Long-segmental middle aortic coarctation: a rare case first diagnosed by transthoracic echocardiography

Middle aortic coarctation (MAC), also known as middle aortic syndrome, is an atypical aortic coarctation characterized by narrowing of the distal thoracic aorta and proximal abdominal aorta. MAC is a rare disease commonly diagnosed by computed tomography angiography (CTA). In this paper, we present a case of long-segmental MAC first diagnosed by transthoracic echocardiography (TTE) and further evaluated by CTA.

A 14-year-old girl, with dyspnea and fatigue on exertion for 2 months and refractory hypertension for 6 months, was referred by the local clinic to our hospital. Physical examination showed blood pressure up to 176/100 mmHg measured in the arms despite dual antihypertensives, a marked pressure gradient between her arms and legs, and weak pulses in both dorsal pedes arteries. TTE revealed a segmental narrowing in the descending thoracic aorta below the level of the atrioventricular sulcus, with a calcified plaque in the stenotic region. Abdominal vascular ultrasound revealed the segmental narrowing extending to the descending abdominal aorta (5.7 mm in diameter) above the level of the superior mesenteric artery. Subsequently, CTA verified a long-segment narrowing in the descending aorta from the level of T8 to L2 vertebra, with a calcified plaque in the stenotic aorta, right renal artery involvement, and a rich network of collateral vessels between the pre-and post-stenotic region. The patient was referred for cardiovascular surgery in which a successful ascending aorta-abdominal aorta bypass was performed.

Although MAC is usually diagnosed by CTA, it may also be first diagnosed by TTE in some patients whose longitudinal axis view of the thoracic descending aorta could be shown. Careful TTE scan can improve the diagnostic rate of MAC, especially for some hypertension patients whose marked pressure gradient between arms and legs was ignored by the physician.