What is the initial management of aortic dissection?

Initial Management of Aortic Dissection

Immediately initiate aggressive blood pressure and heart rate control with intravenous beta-blockers while simultaneously arranging urgent definitive imaging and surgical consultation, as mortality increases 1-2% per hour without treatment. 1

Immediate Stabilization and Monitoring

• Establish invasive arterial line monitoring and continuous three-lead ECG recording for precise blood pressure management 1
• Obtain intravenous access, draw blood samples, and transfer patient to intensive care unit 1
• Measure blood pressure in both arms to rule out pseudo-hypotension from brachiocephalic trunk involvement 2
• Provide adequate analgesia with morphine sulfate to reduce sympathetic surge and pain-related hypertension 1, 3

Blood Pressure and Heart Rate Control

First-line therapy is intravenous beta-blockers targeting systolic blood pressure <120 mmHg and heart rate ≤60 beats per minute. 1

Beta-Blocker Protocol

• Labetalol is the preferred agent due to its combined alpha- and beta-blocking properties, which optimally reduces aortic wall stress 1, 3
• Alternative beta-blockers include propranolol, esmolol, or metoprolol 1
• Never administer vasodilators without prior beta-blockade, as reflex tachycardia increases aortic wall shear stress and propagates dissection 2

If Beta-Blockers Are Contraindicated

• Use intravenous non-dihydropyridine calcium channel blockers (diltiazem or verapamil) for heart rate control 1, 3
• Avoid dihydropyridine calcium channel blockers (amlodipine, nifedipine) without beta-blockade due to reflex tachycardia 2, 3

Adjunctive Blood Pressure Control

• Add sodium nitroprusside or nicardipine only after achieving adequate beta-blockade if blood pressure targets remain unmet 1, 3

Exception for Malperfusion

• In cases of visceral or limb malperfusion, tolerate higher blood pressure (potentially >120 mmHg systolic) to optimize perfusion to threatened organs 1, 3
• Do not delay intervention in patients with ischemia, as 30-day mortality correlates directly with severity and duration of ischemia 1, 3

Urgent Diagnostic Imaging

Every patient with suspected aortic dissection requires urgent definitive imaging with CT angiography, transesophageal echocardiography (TEE), or MRI, all with sensitivity and specificity >90%. 1, 4

• CT angiography is most commonly used and readily available 1, 5
• TEE allows rapid bedside assessment with 86-100% sensitivity 1, 4, 6
• MRI has 95-100% sensitivity but is less practical in unstable patients 1, 4
• Chest X-ray is abnormal in 60-90% of cases but should be omitted in unstable patients to avoid treatment delays 1
• Selection should be based on patient stability and institutional capabilities 1

Type-Specific Management

Type A Dissection (Ascending Aorta)

Obtain urgent cardiothoracic surgical consultation immediately for emergency surgical repair. 1, 5

• Type A dissection has extremely high mortality (26-58%) and requires emergency open surgery to prevent aortic rupture, pericardial tamponade, and relieve aortic regurgitation 1, 4
• Surgical options include composite graft implantation in the ascending aorta with or without coronary artery reimplantation 1
• In cases with peripheral malperfusion, consider percutaneous revascularization first before surgical repair to allow ischemic injury to resolve 1

Type B Dissection (Descending Aorta)

Emergency TEVAR (Thoracic Endovascular Aortic Repair) is indicated for complicated Type B dissection with:

• Malperfusion syndrome (visceral, limb, or spinal cord ischemia) 1, 2, 7
• Rupture signs (periaortic/mediastinal hematoma, hemothorax, contrast extravasation) 2
• Intractable pain despite medical therapy 1, 2
• Rapidly expanding aortic diameter 1, 2
• Dissection in pre-existing aneurysm 1, 2

Uncomplicated Type B dissection is managed medically initially, with consideration for subacute TEVAR (14-90 days) if high-risk anatomical features are present 2:

• Maximum aortic diameter ≥40 mm 2
• Patent false lumen with diameter >22 mm 2
• Unfavorable entry tear location or extensive dissection 2

Transition to Oral Therapy

• Switch from intravenous to oral beta-blockers after 24 hours of hemodynamic stability if gastrointestinal function is preserved 1, 3
• Target long-term blood pressure <135/80 mmHg with beta-blockers as preferred agents, often requiring combination therapy 1, 3

Surveillance Protocol

All patients require serial imaging regardless of initial management approach. 2, 3

• MRI is preferred for follow-up as it avoids radiation exposure and nephrotoxic contrast 1, 2, 3
• CT is acceptable alternative, particularly in patients >60 years 1, 2, 3
• Imaging schedule: 1,3,6, and 12 months, then yearly if stable 2
• Monitor for false lumen expansion, aneurysm formation (threshold 5-6 cm diameter), new tears, or malperfusion 2, 3

Special Populations

• Patients with Marfan syndrome or Ehlers-Danlos syndrome require lifelong beta-adrenergic blockade for prevention of dissection 1, 3
• Pregnant patients require multidisciplinary team management at specialized centers using drugs with lowest teratogenic impact 1