A transmural coronary dissection occurred immediately after elective angioplasty of a 90% stenosis of the proximal left anterior descending coronary artery (LAD) within the dilated segment and was followed by subepicardial bleeding (haemorrhagia per rhexin), although no perforation by the guide-wire or the balloon catheter took place. A subepicardial blood bolster led to rapid extravasal compression of the LAD distal from the PTCA site resulting in acute ischemia. None of the conventional rescue-interventions such as stents or autoperfusion catheters were likely to resolve this critical situation and the patient successfully underwent emergency bypass surgery.