Presentation
Presyncopal attack and palpitations.
Patient Data
An Intimal flap involves the aortic root until the proximal aortic arch, proximal to the brachiocephalic trunk. The right main coronary artery arises from the smaller lumen while the left one arises from the larger lumen. No aneurysmal dilatation or thrombus was seen. No filling defects within the pulmonary trunk, bilateral main and segmental pulmonary arteries.
CT angiogram of the thorax showing normal opacification of the entire thoracic aorta and suprarenal abdominal aorta. The previously seen intimal flap is no longer visualized. No aneurysmal dilatation or filling defects.
In summary: Normal thoracic and suprarenal abdominal aorta with no evidence of aortic dissection
Case Discussion
This patient, who was 37 weeks pregnant, presented to the emergency department with pre-syncopal attack and palpitations. The ECG showed sinus tachycardia with S1 QIII TIII pattern. CTPA was performed to exclude pulmonary embolism. Instead, an intimal flap was observed involving the ascending aorta, leading to the diagnosis of Stanford Type A aortic dissection.
A multidisciplinary team, including Cardiothoracic Surgery, Obstetrics and Cardiac Anesthesiology, was alerted for a potential combined Cesarean section and aortic dissection repair surgery. A CT angiogram was arranged to confirm the extension of the dissection. However, there was normal opacification of the aorta with absence of the previously seen intimal flap, suggesting that the earlier CTPA was actually a false positive ie. aortic pseudo-dissection. Patient safely delivered via emergency Cesarean section due to foetal distress the following day.
Aortic pseudo-dissection is thought to be caused by cyclical movements of the aortic root resulting in
motion artifacts which could convincingly mimic an intimal flap. Such scenarios may be encountered during emergency CTPA performed to exclude pulmonary embolism when contrast has already opacified the thoracic aorta. This case underscores the importance of conducting a proper CT angiogram in such situations, preferably ECG-gated, to avoid misdiagnosing an aortic pseudo-dissection and subjecting the patient to unnecessary surgery which carries high morbidity and mortality risk.
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