Thrombus formation over a fissured coronary atheromatous plaque has been shown by post mortem histological examination to be the pathophysiological mechanism responsible for myocardial ischaemia in those patients who died following a crescendo pattern of angina. Histological examination of plaques responsible for a crescendo pattern of angina in patients who do not die has not been available until recently. We describe two patients who presented with a crescendo pattern of angina. A new technique of coronary revascularization, directional coronary atherectomy, produced symptomatic relief and resolution of myocardial ischaemia. Histological examination of material from the stenosis responsible for their myocardial ischaemia, obtained using this technique, confirmed thrombus formation overlying a fissured atheromatous plaque.