[Histopathological findings of coronary artery lesions resected by directional coronary atherectomy].

Eleven directional coronary atherectomy procedures were performed in seven patients with angina pectoris and four patients with myocardial infarction, 10 men and 1 woman aged 41 to 69 years (mean 57 +/- 7 years). The onset of angina pectoris or myocardial infarction had occurred 2 months to 17 years previously. The preoperative mean diameter of stenosis was 80 +/- 8%, and the mean residual diameter of stenosis was 6 +/- 9% (p < 0.01). Seven left anterior descending arteries and four right coronary arteries were treated. Five of the 11 patients received partial-thickness resections of medial tissue and two of the five patients received full-thickness resections of the media with adventitial tissue. No lesions showed aneurysms or perforations during coronary arteriography after the procedure. The resected tissue was examined microscopically. Intimal tissues stained with Masson's trichrome were classified into four groups according to the characteristics fibrous tissue and the amount of proliferative cells: Type I was old dense fibrous tissue, type II was relatively old fibrous tissue containing many proliferative cells, type III was new loose fibrous tissue containing many proliferative cells, and type IV was atheromatous plaque. The intimal tissues were type I in 48.0%; type II in 35.5%; type III in 14.8%; and type IV in 1.7%. Resected lesions without prior treatment (primary lesions) from five patients with histories of 3 months or less were characterized by much type II and type III tissue; (type I tissue, 33.8%; type II tissue, 51.1%; type III tissue, 14.5%; type IV tissue, 0.6%).(ABSTRACT TRUNCATED AT 250 WORDS)