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Acute aortic dissection: Rapid overview of emergency management

Acute aortic dissection: Rapid overview of emergency management
Treatment of acute aortic dissection depends on the type/location. Aortic dissection involving the ascending aorta is a cardiac surgical emergency. Aortic dissection limited to the descending thoracic and/or the abdominal aorta can often be managed medically, unless there is evidence of end-organ ischemia, progression, or rupture.
Clinical features and evaluation
Acute onset of severe, sharp, or knife-like pain in the anterior chest, with radiation to the neck, back, or abdomen. Pain may be migratory.
Assess risk factors for TAAD*.
Palpate carotid, subclavian, and femoral pulses; note any significant differences between sides. Obtain blood pressure in both arms.
Auscultate for diastolic cardiac murmur of aortic regurgitation; assess for tamponade (muffled heart sounds, jugular venous distention, pulsus paradoxus).
Evaluate for signs of ischemic stroke, spinal cord ischemia, ischemic neuropathy, hypoxic encephalopathy.
Findings suggesting involvement of the ascending aorta include: back pain, anterior chest pain, hemodynamic instability, diastolic cardiac murmur, tamponade, syncope or stroke (persistent or transient; right hemispheric stroke is most common, but bilateral can occur), Horner syndrome (typically partial with ptosis/miosis), weak or absent carotid or subclavian pulse, upper extremity pain/paresthesia/motor deficit.
Findings suggesting involvement of the descending aorta include back pain, chest pain, abdominal pain, weak or absent femoral pulses, lower extremity pain/paresthesia/motor deficit, acute paraplegia.
Findings on initial studies
Obtain ECG. Look for signs of ACS; extension of type A dissection to coronary ostia can cause coronary ischemia (right coronary artery most commonly affected).
Obtain D-dimer, CBC, basic electrolytes, LDH, cardiac markers, coagulation parameters, and type and crossmatch. D-dimer <500 ng/dL is less likely to be aortic dissection.
Chest radiograph: Widened mediastinum and/or unexplained pleural effusion are consistent with dissection, particularly if unilateral.
Vascular imaging
For hemodynamically stable patient without suspicion for ascending aortic involvement: Obtain thoracic CT angiography or MR angiography, depending upon resources and speed of acquisition. Dissection is confirmed by presence of intimal flap separating true and false lumen. If these are not readily available or there is a contraindication, obtain transesophageal echocardiogram.
For hemodynamically unstable patient or for strong suspicion of ascending aortic involvement: Obtain transesophageal echocardiogram. If not immediately available, obtain CT angiography. Transthoracic echocardiography may help identify complications of ascending aortic dissection (eg, aortic valve regurgitation, hemopericardium, inferior ischemia) but is not sensitive for identification of dissection.
Management
Place two large bore IVs; monitor heart rate and blood pressure continuously, preferably using an arterial line.
Control heart rate and blood pressureΔ. Maintain heart rate <60 BPM and systolic blood pressure between 100 and 120 mmHg.
Administer esmolol (500 mcg/kg IV loading dose, then infuse at 25 to 50 mcg/kg per minute; titrate to maximum dose of 300 mcg/kg per minute) or labetalol (20 mg IV initially, followed by either 20 to 80 mg IV boluses every 10 minutes to a maximal dose of 300 mg, or an infusion of 0.5 to 2 mg/minute IV). If beta blockers are not tolerated, alternatives are verapamil or diltiazem.
Once heart rate is consistently <60 BPM, give vasodilator therapy. If the systolic blood pressure remains above 120 mmHg, initiate nitroprusside infusion (0.25 to 0.5 mcg/kg per minute titrated to a maximum of 10 mcg/kg per minute) or nicardipine infusion (5 mg/hour increasing every 5 minutes by 2.5 mg/hour to a maximum of 15 mg/hour). Vasodilator therapy (eg, nitroprusside, nicardipine) should not be used without first controlling heart rate with beta blockade.
Give IV opioids for analgesia (eg, fentanyl).
Place bladder (Foley) catheter to assess urine output and kidney perfusion.
Surgical consultation
Obtain immediate surgical consultation (cardiothoracic surgery, vascular surgery) as soon as the diagnosis is strongly suspected (particularly for involvement of the ascending aorta) or confirmed.
Aortic dissection involving the ascending aorta is a cardiac surgical emergency. Transesophageal echocardiography should be routinely performed in the operating room to assess aortic valve function, left ventricular function, aortic root and ascending aortic diameter, and evidence of hemopericardium/tamponade.
Aortic dissection involving only the descending thoracic aorta or abdominal aorta and with evidence of malperfusion is treated with urgent aortic stent-grafting or surgery.
Aortic dissection involving only the descending thoracic aorta or abdominal aorta without evidence for ischemia is admitted to the ICU for medical management of hemodynamics and serial aortic imaging.
If appropriate surgical services are not available, initiate emergency transfer to nearest available cardiovascular center.

TAAD: thoracic aortic aneurysm/dissection; ECG: electrocardiogram; ACS: acute coronary syndrome; CBC: complete blood count; LDH: lactate dehydrogenase; CT: computed tomography; MR: magnetic resonance; IV: intravenous; BPM: beats per minute; ICU: intensive care unit; AAA: abdominal aortic aneurysm.

* Known history of TAAD, AAA, aortic intramural hematoma, penetrating aortic ulcer, family history of TAAD or AAA, recent aortic instrumentation, known bicuspid aortic valve, known aortic coarctation, known syndrome associated with TAAD (eg, Marfan, vascular Ehlers-Danlos, Loeys-Dietz, or Turner syndromes).

¶ Amaurosis fugax has been reported.

Δ Patients should be admitted to an intensive care unit as rapidly as possible. Intravenous short-acting agents for control of heart rate and blood pressure should be administered immediately by clinicians who are trained and experienced in their titration using continuous noninvasive electronic monitoring of blood pressure, heart rate, and ECG. The use of non-selective beta blockers alone in patients with acute cocaine intoxication may lead to unopposed alpha stimulation worsening hypertension.

◊ Surgical services should include cardiothoracic/vascular surgery by surgeons experienced in the treatment of aortic dissection, equipment and technical support for cardiopulmonary bypass, and endovascular stent-graft capability.
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