Penetrating atherosclerotic ulcer

A penetrating atherosclerotic ulcers (PAU) is a pathology that involves the aortic wall. This alongside an aortic dissection and a aortic intramural haematoma, is one of the possible causes of an acute aortic syndrome. 

Epidemiology

Typically, penetrating atherosclerotic ulcers are seen in older male patients with history of hypertension (up to 92%), smoking (up to 77%) and coronary artery disease (up to 46%) as well as chronic obstructive pulmonary disease (24-68%)¹.

Penetrating atherosclerotic ulcers account for 2.3 and 11% of all cases of acute aortic syndrome ¹. In approxiamtely 42-61% of cases there are concurrent aortic aneurysms, most often in the abdomen¹.

Clinical presentation

Typically patients present with symptoms of an acute aortic syndrome, namely acute intense chest pain, often described as tearing, ripping, migrating or pulsating ^1,8.

Some of the patients with penetrating atherosclerotic ulcer are asymptomatic and the diagnosis is made incidentally. In the previously cited article they cite the Mayo clinic series ² in which just 75% of the patients had been symptomatic.

Pathology

The term "penetrating atherosclerotic ulcer" describes an ulcerating atherosclerotic lesion that penetrates the intima and progresses into the media. In the early stages the lesions just ulcerate the intima and are often asymptomatic. With further progression they ulcerate the media and lead to a hematoma of variable size within the media ³.

The penetrating atherosclerotic ulcer can resolve completly or stay stable, but they can also lead to aortic dissection, aortic saccular aneurysms and even spontaneous aortic rupture. There are conflicting reports about the most common course of the penetrating atherosclerotic ulcer ¹.

Location

There is a greater predilection to involve the mid to distal thoracic aorta ⁶.

Radiographic features

CT

On CT-angiography of the aorta the typical finding is a contrast-filled, pouch-like protrusion of the aorta or into the thickened aortic wall in absence of a intimal flap or a false lumen. Often there are signs of extensive atherosclerosis in other sites apart from the ulceration ⁴.

Usually the ulcer is found in the descending part of the thoracic aorta. Ulcers of the aortic arch are less common, and rare in the ascending aorta ⁴.

Although associated pleural effusion correlates with clinical instability there are no validated imaging features for prediction of the course¹.

In follow-up studies increasing maximum diameter and depth of the ulcer is an obvious sign of progression¹.

Transesophageal echocardiogaphy

• usually TEE demonstrates a localized, craterlike protrusion of the aortic lumen into the thickened aortic wall ⁹.
• often there are signs of extensive atherosclerosis in other sites apart from the ulceration ⁹.

MRI and MRA

• T1-weighted SE sequences show a hyperintense hematoma in acut or subacute disease and can distinguish between hematoma and atherosclerotic plaque ⁹.
• furthermore similar findings to CTA ⁹.

DSA - angiography

• the typical finding is a contrast-filled, pouch-like protrusion of the aortic lumen ⁹.
• mostly several oblique projections are required ⁹. 

Complications

Recognised complcations include

• transmural aortic rupture
• embolic phenomena
• pseudo-aneurysm formation
• progressive aneurysmal dilatation

Treatment and prognosis

Although the involvement of the ascending aorta in penetrating atherosclerotic ulcers is rare, the ulcers usually rupture. Therefore early-urgent or emergent surgical intervention is recommended ⁴.

Ulcers of the descending aorta may initially be managed with an aggressive (antihypertensive) medical therapy in combination with close clinical and radiographic follow-up. If there are signs of progression, surgical or endovascular stent-grafting becomes necessary ⁴.

Differential diagnosis

General imaging differential considerations include

• aortic intramural haematoma
• aortic dissection
• saccular aneurysm
• (thoracic) aortic injury