Middle aortic syndrome: distal thoracic and abdominal coarctation, a disorder with multiple etiologies.
Congenital coarctation of the thoracic aorta at the ligamentum arteriosum or the aortic arch is well recognized. But a much less common variety (0.5% to 2.0%) of aortic coarctation is located in the distal thoracic aorta, or abdominal aorta, or both and is often called "middle aortic syndrome" or "mid-aortic dysplastic syndrome." These types of aortic coarctation are most often secondary to a form of granulomatis vasculitis commonly known as Takayasu's disease in this country or aortitis syndrome in Japan. No single genesis explains every case and beside vasculitis as a cause, some are thought to be congenital in origin and others are associated with von Recklinghausen's disease. Eight patients with severe hypertension or claudication secondary to middle aortic coarctation were studied with aortograms and subsequently treated by vascular reconstruction procedures. Vascular reconstructions consisted of aortoaortic bypass, aortic resection with interposed grafting, reanastomotic resection of renal arteries into prosthetic grafts, and renal artery bypass with autogenous material. All eight patients' grafts have remained patent, with followups of 4 to 9 years, with relief of hypertension and claudication. Although Takayasu's disease can be progressive, aggressive surgical treatment in eight patients followed for 4 to 8 years postoperatively demonstrates that severe hypertension, claudication, or both are important indications for revascularization. Whatever the cause, assuming that active aortic inflammation has been medically treated and is in a burned-out state, patients with abdominal coarctation who have symptomatic renovascular hypertension, claudication, or both are good candidates for revascularization. Although surgical repair is more difficult than with congenital thoracic coarctation, because aortic walls are fibrotic and often also involve the renals, all eight of our patients had successful longterm correction of their hypertension and coarctation.