[Risk of obstruction of secondary vessels in coronary angioplasty].

To define the risk of side branch occlusion during percutaneous transluminal coronary angioplasty (PTCA), 99 consecutive procedures, performed on 92 patients, were examined. In 77 of them side branches existed, originating from the stenosed segment; analysis was performed on 65 successful procedures (success rate = 84.4%). The 121 side branches were divided as follows: 53 (43.8%) originating from the stenosis itself (group A), of which 32 small in size (less than 1 mm) and 21 "moderate" (greater than or equal to 1 mm); 68 (56.2%) originating in the immediate vicinity of the stenosis (group B) of which 23 small and 45 moderate. After PTCA 3 side branches were occluded (2.5%): a small 1 of group A and 2 (1 small and 1 moderate) of group B. Three side branches (2.5%) all of group B, 1 small and 2 moderate, became stenotic in their take-off. In one only patient who had a side branch occlusion a slight CK-MB elevation (25 mU/ml) occurred together with a Q wave appearance in the aVL lead. In conclusion, side branches at risk are frequently present (in our population they account for 83.7% of the patients) but the real incidence of damage of these branches after PTCA is quite low, without any considerable difference between groups A and B, and significant clinical consequences are usually rare.