Aortic dissection in a pregnant woman is a rare event that carries an increased risk of maternofetal morbidity and mortality, with a risk of maternal death in the first month from presentation of over 80%. The estimated incidence of aortic dissection in the UK is around 1 per 100,000 maternities. In pregnancy, aortic dissection is more commonly associated with connective tissue disorders, particularly Marfan’s syndrome and others such as Turner’s, Ehlers-Danlos type IV and related syndromes. Other risk factors include structural disease such as coarctation of the aorta and bicuspid aortic valve, inflammatory vasculitides, chronic hypertension and cocaine abuse.
Approximately half of the acute dissections in women under 40 years old occur during pregnancy or after delivery. The increased risk of dissection in the obstetric population is attributed to pregnancy-induced haemodynamic stress caused by volume overload and increased downstream resistance secondary to compression by the gravid uterus. In addition, hormonal effects may alter the structural elements of the aortic wall. The haemodynamic changes become more marked in the last trimester of pregnancy and the immediate postpartum period, when the risk of dissection peaks. Stanford type A aortic dissection (DeBakey types I and II) involves the ascending aorta and is the more common type in pregnancy. Stanford type B (DeBakey type III) does not involve the ascending aorta.
Problems and special considerations
The initial presentation may include a myriad of clinical symptoms that overlap with other conditions and can cause a diagnostic dilemma. Early diagnosis is crucial, as mortality increases by 1% per hour for the first 48 hours after presentation.
Acute dissection typically presents with severe chest or interscapular pain of abrupt onset that is described as tearing, stabbing or sharp and may radiate to the jaw, arm or epigastrium. The pain may be migratory in nature and may manifest in the abdomen or legs with type B dissections. Other associated features may include systolic hypertension, tachycardia, dyspnoea, syncope or neurological symptoms. Pulse deficits, asymmetric blood pressure or focal neurology may be elicited on examination. Cardiac auscultation may reveal a diastolic murmur of acute aortic regurgitation. Cardiovascular decompensation may indicate heart failure, myocardial infarction, aortic rupture or cardiac tamponade.
Women who present with severe unexplained pain requiring opioid analgesia must be reviewed by a senior clinician and be fully investigated. Electrocardiography may reveal ST segment changes, and a plain chest x-ray may show a widened mediastinum, but both tests may be normal or inconclusive. Imaging must be expedited, and transthoracic echocardiography is recommended as an initial investigation. Magnetic resonance imaging, computerised tomography and transoesophageal echocardiography have comparable accuracy in confirming or ruling out the diagnosis of aortic dissection, but the latter two may be more appropriate in the haemodynamically compromised patient.
Management
Pre-pregnancy counselling and inter-specialty management is essential in women with known aortic disease. Prophylactic surgical repair may be considered in some patients. Pregnant women with a dilated aortic root should have adequate blood pressure control and regular echocardiographic monitoring. Women with a history of aortic dissection should be delivered in a hospital equipped with facilities for cardiothoracic surgery.
Conservative management may be appropriate in small uncomplicated type B dissection, with strict blood pressure control and close surveillance. Other cases may require open surgery (with or without caesarean section depending on gestational age and severity) or endovascular repair. Anaesthesia for aortic root repair is as for cardiac surgery of any kind in pregnancy, taking particular care to avoid hypertension.
Key points
• Aortic dissection is an uncommon disease that carries an over 80% risk of death in the first month from presentation.
• Pregnant women presenting with abrupt-onset severe chest or back pain must be thoroughly investigated.
• Timely diagnosis allows the initiation of life-saving treatment and an improved chance of survival.
Further reading
Erbel R, Aboyans V, Boileau C, et al.; ESC Committee for Practice Guidelines. 2014 ESC Guidelines on the diagnosis and treatment of aortic diseases: Document covering acute and chronic aortic diseases of the thoracic and abdominal aorta of the adult. The Task Force for the Diagnosis and Treatment of Aortic Diseases of the European Society of Cardiology (ESC). Eur Heart J 2014; 35: 2873-926.
European Society of Cardiology. ESC guidelines on the management of cardiovascular diseases during pregnancy: the Task Force on the Management of Cardiovascular Diseases during Pregnancy of the European Society of Cardiology (ESC). Eur Heart J 2011; 32: 3147-97.
Rajagopalan S, Nwazota N, Chandrasekhar S. Outcomes in pregnant women with acute aortic dissections: a review of the literature from 2003 to 2013. Int J Obs Anes 2014; 23: 348-56.
Smok D. Aortopathy in pregnancy. Semin Perinatal 2014; 38: 295-303.