A rare pattern of acute type A aortic dissection: complete circumferential intimal invagination into the proximal descending aorta

Introduction: A 59-year-old patient with acute chest pain, dyspnea and paresthesis of the left upper extremity presented to our emergency room. Initial computed tomography showed a seemingly normal ascending aorta, however, further downstream, an unusual, circumferential aortic dissection with complete invagination of the intima into the descending aorta causing a significant stenosis and an occlusion of the left subclavian artery was discovered and the patient was immediately taken to the OR. Intraoperatively, the intimal downstream invagination into the descending aorta was verified and resected, while the ascending aorta and part of the aortic arch were replaced (Borst II). An aorto-carotid-bypass was tailored and the aortic valve reconstructed. The patient was discharged seven days after.

Aims: Acute aortic dissection type-A (AADA) is a life-threatening condition associated with significant morbidity and mortality. Unlike the common AADA our patient presented with a rare pattern of dissection with a proximal entry tear in the aortic root and complete circumferential intimal dehiscence throughout the tubular ascending aorta and the aortic arch with downstream invagination of the intimal flap into the descending aorta. Preoperative computed tomography failed to identify a classic dissection membrane in the ascending aorta, neither did it reveal the entry tear or any intramural hematoma causing confusion and delay in reaching the correct diagnosis as a consequence.

Discussion: In acute dissection with circumferential invagination of the entirely dehiscent intima, classic stigmata – like an 'entry tear', the 'dissection membrane' or the 'false lumen' – might be absent, and, in particular with cross-sectional imaging alone, the diagnosis might be missed. Adequate imaging is necessary to depict the extent of the dissection in order to precisely plan the appropriate operative approach. Downstream imaging may become particularly vital in patients with rare pattern of aortic dissection who present with the classic symptoms of acute type A dissection lacking the classic radiological signs in the ascending aorta.