Thoracic endovascular aortic repair (TEVAR) is still associated with complications which include mortality in 7.3% of cases. In this report, we describe the case of a man with a pseudoaneurysm of the aortic isthmus that was scheduled to undergo endovascular repair. During the procedure, the patient had a sudden cardiac arrest due to a compressive hemopericardium caused by perforation of the ascending aorta. The diagnosis was not clear and was made by transthoracic echocardiography after five minutes of resuscitation. In spite of the evacuation of the hemopericardium and suture of the perforation, the patient died. The diagnosis would have been easier and faster if the patient had been monitored continuously by transesophageal echocardiography during the procedure.