A 58-year-old male with a history of hypertension and heavy smoking presents to the ER with 45 minutes of intense, 'tearing' chest pain that radiates to his back between the scapulae. He appears diaphoretic and distressed. On examination, there is a significant blood pressure difference (25 mmHg) between the right and left arms.
VITALS: HR: 115 bpm | BP (Right): 180/105 | BP (Left): 155/90 | RR: 22 | SpO2: 96%
❓ Based on the clinical presentation, what is the most likely diagnosis?