prophylactic aortic arch surgery or stenting to prevent stroke