Teaching Case

A 74-year-old former smoker, diabetic and hypertensive male patient presented to the emergency department with an acute onset of chest pain and diaphoresis. The patient was under chronic anticoagulant therapy (warfarin) due to atrial fibrillation and had a dilatated ascending aorta (with diameter of 4.3cm) documented on a recent echocardiography.

Non-contrast enhanced CT images revealed ascending aortic aneurysm, and a crescentic and hyperattenuating region of thickening of the thoracic aortic wall (Fig. 1). Inward displacement of aortic intimal calcifications was also present. On contrast enhanced CT, a contrast material-filled image was seen penetrating into the thickened wall of the ascending aorta (Fig. 2). The aortic intramural collection extended along the surface of the main and branch pulmonary arteries (Fig. 3), as well as along the walls of the aortic arch branch vessels (Figs. 2 and 4). Haemopericardium, bilateral pleural effusions and mediastinal haematoma were also seen (Figs. 1-4).

The findings were compatible with intramural haematoma (IMH) secondary to penetrating atherosclerotic ulcer (PAU) of the ascending aorta, complicated with ascending aorta aneurysm and rupture, with IMH extension to the pulmonary arteries and aortic arch branch vessels.

The patient had a sudden cardiac arrest and did not respond to advanced life support resuscitation manoeuvres.

Acute aortic syndrome (AAS) comprises a constellation of life-threatening aortic diseases, which includes aortic dissection, PAU and IMH.

IMH is a contained aortic wall haematoma without a demonstrable intimal flap. Several mechanisms have been proposed for the pathogenesis of IMH [1-5]. IMH may originate as a consequence of PAU [3-5]; in this case, an atheromatous plaque ulcers, erodes the intima and the internal elastic lamina, and ruptures into the media, resulting in intramedial haematoma formation [4].

PAU most commonly occurs in the descending thoracic aorta [1,7,8], being rare in the ascending aorta [6,9]. PAU in the ascending aorta with associated secondary IMH, as occurred in our patient, is very rare [3,5].

Typically, PAUs are seen in older male patients with a history of hypertension, smoking and coronary artery disease [6,8].

The clinical presentation of the AAS entities is nonspecific and often similar amongst them. Excruciating chest or back pain is the most common presenting symptom.

Imaging plays a vital role in AAS diagnosis. The goals of imaging in AAS are: to confirm the diagnosis; to identify the site, extension, and complications of the disease; to help in treatment planning. CT is the imaging modality of choice in the emergency setting.

On CT, PAU appears as a focal contrast material-filled, pouch-like protrusion of the aorta or a contrast-filled image penetrating into the thickened aortic wall, with an adjacent subintimal haematoma [1,6,9,10].

On unenhanced axial CT images, IMH typically appears as a crescentic or circular, eccentric, hyperattenuating region of thickening of the aortic wall [1,6,11]. Aortic intimal calcifications may be displaced inward [1,6]. On contrast-enhanced CT, the intramural fluid collection does not present contrast enhancement [1].

Possible complications of IMH include: aortic dissection; aortic aneurysm; pulmonary extension of IMH; extension of IMH along the walls of the coronary arteries; ulcer-like projections; aortic rupture, including rupture into the pericardial sac (with haemopericardium) and into the mediastinum (with mediastinal haematoma); haemorrhagic pleural effusion; acute aortic regurgitation; myocardial infarction [1,2,4,11-13].

PAUs located in the ascending aorta usually rupture and are commonly lethal [9]. Patients with IMH due to PAU seem to have a worse prognosis than patients with IMH without PAU [3]. When the IMH is associated with a PAU, urgent intervention should be considered [3].

Take Home Message / Teaching Points:

PAU in the ascending aorta with associated secondary IMH is rare and is associated with poor prognosis.

Written patient consent for this case was waived by the Editorial Board. Patient data may have been modified to ensure patient anonymity.