The authors summarize the early results of coronary angioplasty in 234 patients, with special emphasis on complications. The follow-up group included 182 men (77.8%) and 52 women (22.2%) with a mean age of 52 (34-74) years. Single-artery involvement prevailed (216 patients, 92.3%); multiple artery involvement was diagnosed in 18 patients (7.7%). Overall, dilatation was performed in 273 stenoses; of this number, 213 procedures were successful (78.0%). The primary success rate in the whole group was 76.9% (180/234). The highest success rates were attained in concentric stenoses (88.8%), the lowest ones in complete occlusions (53.8%). Complications were present in 36 patients (15.3%), of this number 14 patients (5.9%) developed acute arterial occlusion; the complications were less severe in 22 patients (9.4%). Of the 14 patients with acute occlusion, eight (3.5%) developed severe complications. One female patient (0.43%) died, one (0.43%) had emergency surgery, and six (2.6%) developed uncomplicated acute myocardial infarction. Perfusion was restored by multiple dilatation in four patients; arterial occlusion, with good collateral circulation, did not result in myocardial infarction in two. Other complications were less severe and had no sequelae including, most often, arterial spasm (3.4%), large dissection demonstrated by angiography (2.6%), protracted hypotension (0.8%), and ventricular fibrillation in one case (0.43%). The article also considers the factors raising the risk of severe complications of coronary angioplasty, and the potential for their prevention and treatment. Coronary angioplasty, employed in an increasing number of patients with symptomatic stenosing atherosclerosis of the coronary arteries, is an effective method successful in 85-95% of patients. The complication rate, while low, is not absolutely negligible.(ABSTRACT TRUNCATED AT 250 WORDS)