Lower Limb Ischemia as Acute Onset of Primary Aortic Occlusion: CTA Imaging and Management

Primary aortic occlusion (PAO) is defined as acute occlusion in the absence of aortic atherosclerosis or aneurysm. PAO is a rare disease with acute onset and can determine massive parenchymal ischemia and distal arterial embolization. The aim of our study was to focus on the assessment of clinical characteristic, CT signs, medical and surgical treatment, complication rates and the overall survival of PAO.

We retrospectively analyzed the data of all patients with acute lower limb ischemia and a final surgical or discharge diagnosis of PAO who underwent aortic CT angiography in ER settings in our hospital from January 2019 to November 2022.

A total of 11 patients (8 males/3 females; male/female ratio, 2.66:1, age range 49 to 79 years-old, mean age 65.27 y/o) with acute onset of lower limb impotence or ischemia were diagnosed with PAO. The etiology was thrombosis in all patients. The aortic occlusion was always located in the abdominal aorta and extended bilaterally through the common iliac arteries. The upper limit of the thrombosis was detected in the aortic subrenal tract in 81.8% of the cases, and in the infrarenal tract in 18.2%. A total of 81.8% of the patients were referred to the ER for symptoms related to lower limb: bilateral acute pain, hypothermia and sudden onset of functional impotence. Two patients (18.2%) died before undergoing surgery for multi-organ failure determined by the severe acute ischemia. The other patients (81.8%) underwent surgical treatment that included aortoiliac embolectomy (54.5%), aortoiliac embolectomy + aorto-femoral bypass (18.2%) and aortoiliac embolectomy and right lower limb amputation (9.1%). The overall mortality was 36.4% while the estimated survival at 1 year was 63.6%.

PAO is a rare entity with high morbidity and mortality rates if not recognized and treated promptly. Acute onset of lower limb impotence is the most common clinical presentation of PAO. Aortic CT angiography is the first-choice imaging technique for the early diagnosis of this disease and for the surgical treatment, planning and assessment of any complications. Combined with surgical treatment, anticoagulation is considered the first-line medical therapy at the time of diagnosis, during surgical treatment and after at discharge.