In a patient with an acute aortic dissection affecting both the ascending (type A) and descending (type B) aorta, what is the recommended immediate management, including surgical repair of the type A segment and medical therapy for the type B segment?

Management of Combined Type A and Type B Aortic Dissection

In a patient with acute aortic dissection involving both the ascending aorta (type A) and descending aorta (type B), emergency surgical repair of the type A component is mandatory to prevent death from rupture or tamponade, while the type B component is managed medically unless complications develop. 1, 2

Immediate Medical Stabilization

Before and during surgical preparation, aggressive medical management is critical:

• Initiate intravenous beta-blockers immediately to achieve target heart rate ≤60 beats per minute before addressing blood pressure 2, 3
• Target systolic blood pressure of 100-120 mmHg once heart rate is controlled 2, 4
• If blood pressure remains elevated despite beta-blockade, add vasodilators such as sodium nitroprusside 3
• Establish invasive arterial monitoring and continuous ECG recording for precise hemodynamic management 3
• Provide adequate analgesia with morphine sulfate and transfer to intensive care 3

Surgical Management of Type A Component

Emergency surgery for the type A dissection is the absolute priority and should not be delayed, as 50% of untreated patients die within 48 hours 1, 5. The surgical approach depends on the extent of aortic involvement and valve condition:

Surgical Decision Algorithm

If the aortic root is normal-sized and the valve is intact:

• Perform supracommissural tubular graft replacement at the sinotubular junction 1, 3
• If commissures are detached, resuspend the valve leaflets before graft insertion 1

If the aortic root is ectatic or the valve is abnormal:

• Implant a composite graft (valve plus ascending aortic tube graft) using the Bentall technique 1, 3
• This is particularly important in patients with Marfan syndrome or pre-existing annulo-aortic ectasia 5

If the dissection extends into the aortic arch:

• Consider subtotal or total arch replacement with reconnection of supraaortic vessels during hypothermic circulatory arrest 1, 3
• Use cerebral perfusion with cold blood at moderate hypothermia (28°C) to protect the central nervous system 5

Technical Considerations

• Access through median sternotomy with careful pericardial incision to avoid the friable dissected aorta 1
• Establish cardiopulmonary bypass via femoral artery and right atrium cannulation 1
• Reconstruct dissected aortic layers using either teflon felt strips or gelatin-resorcinol-formaldehyde (GRF) glue, with glue being technically easier and time-saving 1
• Resect the intimal tear whenever possible to prevent false lumen propagation 6, 5

Management of Type B Component

The type B dissection component is managed medically during and after type A repair unless complications develop 1. This approach is based on the lack of proven superiority of surgical intervention for uncomplicated type B dissections 1.

Indications for Type B Intervention

Surgical or endovascular intervention for the type B segment is indicated only if:

• Persistent or recurrent pain despite medical therapy 1
• Signs of early aortic expansion or impending rupture 1
• Malperfusion syndromes affecting mesenteric, renal, or limb circulation 1, 7
• Neurologic deficits from spinal cord ischemia 1
• Actual rupture 1, 7

Preferred Intervention for Complicated Type B

• Thoracic endovascular aortic repair (TEVAR) has replaced open surgery as the preferred treatment for complicated type B dissections due to lower morbidity and mortality 4, 7, 8
• Open surgical replacement with tubular graft remains an option when endovascular approach is not feasible 1, 3

Critical Pitfalls to Avoid

Never perform pericardiocentesis before surgery in patients with tamponade, as reducing intrapericardial pressure causes recurrent bleeding and hemodynamic collapse 2

Do not delay type A surgery for extensive imaging in hemodynamically unstable patients 2

Avoid calcium channel blockers without beta-blockers due to risk of reflex tachycardia that increases aortic wall shear stress 4

Be vigilant for malperfusion syndromes affecting cerebral, mesenteric, renal, or limb circulation, as these may require immediate surgical correction even before definitive aortic repair 2

Long-Term Management

After successful type A repair with uncomplicated type B component:

• Transition from intravenous to oral beta-blockers after 24 hours of hemodynamic stability 2, 3
• Maintain long-term blood pressure <135/80 mmHg with continued beta-blocker therapy 2
• Perform surveillance imaging with CT or MRI at 6 months, 12 months, then yearly if stable 2, 3
• MRI is preferred for long-term surveillance to avoid cumulative radiation exposure 2, 4

Indications for Delayed Type B Intervention

Consider intervention for the type B segment if:

• Descending thoracic aortic diameter reaches ≥60 mm in reasonable surgical risk patients 2
• Diameter reaches ≥55 mm in low procedural risk patients 2
• The dissected aorta becomes aneurysmal (5-6 cm diameter) 3, 4
• Progressive aortic enlargement or symptoms develop during follow-up 3

Special Populations

In patients with connective tissue disorders (Marfan syndrome, Ehlers-Danlos syndrome):

• Lifelong beta-blocker therapy is mandatory to prevent recurrent dissection 3
• Consider earlier intervention thresholds for aneurysmal degeneration 4
• The reoperation rate is significantly higher, approaching 40% at 10 years 3