Coarctation of the Abdominal Aorta Unmasked in Pregnancy: A Rare Vascular Cause of Severe Refractory Hypertension with Bilateral Lower-Limb Pulse Deficit.

Abstract

Background:                                                                                                                                                                                                                  Abdominal aortic coarctation, also termed midaortic syndrome, is an uncommon cause of secondary hypertension and accounts for a small proportion of aortic coarctation cases. Its diagnosis is frequently delayed because severe hypertension in young adults may be attributed to more common hypertensive disorders. Pregnancy can unmask or worsen the condition because increased blood volume and cardiac output impose additional haemodynamic stress across the fixed obstruction.

Case Report:
A 27-year-old primigravida with chronic hypertension and dilated cardiomyopathy presented at 29 weeks of gestation with progressive exertional dyspnoea and palpitations. Despite treatment with labetalol and methyldopa, her blood pressure remained poorly controlled at 170/100 mmHg. Examination revealed tachycardia, elevated jugular venous pressure, bilateral pedal oedema, an epigastric systolic bruit, and complete absence of bilateral femoral, popliteal, and dorsalis pedis pulses. Echocardiography demonstrated dilated left-sided chambers, global left ventricular hypokinesia, moderate mitral regurgitation, pulmonary hypertension, and a left ventricular ejection fraction of 30%. Computed tomography angiography showed a 2.9-cm focal narrowing of the abdominal aorta immediately distal to the superior mesenteric artery, with a minimum lumen of 7 × 6 mm. A small right kidney and possible renal artery involvement, together with elevated plasma renin activity, suggested an additional renovascular mechanism. Multidisciplinary management included intravenous labetalol, oral nifedipine, and deferral of definitive vascular intervention until after delivery. Worsening maternal cardiac status necessitated caesarean delivery at 34 weeks, resulting in a 1.9-kg growth-restricted female neonate with favourable APGAR scores.
Conclusion:                                                                                                                                                                                                                Abdominal aortic coarctation should be considered in young pregnant women with refractory hypertension, absent lower-limb pulses, abdominal bruit, or cardiac dysfunction. Careful pulse examination and timely vascular imaging are essential for diagnosis. Multidisciplinary management, cautious blood-pressure control, planned delivery, and postpartum vascular repair may reduce maternal and fetal complications.