A 65-year-old man presents to the emergency department with severe, tearing chest pain radiating to his back that began suddenly 90 minutes ago. He has a history of chronic hypertension but stopped taking his medications 2 months ago. He smokes 10 cigarettes daily and drinks 8 alcoholic drinks per week. His blood pressure is 190/110 mm Hg and his heart rate is 115 beats/min. Physical examination reveals tachycardia but is otherwise unremarkable. An electrocardiogram shows sinus tachycardia, evidence of left ventricular hypertrophy, and T-wave inversions in leads V5 and V6. A CT angiogram of the chest shows an intimal wall flap in the aorta.
Which of the following is the most appropriate next step in management of this patient?
The correct answer is:
C) Labetalol intravenous
The clinical presentation of this patient strongly suggests an acute aortic dissection, characterized by the sudden onset of severe, tearing chest pain radiating to the back, along with the findings of the CT angiogram. The initial management of acute aortic dissection focuses on reducing aortic wall shear stress and preventing further propagation of the dissection. This is achieved through anti-impulse therapy. Anti-impulse therapy is a medication regimen used to quickly manage blood pressure and heart rate in patients with acute aortic syndromes (AAS). The goal is to reduce aortic wall shear stress and the change in aortic pressure over time. The main line of therapy is to decrease resting heart rate to less than 60 beats/min and maintain systolic blood pressure of less than 120 mm Hg. Anti-impulse therapy is usually achieved with intravenous (IV) vasodilators and β-blockers, ideally in the intensive care unit with arterial line monitoring. The 2022 American Heart Association and American College of Cardiology aortic disease guidelines recommend IV β-blocker therapy as the first-line treatment for acute aortic dissection. Beta blockers reduce blood pressure by blocking the effects of epinephrine, or adrenaline, which relaxes the heart and slows it down.
Intravenous beta-blockers (e.g., labetalol, esmolol) are the preferred therapy as they decrease ventricular contractility, blood pressure, and heart rate, thereby reducing aortic wall shear stress. Labetalol has the added benefit of alpha-1 receptor blockade, causing peripheral vasodilation and further blood pressure reduction. Adequate pain control (e.g., morphine) is also crucial as it reduces sympathetic drive, lowering blood pressure, heart rate, and contractility. If beta blockade alone does not achieve a systolic blood pressure < <120 mm Hg, intravenous nitroprusside can be added.
Answer choice A: Captopril sublingual, is incorrect. Sublingual captopril is an ACE inhibitor that can lower blood pressure but is not as effective as beta-blockers in reducing aortic wall shear stress and can cause reflex sympathetic activation.
Answer choice B: Hydralazine intravenous. Hydralazine is primarily an arterial vasodilator, which can increase aortic shear stress and is typically avoided in acute aortic dissection.
Answer choice D: Nitroprusside intravenous, is incorrect. Nitroprusside is useful to lower blood pressure However, it should only be used after beta-blockade is established to prevent reflex sympathetic stimulation.
Answer choice E: Warfarin oral, is incorrect. Warfarin is an anticoagulant that is contraindicated in aortic dissection due to the risk of aortic rupture or extension of the dissection into the pericardial space (hemopericardium).
Key Learning Point
In acute aortic dissection, intravenous beta-blockers such as labetalol are the preferred initial management to reduce blood pressure, heart rate, and aortic wall shear stress.
