A 58-year-old man with poorly controlled hypertension and significant smoking history presents with sudden-onset tearing chest pain radiating to the back, diaphoresis, and dyspnea. On examination, blood pressure is 200/110 mmHg in the right arm and 140/90 mmHg in the left arm, with a new diastolic murmur. CT angiography of the aorta demonstrates an intimal flap separating the true and false lumens extending from the ascending aorta through the arch to the iliac bifurcation. The structure marked **C** in the diagram shows partial thrombosis. Which of the following best describes the pathophysiological consequence of the structure marked **C** in this Stanford Type A aortic dissection?

Why option 2 is correct

The false lumen with thrombus (marked C) is a critical pathophysiological feature of aortic dissection. While partial thrombosis may initially limit flow, the false lumen remains a source of malperfusion through re-entry tears (communications between false and true lumens) that can compromise perfusion to vital organs and the true lumen itself. In Stanford Type A dissection, the false lumen extends from the ascending aorta through the arch and descending aorta, creating the potential for branch vessel involvement and hemodynamic compromise. The IRAD Registry and AHA/ACC guidelines emphasize that the false lumen dynamics—including partial thrombosis and re-entry points—directly influence malperfusion complications and long-term outcomes.

Why each distractor is wrong

IRAD Registry; AHA/ACC Aortic Disease Guidelines 2022