CASE 15843 Published on 15.08.2018

Teaching Case

Section

Cardiovascular

Case Type

Clinical Cases

Authors

Dr Shoba Ratnagobal MBBS, Dr Vini Carraro Do Nascimento MD, Dr Edward Wang MBBS, Mr Christopher Merry MBBS FRACS LLM, Dr Yuranga Weerakkody MBChB FRANZCR

Royal Perth Hospital; Wellington Street 6000 Perth, Australia; E-mail: shoba.ratnagobal@health.wa.gov.au

Patient

75 years, male

Categories

Area of Interest Cardiovascular system, Arteries / Aorta ; Imaging Technique CT, CT-Angiography, Percutaneous ;

Procedure Education, Imaging sequences, Surgery ; Special Focus Pathology, Acute ;

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Clinical History

A 75-year-old male patient presented with acute severe upper right-sided chest pain radiating to the neck with associated diaphoresis on a background of hypertension. The pain had come on at rest and was persistent. He was evaluated with chest radiograph and multi-phase ECG-gated CT of the thoracic aorta.

Differential Diagnosis List

Spontaneous acute aortic intramural haematoma with penetrating aortic ulcer.

Periaortic fluid collection

Aortic intramural haematoma without penetrating aortic ulcer

Imaging Findings

The initial chest radiograph (not shown) was normal in appearance.

The subsequent non-contrast CT demonstrated a crescentic area of increased attenuation at the aortic root and into the ascending aorta (Fig 1), extending superiorly to the level of the right brachiocephalic artery bifurcation.

On the arterial phase CT images a subtle outpouching at the anteromedial aspect of the aortic root (Fig 2) was noted. No intimal flap was identified. There was a moderate pericardial effusion, with attenuation of 39HU (Fig 3d).

Intra-operatively a haemopericardium was present. The aorta was dilated with a purple discolouration. Incision of the ascending aorta revealed intramural haematoma with a penetrating aortic ulcer (Fig 4), correlating to the site of subtle outpouching noted on CT.

Discussion

Acute Aortic Syndrome (AAS) is classified into six categories (classic aortic dissection, intramural haematoma (IMH), limited intimal tear, penetrating atherosclerotic ulcer, iatrogenic dissection and rupturing thoracic aortic aneurysm) as per the American College of Cardiology Foundation/American Heart Association classification [1,2]. IMH accounts for approximately 7% of all AAS [3].

Clinical presentations of AAS are similar, with acute onset of severe chest or back pain[4] associated with hypertension [5]. Those with IMH in particular are usually elderly patients [2].

Early recognition of AAS is paramount due to risk of rupture if treatment is delayed. Risk of rupture is significantly higher with IMH (26%) and PAU (40%) compared with classic aortic dissection (8%) [4]. The presence of IMH also increases the risk of dissection [6]. Unenhanced and enhanced CT act as diagnostic and risk stratification tools [7].

IMH implies an intact intimal layer, unlike the intimal flap of aortic dissection, with underlying pathology of ruptured vasa vasorum [8,9]. There are reports of IMH where small intimomedial tears are not seen on imaging but are visible intraoperatively, suggesting tears may be more significant than vasa vasorum rupture [2]. PAU has been less commonly implied as a cause of IMH [6,8].

Limited intimal tears are the least common AAS, caused by an intimal tear with no subsequent dissection of blood into the media [1], in contrast with IMH. On CT these appear as a partial thickness tear of the luminal aortic wall, however are subtle and easily missed [1].

In AAS, chest radiographs can be normal or demonstrate a widened mediastinum. Multi-phase CT is the initial study for differentiation of AAS in our institution. A non-contrast study is performed to demonstrate a hyperattenuating crescent, followed by an arterial phase study to assess aortic wall contour. If irregular this suggests ulceration or intimal flap.

IMH are classed as per the Stanford classification of Type A or B [10]. Surgical management is indicated for Type A IMH [6] due to very high frequency of complications [11]. In contrast, type B distal IMH can be managed conservatively and usually resolves without further intervention [11].

In IMH with PAU of the ascending aorta, the rupture rate is 26-40%, mandating emergent surgical management and replacement of the diseased aortic segments [12]. Close follow-up with imaging is suggested, particularly of those treated conservatively [13].

Take home message: This case highlights the importance of unenhanced CT in those with AAS, especially if a large PAU or intimal flap is not present.

Written informed patient consent for publication has been obtained.

References

[1] Chin AS, Willemink MJ, Kino A, Hinostroza V, Sailer AM, Fischbein MP, Mitchell RS, Berry GH, Miller DC, Fleischmann D (2018) Acute Limited Intimal Tears of the Thoracic Aorta. J Am Coll Cardiol 71(24): 2273-2785 (PMID: 29903350)

[2] Gutschow SE, Walker CM, Martinez-Jimenez S, Rosado-de-Christenson ML, Stowell J, Kunin, JR (2016) Emerging Concepts in Intramural Hematoma Imaging. Radiographics 36: 660-674 (PMID: 27163587)

[3] Evangelista A, Isselbacher EM, Bossone E, Gleason TG, Eusanio MD, Sechtem U, Ehrlich MP, Trimarchi S, Braverman AC, Myrmel T, Harris KM, Hutchinson S, O’Gara P, Suzuki T, Nienaber CA, Eagle KA, IRAD Investigators (2018) Insights From the International Registry of Acute Aortic Dissection: A 20-Year Experience of Collaborative Clinical Research. Circulation 137(17): 1846-1869 (PMID: 29685932)

[4] Corvera, JS (2016) Acute aortic syndrome. Ann Cardiothorac Surg 5(3): 188-193 (PMID: 27386405)

[5] Vilacosta I, San Román JA (2001) Acute aortic syndrome. Heart 85(4): 365-368 (PMID: 11250953)

[6] Baikoussis NG, Apostolakis EE, Siminelakis SN, Papadopoulos GS, Goudevenos J (2009) Intramural haematoma of the thoracic aorta: who's to be alerted the cardiologist or the cardiac surgeon?. J Cardiothorac Surg 4: 54 (PMID: 19793400)

[7] Liu YH, Ke HY, Lin YC, Tsai CS (2016) A penetrating atherosclerotic ulcer rupture in the ascending aorta with hemopericardium: a case report. J Cardiothorac Surg 11: 103 (PMID: 27400685)

[8] Wann S, Jaff M, Dorros G, Sampson C (1996) Intramural hematoma of the aorta caused by a penetrating atheromatous ulcer. Cardiol Clin 19(5): 438-439 (PMID: 8723608)

[9] Song J (2004) Diagnosis of aortic intramural haematoma. Heart 90: 368-371 (PMID: 15020502)

[10] Daily P, Trueblood H, Stinson E, Wuerflein R, Shumway N (1970) Management of acute aortic dissections. Ann Thorac Surg 10(3): 237-247 (PMID: 5458238)

[11] Nienaber CA, von Kodolitsch Y, Petersen B, Loose R, Helmchen U, Haverich A, Spielmann RP (1995) Intramural hemorrhage of the thoracic aorta. Diagnostic and therapeutic implications. Circulation 92(6): 1465-1472 (PMID: 7664428)

[12] Lansman SL, Saunders PC, Malekan R, Spielvogel D (2010) Acute aortic syndrome. J Thorac Cardiovasc Surg 140: 92-97 (PMID: 21092805)

[13] Abbas, A, Brown, IW, Peebles, CR, Harden, SP, Shambrook, JS (2014) The role of multidetector-row CT in the diagnosis, classification and management of acute aortic syndrome. Br J Radiol 87(1042): 20140354 (PMID: 25083552)

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