Myocardial ischemia during percutaneous transluminal coronary angioplasty in patients with rich collateral circulation of the target lesion.

Although it is commonly believed that ischemia does not develop during coronary intervention in patients with rich collateral circulation to the target vessel, ST changes are often observed, the study group comprised 40 consecutive patients who underwent elective percutaneous coronary angioplasty and who had rich collateral vessels to the target lesions. None had side branches in the target vessel that would be occluded by the angioplasty balloon. During the intervention, the 12-lead electrocardiogram was monitored for any change in the ST-T segment and 13 (32.5%) showed significant ST changes. Of these, 3 had ST changes with every balloon inflation and the remaining 10 patients had ST changes with the second or subsequent inflations. Myocardial ischemia caused by balloon inflation is not uncommon during coronary angioplasty in patients with rich collaterals to the target vessel. The collateral circulation may stop functioning very early after improvement in the forward flow of the target vessel.