Five thousand consecutive percutaneous transluminal coronary angioplasties (PTCA) were electively performed between January 1988 and June 1993. They were analysed for the incidence of acute coronary occlusion, its acute treatment and subsequent course. In 133 patients (2.7%) the occlusion persisted. Recanalization by repeat PTCA was attempted in all of them, but succeeded in only 68 (51%). In 65 patients recanalization was impossible. In 25 of the latter--patients with a small infarct vessel and infarction having already occurred in the vessel's supply area while the haemodynamics remained stable--conservative treatment was practised. Acute surgical revascularization was undertaken in 30 patients (23%) with a large area and/or haemodynamic instability. In all, 14 patients died (overall death rate 0.28%, death rate of patients with occlusion 11%), ten of them before operative intervention was possible.--Not all coronary artery occlusions can be treated nonsurgically. Consequently, availability of surgical intervention at the place of elective PTCA is mandatory.