CASE 7265 Published on 05.02.2009

Two forms of acute aortic syndromes in the same patient

Section

Cardiovascular

Case Type

Clinical Cases

Authors

Seco M, Cavalheiro F, Marques P, Curvo-Semedo L.

Patient

75 years, male

Clinical History
A 75 year old male, with longstanding arterial hypertension, came to our emergency department with acute chest pain.
Imaging Findings
The patient came to our institution with acute onset of chest pain (4 hours of evolution). He was a known longstanding hypertensive patient. Physical examination, besides demonstrating arterial hypertesnion (170/100), was normal. ECG and cardiac enzymes were also normal, with no signs of cardiac ischemia. Chest radiography had no relevant alterations.
As the pain persisted, even with analgesics, a chest CT was requested. Non-contrast images showed (Fig 1), at ascending aorta, a crescive area of wall thickening that was spontaneously dense compared to the vascular lumen associated with displacement of intimal calcifications. After intravenous contrast administration (Fig 2) there was no aortic wall enhancement and the interface with the enhanced lumen was smooth and regular. Beginning in the proximal descending aorta, just after the origin of the left subclavian artery, two lumens were seen (true and false) separated by an intimal flap (Fig 3,4). These findings were in relation with acute intramural haematoma (type A) complicated by aortic dissection (type B).
Discussion
Intramural haematoma (IMH) accounts for 10-30% of patients presenting with acute aortic syndromes (spectrum of aortic emergencies that also include aortic dissection, penetrating atherosclerotic ulcer of the aorta and aortic aneurysm leak and rupture). Aortic intramural haematoma may occur as a primary event in hypertensive patients in whom there is spontaneous bleeding from vasa vasorum into the media or may be caused by a penetrating atherosclerotic ulcer.
Intramural haematoma is thought to begin with the rupture of the vasa vasorum, the blood vessels that penetrate the outer half of the aortic media to supply the aorta wall [1]. The haematoma propagates along the media layer of the aorta [2]. Consequently, intramural haematoma weakens the aorta and may progress either to outward rupture of the aortic wall or to inward disruption of the intima, the latter leading to communicating aortic dissection (like our patient that also had aortic dissection of the proximal descending aorta) [3].
On CT, IMH manifests as a crescive, or circular, area of aortic wall thickening that is spontaneously dense when compared to the vascular lumen on non-contrast-enhanced images. Intramural haematoma can be distinguished from mural thrombus by identification of the intima: mural thrombus lies on top of the intima, which is frequently calcified, whereas intramural hematoma is subintimal [4]. Another useful finding is that IMH, unlike atherosclerotic plaques, creates a smooth interface with the enhanced lumen.
Stanford classification of aortic dissections also applies to IMH: IMH is type A when there is involvement of the ascending aorta (regardless of the distal extent) and it is type B when there is no involvement of the ascending aorta. This classification is important because in most US and European centres, acute type A IMH is managed surgically due to the same risks of classic aortic dissection.
Differential Diagnosis List
Intramural hematoma of aorta (type A) complicated by aortic dissection.
Final Diagnosis
Intramural hematoma of aorta (type A) complicated by aortic dissection.
Case information
URL: https://eurorad.org/case/7265
DOI: 10.1594/EURORAD/CASE.7265
ISSN: 1563-4086