Examkin

Question

Difficulty: Very hardCardiovascular System

A 6464-year-old man is brought to the emergency department via ambulance due to the sudden onset of severe, "tearing" anterior chest pain that radiates to his back. He has a history of long-standing, poorly controlled hypertension. On arrival, he appears diaphoretic and in severe distress. Blood pressure is 210/110210/110 mmHg in the right arm and 170/90170/90 mmHg in the left arm. Heart rate is 112112/min. Physical examination reveals an early diastolic decrescendo murmur auscultated at the right upper sternal border. Neurological examination is unremarkable. Electrocardiogram shows left ventricular hypertrophy without acute ischemic changes. Arrange the following management steps in the most appropriate sequential order for this patient.

  1. 1Initiate intravenous esmolol therapy
  2. 2Initiate intravenous sodium nitroprusside therapy
  3. 3Obtain computed tomography angiography of the aorta
  4. 4Proceed to emergent cardiothoracic surgical repair

Answer

The correct sequential order for managing suspected acute Type A aortic dissection is to first administer intravenous beta-blockers (esmolol), followed by intravenous vasodilators (sodium nitroprusside), then obtain definitive imaging (computed tomography angiography), and finally proceed to emergent surgical repair.
The correct sequence prioritizes immediate anti-impulse therapy to halt dissection propagation, strictly adhering to the physiological rule that heart rate (dP/dt) must be controlled before blood pressure, followed subsequently by definitive diagnostic imaging and definitive surgical management.

Step-by-Step Solution

1
Initiate intravenous esmolol therapy
Decreases heart rate to a target of <60<60/min and reduces left ventricular contractility.
Must be given first to decrease the rate of rise of aortic pressure (dP/dt), minimizing aortic wall shear stress and preventing further dissection propagation.
2
Initiate intravenous sodium nitroprusside therapy
Lowers systolic blood pressure to a target of 100−120100-120 mmHg.
Must be given only AFTER beta-blockade is established; if given first, vasodilators cause reflex tachycardia and increased contractility, which worsens shear stress and propagates the intimal tear.
3
Obtain computed tomography angiography of the aorta
Confirms the diagnosis and delineates the extent of the dissection.
Once the patient is hemodynamically stabilized with anti-impulse medical therapy, definitive non-invasive imaging is required to confirm the presence of an intimal flap and identify ascending aorta involvement (Stanford Type A).
4
Proceed to emergent cardiothoracic surgical repair
Provides definitive anatomical treatment of the Type A dissection.
Type A dissections (suggested clinically here by the new aortic regurgitation murmur) have a very high short-term mortality rate due to complications like cardiac tamponade, aortic rupture, or coronary artery occlusion, requiring emergent open surgery.

Key Concept

In the management of highly suspected acute aortic dissection, intravenous beta-blockers must be administered before intravenous vasodilators to prevent reflex tachycardia and increased aortic wall shear stress. Immediate hemodynamic stabilization strictly precedes definitive imaging and surgical repair.

Alternative Method

In cases where beta-blockers are strictly contraindicated (e.g., severe reactive airway disease, high-degree AV block), intravenous non-dihydropyridine calcium channel blockers like diltiazem or verapamil can be used for initial heart rate control prior to vasodilator therapy.
Estimated Time:2m 0s
Rate this question

Topics

Cardiovascular System

More questions from this topic