The reperfusion catheter is a 4.3F catheter with 30 holes over its distal 10 cm. It is used to maintain coronary blood flow in patients awaiting emergency coronary bypass surgery after failed coronary angioplasty. The insertion of the reperfusion catheter was attempted in 20 patients (14 with total occlusion and 6 with severe residual stenosis judged to be in jeopardy of reclosure before operation). The reperfusion catheter was successfully placed across the obstruction in 18 patients (90%). After successful insertion of the reperfusion catheter, 16 patients had good anterograde flow (Thrombolysis in Myocardial Infaction [TIMI] trial grade II or III); angiographic improvement was associated with significant lessening of ST segment elevation as well as a decrease in chest pain in most patients. Two patients had poor or absent anterograde flow (TIMI grade O or I) because of extensive preexisting intracoronary thrombosis; one died from refractory ventricular fibrillation. In each of the remaining patients emergency coronary bypass surgery was performed with no deaths or significant cardiac complications. The reperfusion catheter is a safe and effective method to reestablish and maintain coronary blood flow before coronary bypass surgery after failed coronary angioplasty. Because there is the potential risk of serious complications, particularly thrombus formation within this catheter, the reperfusion catheter should be used cautiously and the patient should undergo immediate bypass surgery.