A 32 year old woman presented with acute myocardial infarction and left ventricular failure leading to acute mitral regurgitation. A coronary angiogram revealed a proximal stenosis of the left anterior descending artery (LAD), occlusion of the circumflex artery, and an aneurysm of the left main coronary artery, measuring 24 × 16 mm (panel A). A transoesophageal echocardiogram showed grade III mitral valve regurgitation secondary to annular dilatation and lateral wall dysfunction. The patient underwent surgery three weeks later. During the operation, the left main stem aneurysm containing multiple thrombi was over-sewn both proximally and distally. The LAD was grafted with the left internal thoracic artery, and intermediate and obtuse marginal arteries were grafted sequentially with a segment of the long saphenous vein. Failure in weaning off from cardiopulmonary bypass, because of the hypoperfusion within the LAD distribution, led to an additional vein graft to the LAD. The mitral valve was repaired using an annuloplasty band. The patient remains clinically asymptomatic; follow up computed tomographic coronary angiography six months later revealed an occluded left main stem and the aneurysm, and patent saphenous vein grafts to the LAD (panel B and C). As there are reports that such patients may also develop extracardiac aneurysms, she underwent a magnetic resonance imaging scan of head, thorax, and abdomen, which did not show any pathology.
Aneurysms of the left main coronary artery occur in 0.1% of adults. Only a few descriptions exist of a surgically treated aneurysm of the left main coronary artery. In this case, a direct approach was undertaken to close the aneurysm, and this was combined with mitral valve repair for ischaemic mitral regurgitation.
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