“Elephant Trunk” Mimicking Thoracic Aortic Dissection
The Role of Intravascular Ultrasound
A 68-year-old woman, with a history of hypertension and extensive aortic aneurysm associated with severe aortic valvular regurgitation, underwent aortic valve and ascending aorta replacement (Prisma Plus Stentless, 23 mm, Model 2500P, Edwards Life Sciences, Horw, Switzerland) and separate graft replacement of the aortic arch (vascular prosthesis, 8 mm, Gelweave Vascutek, Inchinnan, Scotland, UK) with the “elephant trunk” technique (Gelweave Vascuteck vascular prothesis, 24 mm).
Five months later, she was admitted to our emergency room because of stenocardia and severe upper abdominal pain with dizziness. A contrast-enhanced computed tomography scan showed a suspicious image of a membrane-like structure resembling a dissection flap in the anterolateral aspect of the descending thoracic aorta (Figure, A) close to the distal free end of the elephant trunk. The descending thoracic and abdominal aortas were of normal diameter, with no signs of dissection at any level.
The patient was referred to our institution for angiography to further explore the diagnosis of aortic dissection. Thoracic aortogram was not conclusive, revealing a mimicking localized intimal tear parallel to the aortic wall, without a mobile intimal flap (Figure, B). To further characterize these findings, an intravascular ultrasound examination was performed, using a 9-French, 9-MHz, Ultra ICE catheter (EP Technologies, Boston Scientific Corp, San Jose, Calif). During a manual pullback from the level of the left subclavian artery origin to the diaphragmatic hiatus, the inner aortic lumen and wall were examined. The equivocal computed tomography and angiographic images close to the distal free end of the elephant trunk were reinterpreted as an incomplete, asymmetric expansion of the vascular prosthesis, with enhanced blood within the graft lumen and outside the graft wall but within the lumen of the native aorta (Figure, C). Secondary elephant trunk fixation by endovascular stent grafting (Valiant Thoracic Stent Graft 32×150, Medtronic Vascular, Santa Rosa, Calif) was performed under fluoroscopic guidance (Figure, D); this was followed by a repeated intravascular ultrasound examination, which showed complete expansion of the skeletonized elephant trunk on the aortic wall (Figure, E). No neurological deficit occurred, and follow-up computed tomography scan confirmed the absence of endoleaks (Figure, F).
Familiarity with these images, coupled with detailed knowledge of surgical technique, is essential for accurately evaluating postoperative findings and avoiding misdiagnosis.