Risk of side branch occlusion during coronary angioplasty.

To assess the risk of side branch occlusion during percutaneous transluminal coronary angioplasty (PTCA), 600 consecutive procedures were analyzed. On the basis of pre-PTCA angiograms of 557 patients in whom the balloon was actually inflated, 365 side branches in 302 patients (54% of patients) were deemed in jeopardy. A total of 122 side branches in 102 patients (18%) originated from the lesion segment itself, i.e., their take-off was narrowed (Group I, 33% of side branches at risk), whereas 243 side branches in 214 patients (38%) originated from the immediate vicinity of the stenosis in a way that they were subjected to temporary occlusion during balloon dilatation (Group II, 67% of side branches at risk). Patency of side branches was determined by consensus of 2 observers. Criteria for occlusion were disappearance, filling by collaterals, or stagnation of flow. After PTCA, 20 of 365 side branches (5%) were occluded and associated with chest pain in 5 patients, creatine kinase increase in 6, left anterior hemiblock, septal Q waves and transient atrial fibrillation in 1 and non-sustained ventricular tachycardia in 1 of the 20 patients. Exercise tolerance did not decrease. No local predilection for side branch occlusion was evident. Seventeen of 122 side branches (14%) occluded in Group I, compared with 3 of 243 (1%) in Group II (p less than 0.001). Thus, more than half of the patients who underwent PTCA had side branches at risk for iatrogenic occlusion.(ABSTRACT TRUNCATED AT 250 WORDS)