What is the recommended first‑line management for an acute Stanford type B aortic dissection and when is endovascular repair indicated?

Treatment of Acute Stanford Type B Aortic Dissection

Medical therapy with aggressive blood pressure and heart rate control is the first-line treatment for all patients with acute type B aortic dissection, with thoracic endovascular aortic repair (TEVAR) reserved for complicated cases or selected high-risk uncomplicated cases. 1

Initial Medical Management (All Patients)

Every patient with acute type B aortic dissection requires immediate medical therapy regardless of whether they ultimately need intervention 1:

• Administer intravenous beta-blockers as first-line antihypertensive therapy (esmolol, metoprolol, or labetalol) to achieve heart rate <60 bpm 1, 2
• Target systolic blood pressure <120 mmHg (specifically 100-120 mmHg range) to reduce aortic wall stress 1, 2
• Provide adequate pain control to achieve hemodynamic targets and reduce sympathetic surge 1
• If beta-blockers are contraindicated, use non-dihydropyridine calcium channel blockers 2

The sequence matters: control heart rate first with beta-blockers, then add additional agents for blood pressure control. This prevents reflex tachycardia that can worsen aortic wall stress 2.

Immediate Assessment for Complications

Rapidly evaluate for signs of complicated type B dissection, which changes management from medical to urgent intervention 1:

• Aortic rupture or impending rupture 1
• Malperfusion syndromes: cerebral/stroke, mesenteric ischemia, lower extremity ischemia, renal 1, 2
• Refractory pain despite adequate medical therapy 1
• Rapidly expanding aortic diameter 1
• Hemodynamic instability 3

Obtain ECG-gated CT angiography from neck to pelvis to evaluate dissection extent and identify complications 2.

Treatment Algorithm Based on Presentation

Uncomplicated Type B Dissection

Continue medical therapy with close surveillance as the definitive treatment 1:

• Maintain lifelong antihypertensive therapy with target long-term blood pressure <135/80 mmHg 1, 2
• Perform follow-up imaging at 1,3,6, and 12 months, then yearly if stable 1, 2
• Use MRI for follow-up (preferred) or CT (acceptable, especially in patients >60 years) to monitor for false lumen expansion, aneurysm formation, new tears, or malperfusion 1

Consider TEVAR in the subacute phase (14-90 days) for patients with high-risk anatomical features 1:

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

This represents an evolving area where endovascular repair may prevent late aortic complications in selected uncomplicated patients, though medical management remains first-line 1, 4, 3.

Complicated Type B Dissection

Emergency TEVAR is the first-line intervention for complicated cases 1, 2:

• TEVAR has replaced open surgical repair as the preferred treatment, contributing to a fourfold increase in early survival 4, 5
• The immediate goals are to reestablish true lumen flow, stabilize the aneurysm, and prevent rupture 6
• If malperfusion persists after TEVAR, perform angiographic control and/or additional percutaneous malperfusion repair 2

For lower extremity malperfusion specifically, TEVAR or EVAR with or without percutaneous malperfusion repair is first-line 2.

Long-Term Management and Surveillance

All patients require lifelong management regardless of initial treatment 1:

• Lifelong antihypertensive therapy to prevent aortic expansion and reduce complication risk 1
• For chronic type B dissection (>90 days) with descending thoracic aortic diameter ≥60 mm, intervention is recommended in reasonable surgical risk patients 1
• Consider intervention at ≥55 mm in low procedural risk patients 1
• Strict imaging surveillance continues indefinitely to detect late aneurysm formation or false lumen expansion 1, 5

Critical Pitfalls to Avoid

Do not delay medical therapy while arranging imaging or transfer – blood pressure and heart rate control must begin immediately 1, 2. The risk of rupture or propagation increases with every hour of uncontrolled hypertension.

Measure blood pressures in all four extremities to identify the highest central pressure, as dissection can produce falsely low peripheral readings that may lead to under-treatment 2, 7.

Do not assume uncomplicated dissection will remain uncomplicated – approximately one-third of type B dissections develop complications requiring intervention 6. Close surveillance is mandatory.

For pregnant patients with type B dissection, strict conservative medical management is recommended for both mother and fetus 1.