Results of percutaneous transluminal coronary angioplasty of high-risk angulated stenoses. Percutaneous transluminal coronary angioplasty (PTCA) of angulated stenoses has been found in studies using older PTCA equipment to be associated with a heightened risk of procedure-related major ischemic events. To better understand the factors associated with procedural risk and to identify means of lessening that risk, 100 patients, treated sequentially from 1986 to 1989, who underwent PTCA of stenoses located at greater than or equal to 45 degrees bends, were characterized for 27 clinical, anatomic and procedural variables. Clinical outcome of angioplasty was related to these variables. In addition, results from 344 consecutive contemporary patients undergoing PTCA of nonangulated lesions were compared to those of the study group. Procedural success was achieved in only 70% of patients with angulated stenoses, compared with 306 of 344 (89%) nonangulated stenoses, and major ischemic complications (death, bypass surgery or myocardial infarction) occurred in 13% of patients with angulated stenoses compared with 12 of 344 (3.5%) with nonangulated stenoses (both p less than 0.001). The presence of associated thrombus, stenosis length greater than 10 mm or age greater than or equal to 65 years led to an even higher risk of major complications (9 of 44 = 20.5%), whereas highly experienced angioplasty operators and the use of polyethylene terephthalate balloons appeared to decrease risk and increase the likelihood of success. PTCA of such stenoses should be undertaken only cautiously and in carefully selected patients. 