A 62-year-old man with a history of hypertension and smoking presents with acute onset of severe, tearing back pain radiating to the left flank. Blood pressure is 180/110 mmHg in the right arm and 140/95 mmHg in the left arm. Femoral pulses are diminished bilaterally. A stat contrast-enhanced CT angiography (CTAE) of the chest and abdomen confirms a Stanford Type B aortic dissection extending into the abdominal aorta with involvement of the left renal artery ostium. What is the most appropriate immediate next step in management?

Explanation

## Acute Type B Aortic Dissection: Initial Management Strategy **Key Point:** Uncomplicated acute Type B (descending thoracic and abdominal aortic) dissections are managed medically with aggressive blood pressure and heart rate control as first-line therapy. Surgical or endovascular intervention is reserved for complicated dissections (rupture, malperfusion, uncontrolled hypertension despite medical therapy). ### Rationale for Medical Management **High-Yield:** The goal is to reduce aortic shear stress (dP/dt), achieved by: 1. Reducing systolic blood pressure to 100–120 mmHg 2. Reducing heart rate to 60 bpm or less 3. Using beta-blockers first (labetalol, esmolol) to reduce contractility 4. Adding vasodilators (sodium nitroprusside, nicardipine) if BP remains elevated **Mnemonic: ABCDE of Acute Aortic Dissection** - **A**gressive BP control (target SBP 100–120 mmHg) - **B**eta-blockers first (reduce dP/dt) - **C**ontrolled heart rate (target HR ≤60 bpm) - **D**iagnosis with CTAE or MRI - **E**ndovascular/surgical intervention only if complicated ### Why This Is NOT a Surgical Case (Yet) This is an **uncomplicated Type B dissection**: - No rupture or contained rupture - No acute malperfusion (renal artery involvement noted, but patient is stable) - No uncontrolled hypertension despite optimal medical therapy - No acute coronary syndrome or aortic regurgitation Surgical repair is indicated for: - Rupture or impending rupture - Acute malperfusion with end-organ damage (acute renal failure, mesenteric ischaemia) - Failure of medical therapy (recurrent pain, uncontrolled BP) - Chronic dissection with aneurysmal degeneration **Clinical Pearl:** ~90% of uncomplicated Type B dissections are managed medically with excellent long-term outcomes. Surgery/TEVAR is reserved for the ~10% with complications [cite:Harrison 21e Ch 242]. ### Why Stent Grafting Is Premature Thoracic endovascular aortic repair (TEVAR) is considered for: - Complicated Type B dissections (rupture, malperfusion, uncontrolled hypertension) - Chronic dissection with aneurysmal degeneration - Not for uncomplicated acute dissection as first-line therapy ### Why Renal Artery Stenting Is Not Indicated Renal artery involvement in dissection does not automatically require intervention. Renal perfusion may be maintained via the false lumen, and acute stenting carries risk of thrombosis and further ischaemia. Intervention is considered only if there is evidence of acute renal failure or progressive ischaemia despite medical optimization.