Occlusion of a coronary artery by an acute type A aortic dissection presents a life-threatening emergency that is rarely seen and easy to misdiagnose. We present the case of a 75-year-old male who experienced sudden onset of severe left-sided chest pain due to an acute type A aortic dissection that obstructed the right coronary artery. Following an initial misdiagnosis of acute coronary syndrome, imaging revealed the presence of an aortic dissection. An emergency modified Bentall procedure was performed, in which the damaged aorta and aortic valve were replaced.