What is the management of type B aortic dissection?

Management of Type B Aortic Dissection

Immediate Medical Management (All Patients)

All patients with type B aortic dissection require immediate aggressive medical therapy with blood pressure and heart rate control as the foundation of treatment, regardless of whether they are complicated or uncomplicated. 1

Hemodynamic Targets

• Target systolic blood pressure <120 mmHg and heart rate ≤60 bpm to reduce aortic wall stress 1
• Intravenous beta-blockers (labetalol preferred) are first-line agents 1
• Add intravenous vasodilators (dihydropyridine calcium blockers or nitrates) if beta-blockers alone are insufficient 1
• In patients with spinal ischemia or concomitant brain injury, maintain higher mean arterial pressure 1

Acute Phase Monitoring and Pain Control

• Invasive arterial line monitoring and continuous three-lead ECG in intensive care unit 1
• Adequate pain control to achieve hemodynamic targets 1
• After 24 hours of achieving hemodynamic targets with IV therapy, switch to oral beta-blockers if gastrointestinal transit is preserved 1

Risk Stratification: Complicated vs. Uncomplicated

Complicated Type B Dissection (Emergency Intervention Required)

In complicated acute type B aortic dissection, emergency intervention with TEVAR as first-line therapy is mandatory. 1

Complicated features include:

• Aortic rupture or impending rupture (periaortic/mediastinal hematoma) 1
• Malperfusion syndromes (cerebral, mesenteric, renal, lower limb) 1, 2
• Intractable pain despite optimal medical therapy 1, 2
• Rapidly expanding aortic diameter 1, 2
• Hemodynamic instability 3

TEVAR is recommended over open surgery for complicated type B dissection due to significantly improved early survival (fourfold increase) 1, 4

Uncomplicated Type B Dissection (Initial Medical Management)

For uncomplicated acute type B dissection, continue medical therapy with close surveillance as the primary treatment strategy. 1, 2

However, TEVAR in the subacute phase (14-90 days after onset) should be considered in selected patients with high-risk features to prevent future aortic complications 1, 2

High-risk features warranting subacute TEVAR consideration:

• Primary entry tear >10 mm 2
• Initial aortic diameter >40 mm 2
• Initial false lumen diameter >20 mm 2
• Partial false lumen thrombosis 2

Chronic Type B Dissection Management

Lifelong antihypertensive therapy is mandatory for all patients with chronic type B dissection to prevent aortic expansion and reduce complication risk 1, 2

Intervention Thresholds for Chronic Dissection

• Descending thoracic aortic diameter ≥60 mm: intervention recommended in patients at reasonable surgical risk 1, 2
• Descending thoracic aortic diameter ≥55 mm: intervention should be considered in low-risk patients 1
• Acute symptoms (malperfusion, rupture, disease progression): emergency intervention required 1

Technical Considerations for Chronic Disease

• Fenestrated/branched stent grafts may be considered for chronic post-dissection thoracoabdominal aneurysms when intervention is indicated 1
• Chronic dissections have reduced remodeling capacity due to thickened, rigid aortic walls and dissection membranes, making endovascular management more challenging than acute cases 5
• Persistent false lumen perfusion is the most limiting factor for endovascular success in chronic dissection 5

Surveillance Protocol

For Medically Managed Type B Dissection

Follow-up imaging (CT or MRI) is required at 1,3,6, and 12 months after onset, then yearly if imaging findings remain stable 1, 2

After Endovascular or Surgical Intervention

• Follow-up imaging at 1 month and 12 months post-operatively, then yearly until the fifth post-operative year 1
• If no complications occur within the first 5 years, imaging every 2 years thereafter 1
• If no residual patent false lumen is documented for 3 post-operative years, surveillance every 2-3 years 1

Common Pitfalls and Caveats

Avoid using beta-blockers as monotherapy without adequate blood pressure control - vasodilators alone can cause reflex tachycardia and increased aortic wall stress, worsening the dissection 1

Do not delay intervention in complicated dissection - mortality rates reach 50-85% in complicated type B dissection without proper treatment 3

Recognize that uncomplicated dissection at presentation does not guarantee long-term stability - medical therapy alone has 30-50% mortality at 5 years and 20-50% develop delayed false lumen expansion at 4 years, justifying consideration of subacute TEVAR in high-risk patients 3

Maintain strict blood pressure control lifelong - even after successful intervention, inadequate hypertension control leads to continued aortic expansion and late complications 1, 2