The emergency department refers a 72-year-old gentleman who woke up this morning with excruciating pain in his chest and between his scapulae, which he describes as ‘tearing’. He is known to have hypertension and has a 50 pack-year history of smoking. On examination he has a heart rate of 103 beats-per-minute (BPM) and a blood pressure (BP) of 190/101mmHg in the right arm and 171/97mmHg in the left. He has been moved to resus for intravenous (IV) opioids and to commence further investigation.