What is the management for aortic dissection?

Management of Aortic Dissection

Acute Type A aortic dissection requires emergency surgical intervention to prevent fatal complications including aortic rupture, pericardial tamponade, and severe aortic regurgitation, while uncomplicated Type B dissection is managed medically with aggressive blood pressure and heart rate control. 1, 2

Initial Stabilization (All Dissections)

Immediate transfer to intensive care unit with invasive arterial line monitoring and continuous ECG is mandatory. 1

Hemodynamic Targets

• Target systolic blood pressure 100-120 mmHg and heart rate ≤60 beats per minute to reduce aortic wall shear stress 1, 2
• Administer intravenous beta-blockers as first-line therapy (propranolol, esmolol, or labetalol) 1, 2, 3
• If beta-blockers are contraindicated, use non-dihydropyridine calcium channel blockers 2
• Add sodium nitroprusside only after adequate beta-blockade if blood pressure remains elevated; never use vasodilators alone as this causes reflex tachycardia and increases aortic wall stress 1, 3

Pain Control and Imaging

• Administer morphine sulfate for pain control to reduce sympathetic stimulation 1
• Obtain urgent diagnostic imaging with CT angiography, transesophageal echocardiography, or MRI based on institutional capabilities and patient stability 1

Type A Dissection Management

Emergency surgical intervention is required for all Type A dissections to prevent rupture, tamponade, and relieve aortic regurgitation. 4, 1, 2

Surgical Approach

• Standard approach is median sternotomy with cardiopulmonary bypass 1
• Supracommisural graft implantation when the aortic root is normal and valve is intact 4, 2
• Valve resuspension using pledgetted transmural mattress sutures when commissures are detached (adequate in approximately 50% of chronic Type A cases) 4, 2
• Composite graft implantation with coronary artery reimplantation when the aortic root and valve are severely damaged 4, 2
• Subtotal or total arch replacement when dissection involves the arch or occurs in a previously aneurysmal arch, including reconnection of supraaortic vessels during hypothermic circulatory arrest 4, 2

Technical Considerations

• Dissected aortic layers are reconstituted using gelatin resorcinol formaldehyde (GRF) glue or teflon felt strips placed inside and outside the vessel 4, 1
• GRF glue produces firm union of dissected layers and converts them to leather-like texture, facilitating secure reconstruction while obliterating dead spaces 4
• Moderate hypothermia with equalized perfusion pressures during graft implantation 4, 1, 2

Type B Dissection Management

Uncomplicated Type B Dissection

Medical management with aggressive blood pressure and heart rate control is the standard approach for uncomplicated Type B dissections. 4, 1

• Continue intravenous beta-blockers targeting systolic BP 100-120 mmHg and HR ≤60 bpm 1, 3
• No proven superiority exists between surgical, endovascular stent grafting, or medical therapy alone for uncomplicated cases 4

Complicated Type B Dissection

Surgical or endovascular intervention is indicated for complicated Type B dissections with:

• Intractable or recurrent pain despite adequate medical therapy 4, 2
• Rapidly expanding aortic diameter 4, 2
• Periaortic or mediastinal hematoma indicating impending rupture 4
• Malperfusion syndromes affecting limbs, kidneys, or gut 4, 2
• Dissection in a previously aneurysmal aorta 4

Surgical Technique for Type B

• Posterolateral chest incision through the appropriate intercostal space for access to the descending aorta 4, 1, 2
• Replacement of affected portions with tubular graft of appropriate length 4, 1, 2
• Most surgeons use extracorporeal circulation via left heart bypass; femorofemoral bypass may be preferred for thoracoabdominal extension 4, 1

Endovascular Options

• Thoracic endovascular aortic repair (TEVAR) aims to cover the primary entry tear and redirect blood flow to the true lumen 1, 3
• Balloon fenestration of dissecting membrane plus stenting for dynamic obstruction of branch arteries 4
• Stenting of obstructed branch origins for static obstruction 4
• Covered stent placement to seal entry tears and enlarge compressed true lumen 4

Chronic Dissection Management

Chronic Type A

• Surgery indicated when aortic diameter exceeds 5-6 cm, symptoms develop, or significant aortic regurgitation occurs 2, 3
• Valve repair adequate in approximately 50% of chronic Type A cases when commissures require resuspension 4
• Catheter-guided fenestration of dissection membrane may be attempted for aortic arch involvement to decompress the true lumen; if unsuccessful, surgical intervention is required 4

Chronic Type B

• Operative intervention primarily directed at preventing expansion and threatening/manifest rupture 4
• Surgery indicated when diameter reaches 6.0 cm or progressive enlargement occurs 2, 3
• Indications for post-dissection aneurysms similar to other thoracoabdominal aneurysms 4

Long-Term Management

Medication Transition

• Transition from intravenous to oral beta-blockers after 24 hours of hemodynamic stability 1, 2
• Target long-term blood pressure <135/80 mmHg 1
• Lifelong beta-blocker therapy is mandatory for patients with hereditary connective tissue disorders (Marfan syndrome, Ehlers-Danlos syndrome) 1, 2, 3

Surveillance

• Regular imaging follow-up with MRI to monitor for false lumen expansion or aneurysm formation 1, 2, 3
• Consider reoperation when dissected aorta reaches 5-6 cm diameter 1, 2, 3
• Rate of reoperation for Type A dissection is approximately 10% at 5 years and up to 40% at 10 years, with even higher risk in Marfan syndrome patients 1, 2

Critical Pitfalls to Avoid

• Never administer vasodilators without prior beta-blockade as this causes reflex tachycardia and increases aortic wall stress 1, 3
• Avoid dihydropyridine calcium channel blockers without beta-blockers due to reflex tachycardia risk 1, 3
• In malperfusion scenarios, higher blood pressure may be temporarily tolerated to optimize perfusion to threatened organs 2
• Repeat sternotomy for chronic Type A requires extreme care as the aorta is usually unprotected by pericardium 2