Beta-blockers are generally considered the first-line

therapy for acute dissection given their ability to reduce

both blood pressure and heart rate. Because of its short

duration of action and rapid onset, esmolol is an excellent

first-line agent. Start with a loading dose of 500 meg/kg

given over 1 minute followed by a continuous infusion at

50 meg/kg/min. If the desired ventricular response has not

been achieved within 5 minutes, repeat the loading dose

and increase the infusion to 1 00 meg/kg/min. If the desired

ventricular response has not been achieved within another

CHAPTER 17

5 minute span, give a third and final loading dose of

500 meg/kg and increase the infusion up to a max rate of

200 meg/kg/min.

Patients frequently remain hypertensive despite achieving the ideal heart rate. In such situations, begin a continuous

infusion of an arterial vasodilator such as nitroprusside

(0.3-3.0 mg!kg/min). Alternative vasodilators including nicardipine or clevidipine are acceptable. Regardless of which

medication is used, never initiate vasodilator therapy until the

heart rate is adequately suppressed with beta-blockers to

avoid reflex tachycardia and propagation of the dissection.

As an alternative, labetalol is a reasonable single agent

due to its selective a1 and nonselective beta-blocking properties. Give an initial dose of 1 0-20 mg as a slow N bolus

over 2 minutes. If the desired blood pressure and heart rate

are not achieved within 10 minutes, administer escalating

doses (ie, 20 mg, 40 mg, 80 mg, 1 60 mg) at 1 0-minute

intervals to a cumulative maximum dose of 300 mg.

Labetalol can also be given as a continuous infusion. Start

the infusion at 0.5 mg/min and increase by 0.5 mg/min

every 15 minutes to a max dose of 2.0 mg/min as necessary.

If necessary, additional boluses of N labetalol can be given

while concurrently titrating the infusion to more rapidly

achieve the goal heart rate and blood pressure. Stanford

type A dissections require prompt cardiothoracic consultation for operative repair, whereas type B dissections are

typically managed medically.

DISPOSITION

� Admission

All patients with an acute aortic dissection require hospital

admission to an intensive care unit setting.

� Discharge

A patient in whom aortic dissection has been ruled out

should be discharged only when there was an initial low

clinical suspicion and all other concerning etiologies for

the presenting complaints have been excluded. Patients

with known chronic aortic dissections can be safely discharged provided their blood pressure is adequately con ­

trolled and their presenting complaint is unrelated to the

underlying dissection. At times subspecialty consultation

may be necessary to assist with disposition.

SUGGESTED READING

Klompas M. Does this patient have an acute thoracic aortic

dissection? J Am Med Assoc. 2002;287:2262-2272.

Upadhye S, Schiff K. Acute aortic dissection in the emergency

department: Diagnostic challenges and evidence-based management. Emerg Med Clin N Am. 201 2;30:307-327.

Wittels K. Aortic emergencies. Emerg Med Clin N Am. 20 1 1;

29:789-800.