Histologic analysis of directional coronary atherectomy samples. A review of findings and their clinical relevance.

Histologic analysis of atherectomy samples from > 400 patients who received directional coronary atherectomy at 3 separate institutions disclosed 2 major categories of tissue: atherosclerotic plaque (with or without thrombus) and intimal proliferation (hyperplasia, with or without thrombus). The predominant tissue type in atherectomy samples from native, primary, or de novo coronary artery stenoses was atherosclerotic plaque. The predominant tissue type in atherectomy samples from restenosis lesions (prior balloon angioplasty, atherectomy, or both) was intimal proliferation with variable amounts of atherosclerotic plaques (with or without thrombus). Deep vessel wall components (media, adventitia) were identified at varying frequencies. The clinical relevance of atherectomy tissue is reviewed.