4D Flow Cardiovascular Magnetic Resonance Uncovers the Hemodynamic Clue in Aortic Dissection

Persistent or recurrent aortic coarctation after surgical repair can create hemodynamic stress that predisposes to aneurysm formation and dissection.

A 58-year-old man with prior extra-anatomic bypass repair of coarctation presented with acute interscapular pain and an upper-to-lower limb pressure gradient of >40 mm Hg. Computed tomography showed a thrombosed graft, a descending thoracic aortic aneurysm, and a Stanford type B dissection. Multimodal imaging, including 4D flow cardiovascular magnetic resonance, showed a high-velocity jet traversing the coarctation and striking the descending thoracic aorta where aneurysmal enlargement, focal wall shear stress (WSS) elevation, and the intimal tear colocalized. Hybrid repair with a frozen elephant trunk and thoracic endovascular aortic repair was performed; a subsequent type II endoleak was successfully treated by coil embolization.

This case highlights flow-mediated mechanisms of aneurysm expansion and dissection, and suggests that parameters such as WSS may serve as adjunctive tools to predict complications in selected patients.

In adults with repaired aortic coarctation, persistent or resistant hypertension should prompt evaluation for recurrent obstruction. 4D flow cardiovascular magnetic resonance can quantify WSS and abnormal flow patterns, offering mechanistic insight and potential value for risk stratification in complex aortic disease.