Cardiovascular · Year 1 · from Cardiovascular
Case 1: Aortic Dissection - Type A
Patient Presentation
Demographics: 58-year-old male
Chief Complaint: Sudden severe tearing chest pain radiating to back
History of Present Illness: A 58-year-old male with long-standing poorly controlled hypertension presents with sudden onset of severe "tearing" chest pain that began 2 hours ago while lifting heavy boxes. The pain started in his chest and immediately radiated to his back between his shoulder blades. He describes it as the worst pain of his life (10/10). He also reports feeling faint and notes that his right arm feels weak.
Physical Examination:
- Vital Signs: BP 185/110 mmHg (left arm), BP 125/78 mmHg (right arm), HR 105 bpm, RR 24/min, SpO2 96% on room air
- General: Diaphoretic, pale, severe distress
- Cardiovascular:
- Blood pressure differential >20 mmHg between arms
- Early diastolic decrescendo murmur (aortic regurgitation)
- Muffled heart sounds
- Neurologic: Right arm weakness (4/5 strength)
- Pulses: Diminished right radial pulse, normal left radial pulse
Workup
- ECG: Sinus tachycardia, nonspecific ST-T changes, no STEMI
- Chest X-ray: Widened mediastinum (9 cm), abnormal aortic contour
- CT Angiography (Chest/Abdomen/Pelvis):
- Intimal flap originating in ascending aorta
- Dissection extends from aortic root to descending aorta
- True and false lumens visualized
- Compression of right brachiocephalic artery (explains arm symptoms)
- Pericardial effusion (concerning for rupture)
- Echocardiogram: Moderate aortic regurgitation, dilated aortic root, intimal flap in ascending aorta
Diagnosis
Stanford Type A Aortic Dissection (DeBakey Type I) with complications: aortic regurgitation, brachiocephalic artery involvement, pericardial effusion
Vascular Physiology Correlation:
Aortic wall structure:
- Tunica intima: Endothelium (damaged in dissection)
- Tunica media: Elastic lamellae and smooth muscle (site of dissection plane)
- Tunica adventitia: Outer connective tissue layer
Pathophysiology:
- Intimal tear allows blood to enter the media
- Blood dissects through media creating false lumen
- Shear forces (related to dP/dt) propagate the dissection
- Pulsatile flow (Windkessel effect of aorta) worsens tear
Why tearing pain?
- Dissection through media stimulates aortic wall pain fibers
- Radiation follows path of dissection
Blood pressure differential:
- False lumen can compress branch vessels
- Right brachiocephalic involvement → reduced right arm BP
Aortic regurgitation: Dissection extends to aortic root → disrupts valve leaflet coaptation
Laplace's Law: Wall tension = (Pressure × Radius) / (2 × Wall thickness)
- Hypertension (↑P) increases wall stress
- Cystic medial degeneration (↓thickness) increases risk
Treatment
- EMERGENT surgical repair (Type A requires immediate surgery)
- Immediate BP and HR control:
- Target SBP 100-120 mmHg
- Target HR <60 bpm
- IV esmolol (reduces HR and dP/dt first)
- IV nicardipine (vasodilator after beta-blockade)
- Reduce shear stress (dP/dt) to prevent propagation
- Pain control: IV morphine
- Blood products available: Massive transfusion protocol
- Surgical approach: Ascending aorta replacement ± aortic valve repair/replacement
Clinical Image
Image Description: CT angiogram demonstrating Type A aortic dissection with visible intimal flap separating the true and false lumens in the ascending aorta. The false lumen often appears larger and may show slower contrast filling.
Source: Radiopaedia - Aortic dissection License: CC BY-NC-SA 3.0 URL: https://radiopaedia.org/cases/stanford-type-a-aortic-dissection