Spontaneous coronary artery dissection is a rare cause of myocardial ischaemia or sudden death, predominantly affecting young women with no known risk factors for cardiovascular disease. The case described emphasises the benefit of early diagnosis and the need to individualise management based on patient response to treatment.
- LAD, left anterior descending
- Coronary artery
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Spontaneous coronary artery dissection is a rare cause of myocardial ischaemia or sudden death. Despite first being described as long ago as 1931, by Pretty,1 the diagnosis is often delayed or missed. This condition predominantly affects young women with no known risk factors for cardiovascular disease. We describe a case that emphasises the benefit of early diagnosis and the need to individualise management based on patient response to treatment.
A 43 year old woman presented to the accident and emergency department of a regional university hospital following two episodes of retrosternal chest pain each lasting 10 minutes. She had no known risk factors for ischaemic heart disease. Her last pregnancy was 2 years previously. ECG on admission was normal but subsequently demonstrated T wave inversion in the anterior leads. Troponin levels were elevated. Coronary angiography was performed and revealed a 75% narrowing of the mid left anterior descending (LAD) artery due to a dissection (fig 1). Left ventricular ejection systolic fraction was 50%.
The patient was initially managed medically but continued to experience chest pain. Repeat coronary angiography revealed further extension of the dissection with total occlusion of the mid LAD artery and moderate apical dyskinesia. She was referred for surgical management and underwent emergency double coronary artery bypass with a left internal mammary artery graft to the LAD and a reversed saphenous vein graft to her first diagonal. Her post-operative recovery was unremarkable and she was discharged home 10 days later. She was asymptomatic at the time of her 6 month review.
Spontaneous coronary artery dissection has been defined as the presence of a haematoma within the media of the coronary artery that impinges upon the lumen of the artery.2 Secondary causes of coronary artery dissection must be excluded before a coronary artery dissection is deemed spontaneous. These secondary causes include cardiac catheterisation,3 chest trauma,4 extension of an aortic dissection,5 and cardiac surgery. The majority (80%) of cases of spontaneous coronary artery dissection occur in women, with one third occurring in the third trimester of pregnancy or within the first 3 months postpartum.6 The LAD is affected in 80% of cases,7 which may explain the high mortality rates. There is a clinical spectrum from stable to unstable angina, myocardial infarction, cardiogenic shock, and sudden death.
The aetiology of spontaneous coronary artery dissection is poorly understood, but probably is a combination of factors. Unlike aortic dissections, no association with hypertension has been noted.8 The possible causes may be divided into three categories. Firstly, physiological changes during pregnancy are responsible for degeneration of collagen, 9 and subsequent haemodynamic stresses during delivery may then facilitate dissection. Vascular events are relatively common during pregnancy; 10–20% of all maternal deaths are secondary to vascular events.10 Secondly, rupture of the vas vasorum into the media has been implicated as an initiating site for coronary artery dissection.11 Finally, histological analysis of the involved area of coronary artery demonstrates periadventitial infiltration.2 These infiltrates consist of eosinophils, histiocytes, and lymphocytes. Robinowitz2 reported that these lymphocytes and eosinophils secrete lytic enzymes and major basic protein, leading to medial weakening and dissection.
The initial management of coronary artery dissection is similar to that of coronary artery disease without dissection. Early catheterisation is essential to determine diagnosis and guide subsequent management. There are several angio-graphical findings characteristic of spontaneous coronary artery dissection, including a radiolucent line that can be seen separating the true and false lumen of the vessel. This line represents the intima and inner portion of the media, which have been dislodged and now separate the true and false channels. The false lumen may appear as a saccular area next to the vessel. There may be compression of the true lumen by the false lumen, resulting in changes in the calibre of vessels.12
Prognosis is good for those who survive the initial event;7 12 year asymptomatic survival has been described with conservative management.13 The decision to thrombolyse may enable flow to be re-established in the true lumen; however, there is also the risk that thrombolysis may aggravate bleeding and the dissection.7 Patients who survive the initial event but remain unstable or suffer ongoing inducible ischaemia, as reported in this case, should be managed by interventional cardiology or surgery. Both angioplasty and stenting have also been described, with excellent results in single vessel disease, however, this must be balanced with the potential of entering the false lumen during passage of the guidewire and the risk of coronary occlusion or perforation.6 Previously, it has been recommended to perform coronary artery bypass surgery for all patients with spontaneous dissection,14 however, this must be considered in light of results achieved by stenting, difficulty noted in grafting the dissected artery, and perioperative morbidity and mortality.
Spontaneous coronary artery dissection is a rare condition that should be suspected and excluded in young women who present with acute coronary events. Management is reliant on immediate coronary angiography and should be individualised to angiographic findings and the patient’s response to initial aggressive medical management.
Competing interests: none declared
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