CASE 7820 Published on 06.10.2009

Silent Emergency

Section

Cardiovascular

Case Type

Clinical Cases

Authors

Purvis JA, Hughes SM.

Patient

70 years, male

Clinical History
Stanford type A aortic dissection is a life-threatening condition with a high mortality usually associated with severe pain radiating into the back. About 5% of cases present coincidentally with no pain. We present a case with dissection on routine outpatient 64-multidetector coronary computed tomography for presumed ischaemic coronary pain.
Imaging Findings
A 70 year old man with intermittent jaw pain was referred for outpatient 64-slice coronary CT angiogram after equivocal dobutamine stress echo. Risk factors included hypertension, heavy smoking and hyperlipidaemia. During dobutamine stress echo, it was noted that the proximal ascending aorta was dilated and a scan of both aorta and coronaries was requested.
The patient arrived with no complaints and was prepared in the usual way. To reduce heart rate, he received 5mg of intravenous metoprolol via an antecubital vein and 400mcg of glyceryl trinitrate sublingually. Despite intravenous beta-blockade, his heart rate remained >64 bpm so a retrospectively ECG gated scan was performed.
The scan showed the presence of a saccular Stanford type A aortic dissection, with a 4 cm tear in the anteromedial aspect of the aorta (Fig 1). This extended upwards into the origin of the brachiocephalic trunk (Fig 2,3) and downwards to just above the origin of the right coronary artery. Thrombus could be seen within the inferior aspect of the dissection sac overlying the right coronary artery but the vessel itself was not compromised (Fig 4). The aortic valve was intact and left coronary system not involved (Fig 5). A little non-obstructive calcific plaque was seen in the coronary vessels but there was no intrusive plaque.
To his surprise, the patient was admitted directly from the CT room. Examination was negative with no inequality of pulses or neurological signs. Blood pressure was kept low with beta-blockade. He proceeded to urgent surgical repair.
Discussion
Thoracic aortic dissection is a life-threatening condition with mortality of up to 50% within the first twenty-four hours. Elderly, male, hypertensive patients are most at risk. Typical presentation is with severe chest pain radiating through into the back but involvement of the aortic valve, coronaries or aortic side-branches can produce protean symptoms. It is estimated that 20% of cases present with collapse due to tamponade, severe hypotension or carotid obstruction.

Our patient was stable on arrival for his investigation but his “chest pain radiating up into the jaw” over the last few months probably represented aortic pain rather than ischaemic heart disease.

Asymptomatic cases or cases with trivial discomfort are rare but are thought to represent about 5% of patients [1]. The condition is divided into acute presentation (< 14 days since onset) and chronic (>14 days) but treatment is the same for all Type A dissections – pain and blood pressure control are instituted until definitive surgical management.

Our patient denied any episodes of discomfort for several weeks. The presence of organised thrombus in the inferior aspect of the dissection sac suggests a degree of chronicity but it is difficult to time the event.

Coronary CT angiography provides one significant advantage over standard CT aorta and Magnetic Resonance: the ability to simultaneously image the coronary arteries and thus avoid a potentially hazardous catheter angiogram with risk of penetration or extension of the aneurysmal sac.

In conclusion, thoracic aortic dissection can present during routine cardiac imaging with no concomitant symptoms. Physicians should be aware of aortic pathology as a cause of milder, intermittent chest pain in high risk populations.
Differential Diagnosis List
Asymptomatic Stanford type A aortic dissection
Final Diagnosis
Asymptomatic Stanford type A aortic dissection
Case information
URL: https://www.eurorad.org/case/7820
DOI: 10.1594/EURORAD/CASE.7820
ISSN: 1563-4086