Morphology after Transluminal Angioplasty

To the Editor: Microscopic sections of the coronary vessels after transluminal angioplasty, discussed in the article by Block et al. (August 13 issue),* have striking implications for angiographic assessment of the efficacy of this new procedure. In both cases the enlargement of the lumen occurred through the development of a slit along the internal-circumference vessel: in the first patient the slit was an almost circumferential, thin one, and in the second it was a more limited, very narrow one along the vessel wall. The angiographic evaluation of these lesions presumably would overestimate the luminal size. For example, in Case 1.