Extract

A 48-year-old hypertensive male presented with acute chest pain radiating to the back. Initial computed tomography angiography (CTA) revealed a Stanford type A aortic dissection extending from the aortic root to the iliac arteries. Multiphasic functional cardiovascular reconstructions revealed a mobile intimomedial flap (see Supplementary data online, Video S1) and dynamic obstruction of the left main coronary artery (LMCA) ostium and proximal right coronary artery (RCA). Curved multiplanar reconstruction of the LMCA (Panel A) and RCA (Panel B) in systole shows anterograde flow in the true lumen (*). Furthermore, diastolic images depict LMCA (Panel C) and RCA (Panel D) ostial occlusion by the intimomedial flap (arrowhead). Additionally, the hypertensive false lumen extrinsically compresses the proximal third of the RCA (arrowhead in Panel D), favouring its near-occlusion. Cardiac injury markers were persistently elevated, in keeping with a myocardial malperfusion syndrome. The patient underwent a modified Bentall–De Bono procedure, and histological analysis of the excised aortic root wall confirmed separation of the ‘tunica intima’ and ‘tunica media’ (Panel E). Malperfusion syndrome arises from end-organ ischaemia caused by static, dynamic or mixed aortic branch obstruction, or ostial disconnection. Static obstruction involves a fixed intimomedial flap protrusion into an aortic branch, while dynamic obstruction may result from intermittent prolapse of the intimomedial flap over a vascular ostium, or pressure imbalance between a true hypotensive lumen and a false hypertensive lumen. This case underscores the critical role of multiphasic functional CTA with cinematic reconstructions throughout the cardiac cycle in identifying the dynamic behaviour of the intimomedial flap, diagnosing coronary obstruction, and differentiating its underlying mechanisms.

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