An infrarenal aortic occlusion in a young adult

A 27-year-old female patient came to the hospital complaining of intermittent dizziness and headaches, worsened by exertion and relieved by rest, over the past month. She reported coldness and weakness in her lower limbs since childhood. Physical examination revealed a blood pressure of 178/116 mm Hg and a decreased skin temperature along with lower blood pressure in both lower limbs. A CT angiography (CTA) was requested for a diagnostic work-up of the aorta to rule out a steno-occlusive disease.

CTA images showed an infrarenal aortic occlusion, located 52 mm above the aortic bifurcation, measuring 38 mm in length. The celiac artery (CA) and its branches, as well as both renal arteries (RA), were patent. The superior mesenteric artery (SMA) was enlarged, branching out the inferior mesenteric artery (IMA) and forming dilated, tortuous collaterals. One of these served as a feeding artery to the distal abdominal aorta, just below the occluded segment. The bilateral iliac arteries were normal.

Subsequently, the patient underwent bypass surgery using a combined approach of thoracoscopy and laparoscopy. The graft was anastomosed proximally to the mid-descending aorta (end-to-side) and distally to the collateral feeding artery (end-to- side). The temperature and the blood pressure of her lower limbs returned to normal after surgery. Her hypertension was controlled by pharmacotherapy. Follow-up CTA, performed at 8 days, 1 year and 2 years after surgery, showed patency of the anastomoses and the graft along with a reduction in the number of collaterals.

Fig. 2: cVRT images show an overview of the infrarenal aortic occlusion pre- and post-surgery. The bypass graft is patent and there are less collaterals.

An infrarenal aortic occlusion, also known as Leriche syndrome, refers to a complete occlusion of the aorta distal to the renal arteries. It is a rare condition in young women and can be caused by various etiologies such as arteriosclerosis, vasculitis and thrombosis. According to the Trans-Atlantic Inter-Society Consensus II (TASC II), it is a type D lesion, and surgery is the treatment of choice. [1] For pre-operative planning, CTA provides direct anatomical visualization of the location of the occlusion, the affected visceral arteries, the type and extent of collateralization and the level of the most proximal and distal arterial segments suitable for graft placement. Post-operatively, CTA is performed to evaluate the patency of the anastomoses and the graft, as well as the changes of the collaterals and the native arteries. When CTA is acquired using Dual Energy (DE), such as in this case, bony structures can be easily subtracted in an automated workflow, providing unobscured views of the vascularity. Three-dimensional demonstration can be facilitated using cinematic volume rendering technique (cVRT). Radiation dose reduction is achieved by applying advanced techniques such as CARE Dose4D (Real-time Anatomic Exposure Control) and ADMIRE (Advanced Modeled iterative Reconstruction). As shown in this case, a comprehensive pre- and post-operative DE CTA assessment of the infrarenal aortic occlusion is successfully achieved using only 40 mL of contrast agent, with a dose of 3.6 mGy, in 3.6 seconds.