A case of congenital mid-aortic syndrome in pregnancy

Hypertension is a frequent medical complication in pregnancy associated with serious maternal and fetal morbidity and mortality. Secondary hypertension is present in 5–10% of cases and must be considered in the presence of drug resistance. Unrecognized causes of pre-existing hypertension occasionally becomes apparent only in pregnancy. A 30-year-old woman whose first pregnancy was complicated by an exacerbation of pre-existing mild hypertension demonstrated a persistently elevated blood pressure resistant to therapy in the puerperium. Investigations revealed a narrowed aorta with a left renal artery stenosis and a right duplex system with fibromuscular dysplasia of the upper right renal artery and a lower polar artery. She was given a diagnosis of congenital mid-aortic syndrome.

A left renal angioplasty was unsuccessful and a left nephrectomy was performed at 3 months post-partum with a main right renal artery angioplasty. Her blood pressure control improved initially but 10 weeks after her surgery she re-presented with renal angle pain and right renal artery stenosis was diagnosed on angiogram. A right angioplasty was unsuccessful and therefore after 4 months a prosthetic graft patch angioplasty of the aorta and a right aorta–renal bypass was performed. This was successful with resultant good perfusion to the remaining kidney and the blood pressure returned to normal. A year later, she was asymptomatic, taking aspirin 75 mg daily. She was normotensive (135/85 mm Hg) with normal renal function (creatinine 94 μmol l⁻¹; urea 4.7 mmol l⁻¹).