Abrupt coronary occlusion following conventional balloon angioplasty (PTCA) remains a serious complication afflicting up to 10% of patients. Although repeat PTCA for prolonged durations can restore blood flow in approximately 50% of patients, if this technique fails, the patient is generally referred for emergent coronary bypass surgery. In this report, we describe the use of directional coronary atherectomy (DCA) as a bail-out technique on 16 patients (17 lesions) undergoing angioplasty who demonstrated a flow limiting dissection and clinical evidence of ongoing ischemia following the procedure which could not be reversed with repeat dilatation (mean 3.5 inflations) at prolonged balloon inflations (mean 6.9 min). Ten of these patients presented to the hospital with a diagnosis of unstable angina and the remaining patients were admitted with acute myocardial infarction. The majority of the incidences of abrupt occlusion (83%) occurred while the patient was still in the cardiac catheterization laboratory. Successful rescue atherectomy was achieved in 15 of the target arteries (88%). In two patients, this technique failed to stabilize the artery and emergent coronary bypass surgery was performed. A complication related to the bail-out procedure developed in three of the successfully treated patients during the same hospitalization. Two patients experienced recurrent abrupt occlusion which was successfully treated with a repeat bail-out atherectomy procedure and one patient developed a non Q wave myocardial infarction. All patients were followed clinically for a mean interval of 9.93 months. Ten patients (71%) remained free of symptoms and cardiovascular events for this period. Stress electrocardiography was performed on eleven (79%) of the successfully treated patients and in no case was ischemia demonstrated.(ABSTRACT TRUNCATED AT 250 WORDS)