Unstable angina pectoris and post angioplasty restenosis are two very common coronary syndromes presenting as cardiac emergencies. In our preliminary analysis of fibroblast growth factors expression in atherectomy specimens from patients with unstable angina pectoris and post angioplasty restenosis we observed similarities in the histopathology of these two syndromes. The most significant observation in the two groups of patients was the abundance of smooth muscle cells. We therefore extended our interest to the histopathology of the atherectomy specimens with emphasis on the prevalence of vascular smooth muscle cells. Since the role of the smooth muscle cell in the pathogenesis of post angioplasty restenosis has been established we anticipate that by pointing out similarities in the histology of post angioplasty restenosis and unstable angina we will improve our understanding of unstable anginal syndrome. In the present study we will compare atherectomy specimens from patients with the two syndromes in regard to vascular smooth muscle cell predominance and lesion activity. Each specimen will be analyzed by three independent observers blinded to the clinical presentation of the patient.