Between August 1991 and December 1993, a total of 7011 percutaneous transluminal coronary angioplasties (PTCA) were performed. In 24 of them, the acute results were unsatisfactory, an autoperfusion balloon catheter was tolerated without complications and prolonged inflation (30 min to one hour) brought no improvement. In these 24 patients (22 men, two women; mean age 60 [33-81] years) the duration of inflation was, if possible, increased to at least 6 hours. In three patients the inflation had to be terminated after 2 or 4 hours, respectively, because of angina or for technical reasons. In 18 of the 24 patients subsequent angiography demonstrated residual restenosis of less than 50%, with a mean degree of stenosis of 18 +/- 14%. But lasting dilatation was not achieved in 6 patients: occlusion persisted in one and marked residual stenosis in two patients, while stent implantation was required in three. These results indicate that, in case of dissection or acute occlusion with failure after prolonged balloon inflation of 30 to 60 min, extending the duration of inflation to many hours can often produce good results so that stent implantation can be avoided.