A 62-year-old man with a history of long-standing hypertension presents to the emergency department with abrupt onset of severe, sharp chest pain that he describes as “tearing.” The pain radiates between his shoulder blades. He is diaphoretic and anxious. Vital signs: T 36.9°C (98.4°F), HR 112/min, RR 22/min, BP 198/104 mm Hg in the right arm and 162/90 mm Hg in the left arm. While being evaluated, he becomes briefly unresponsive and then awakens confused but without focal weakness. A widened mediastinum is seen on chest radiograph. Which of the following is the most appropriate definitive management?

(Assume the lesion involves the ascending aorta.)