What is the management and treatment of aortic dissection?

Management and Treatment of Aortic Dissection

Acute Type A (ascending aorta) dissection requires emergency surgical intervention to prevent aortic rupture, pericardial tamponade, and death, while acute Type B (descending aorta) dissection is managed medically unless life-threatening complications develop. 1, 2

Immediate Stabilization and Medical Management

Blood Pressure and Heart Rate Control

• Establish invasive arterial line monitoring immediately and transfer to intensive care unit 1, 2
• Administer intravenous beta-blockers as first-line therapy, with labetalol preferred due to combined alpha- and beta-blocking properties 1, 2, 3
• Target systolic blood pressure <120 mmHg and heart rate ≤60 beats per minute 1, 2, 3
• If beta-blockers are contraindicated, use intravenous non-dihydropyridine calcium channel blockers (diltiazem or verapamil) for heart rate control 1, 2, 3
• For severe hypertension despite adequate beta-blockade, add sodium nitroprusside or nicardipine to further reduce blood pressure 1, 2, 3
• Provide adequate pain relief with morphine sulfate to reduce sympathetic surge 1, 2

Critical Pitfall to Avoid

• Never administer vasodilators (nitroprusside, dihydropyridine calcium channel blockers) without prior beta-blockade, as reflex tachycardia will increase aortic wall shear stress and propagate the dissection 3

Special Consideration for Malperfusion

• In cases of visceral or limb malperfusion, tolerate higher blood pressure (potentially >120 mmHg systolic) to optimize perfusion to threatened organs, as 30-day mortality correlates directly with severity and duration of ischemia 2, 3

Type A Dissection: Emergency Surgical Management

Surgical Indications and Goals

• All acute Type A dissections require emergency surgical intervention regardless of symptoms 4, 1, 2
• The primary goals are to prevent aortic rupture, relieve pericardial tamponade, and correct aortic regurgitation 4, 1

Surgical Techniques

• Implantation of a composite graft in the ascending aorta with or without coronary artery reimplantation is the standard approach 4, 1, 2
• When the aortic root is normal and the valve is intact, supracommisural graft implantation may be performed 4, 1
• If commissures are detached, valve resuspension is adequate in approximately 50% of chronic Type A cases 4, 1
• Subtotal or total arch replacement may be necessary when dissection extends into the arch, including reconnection of supraaortic vessels during hypothermic circulatory arrest 4, 1

Type B Dissection: Medical vs. Interventional Management

Uncomplicated Type B Dissection

• Uncomplicated acute Type B dissections are managed medically with aggressive blood pressure control, as there is no proven superiority of surgical or endovascular intervention over medical therapy 4
• Continue intensive medical therapy with intravenous beta-blockers targeting the same hemodynamic goals as Type A dissection 1, 2

Complicated Type B Dissection: Indications for Intervention

Emergency intervention (preferably thoracic endovascular aortic repair - TEVAR) is required for: 4, 2

• Intractable pain despite adequate medical therapy
• Rapidly expanding aortic diameter or periaortic/mediastinal hematoma suggesting impending rupture
• Malperfusion syndrome affecting limbs, kidneys, or gut
• Dissection occurring in a previously aneurysmatic aorta

Interventional Techniques for Complicated Type B

• Stenting of obstructed branch artery origins for static obstruction (Class I recommendation) 4
• Balloon fenestration of dissecting membrane plus stenting of aortic true lumen for dynamic obstruction (Class I recommendation) 4
• Covered stent placement to seal entry tear and enlarge compressed true lumen (Class I recommendation) 4
• Fenestration to provide re-entry tear for dead-end false lumen (Class I recommendation) 4

Transition to Long-Term Management

Medication Transition

• Switch from intravenous to oral beta-blockers after 24 hours of hemodynamic stability if gastrointestinal function is preserved 1, 2, 3
• Maintain long-term blood pressure <135/80 mmHg with beta-blockers as preferred agents, often requiring combination therapy 2, 3

Surveillance Imaging Protocol

• MRI is the preferred modality for serial follow-up as it avoids radiation exposure and nephrotoxic contrast agents 4, 1, 2, 3
• CT angiography is an acceptable alternative, particularly in patients >60 years 2
• Perform imaging at 6 months, 12 months, then annually if stable 3
• Monitor specifically for false lumen expansion, aneurysmal degeneration, and progression of dissection 4, 1, 2, 3

Chronic Dissection Management

Indications for Delayed Surgical Intervention

For chronic Type A dissection: 4, 1

• Development of symptoms
• Significant aortic regurgitation
• Aortic diameter exceeding 5-6 cm

For chronic Type B dissection: 4, 1, 3

• Development of symptoms
• Progressive aortic enlargement to 6.0 cm diameter
• Consider endovascular stenting if surgical indication exists and anatomy is suitable

Reoperation Considerations

• The rate of reoperation for Type A dissection is approximately 10% at 5 years and up to 40% at 10 years after primary surgery 4, 1
• Risk is even higher in patients with Marfan syndrome 4, 1
• Repeat sternotomy requires extreme care as the aorta is usually unprotected by the pericardium and may be adherent to the posterior sternum 4, 1

Special Populations

Hereditary Connective Tissue Disorders

• Lifelong beta-adrenergic blockade is mandatory for patients with Marfan syndrome or Ehlers-Danlos syndrome to prevent dissection 1, 2, 3

Pregnancy

• Management requires a multidisciplinary team at specialized centers, using drugs with the lowest teratogenic impact 1, 2