High-grade de novo stenosis of the ostium (opening) of the right coronary artery I the middle-aged male (A) was free of calcification. Directional atherectomy using a 6 French device was successful (B).
Very complex shelflike de novo stenosis in the mid right coronary (C) and the site 2 years after successful directional atherectomy (D). Histology showed atheroma and organized thrombus. Flaplike de novo stenosis (E) was removed with directional atherectomy (F). Sites (A), (C), and (E) are poor lesions for conventional percutaneous transluminal coronary angioplasty (PTCA).

Douglas, Jr., J.S., M.D., King, III, S.B., M.D., Techniques of Percutaneous Transluminal Angioplasty and Atherectomy of the Coronary Arteries, The Hurst's The Heart, 8th ed., p 1348. (modified)

Figure 56a