[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [General pathology](https://durgical.com/en/general-pathology/) › [Blood vessels](https://durgical.com/en/general-pathology/areas/vessels/) › Aortic dissection # Aortic dissection - Lesion Blood splits the layers of the aortic wall, tunnelling along the media. It causes tearing chest pain and can burst into the pericardium. Updated Nov 13, 2026 ## Key points - Hypertension is the main risk factor; Marfan, Loeys–Dietz, Ehlers–Danlos, bicuspid valve, Turner syndrome, pregnancy and cocaine also predispose. - Usually there is no prior aneurysm; the tear is often in the ascending aorta just above the valve. - The dissection plane runs between the middle and outer thirds of the media. - Type A (ascending aorta, with or without the descending) is the more common and more dangerous; type B spares the ascending aorta. - Death comes from rupture into the pericardium (tamponade), pleura or peritoneum, or from occlusion of branches. - Pain: sudden, tearing, anterior chest radiating to the back between the shoulder blades. ## What it is Aortic dissection occurs when blood enters the media, usually through an intimal tear, and separates its layers to form a blood-filled channel (false lumen). Most patients are men over 60 with long-standing hypertension; younger patients usually have a connective tissue disorder such as Marfan syndrome, or during pregnancy or cocaine use. Dissections of the ascending aorta (Stanford type A) are surgical emergencies; those limited to the descending aorta (type B) are often managed medically. ## Structure - Gross: an intimal tear with a blood clot dissecting within the wall; sometimes a ‘double-barrelled aorta’ when the false lumen re-enters and endothelialises. - Microscopy: cystic medial degeneration is common but not always present; inflammation is usually absent. ## Step by step - The media is weakened (cystic medial degeneration, hypertensive damage or a genetic matrix defect). - High shear stress opens a transverse tear in the intima. - Blood under arterial pressure enters the media and splits it along its length. - A false lumen forms; it may rupture outward, re-enter the true lumen or compress branches. - Extension into the aortic root distorts the valve (regurgitation), the coronary ostia (infarction) or the pericardium (tamponade). ## Clinical notes - Signs: unequal arm pulses or pressures, new aortic regurgitation murmur, stroke, limb ischemia, widened mediastinum. - Type A has high early mortality if not repaired; blood-pressure and heart-rate control are the first steps. ## Memory aid A tear in the lining, a tunnel in the wall: type A attacks the ascending aorta and the heart, type B stays behind. ## Test yourself Think of the answer, then tap the question to see it. ## What is the most important risk factor for aortic dissection? Hypertension; connective tissue disorders such as Marfan syndrome account for most cases in young people. ## Which part of the wall does the dissecting blood split? The media, usually between its middle and outer thirds. ## How does a proximal dissection cause sudden death? Rupture into the pericardium with tamponade, or involvement of the coronary ostia or aortic valve. ## What is the Stanford classification? Type A involves the ascending aorta (with or without the descending); type B is limited to the aorta distal to the left subclavian artery. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/general-pathology/aortic-dissection/) [More Pathology questions →](https://durgical.com/en/practice/?f=pathology) ## Elsewhere in DurgiPedia - [Fibrillin-1](https://durgical.com/en/biochemistry/enzymes/fibrillin-1/) - [Chest pain: ischemic, pericardial, pleural and other patterns](https://durgical.com/en/clinical-exam/chest-pain-ischemic-pericardial-pleural-and-other-patterns/) ## Connections ## Related 4 - [Aneurysms: types and pathogenesis](https://durgical.com/en/general-pathology/aneurysms-types-and-pathogenesis/) - [Hypertension: mechanisms](https://durgical.com/en/general-pathology/hypertension-mechanisms/) - [Pericardial disease](https://durgical.com/en/general-pathology/pericardial-disease/) - [Calcific valve disease](https://durgical.com/en/general-pathology/calcific-valve-disease/) ## Related conditions 8 - [Aortic dissection](https://durgical.com/en/conditions/aortic-dissection/) - [Marfan syndrome](https://durgical.com/en/conditions/marfan-syndrome/) - [Arterial hypertension](https://durgical.com/en/conditions/arterial-hypertension/) - [Cardiac tamponade](https://durgical.com/en/conditions/cardiac-tamponade/) - [Blunt traumatic aortic injury](https://durgical.com/en/conditions/blunt-traumatic-aortic-injury/) - [Aortic regurgitation](https://durgical.com/en/conditions/aortic-regurgitation/) - [Turner syndrome](https://durgical.com/en/conditions/turner-syndrome/) - [Cocaine and sympathomimetic toxicity](https://durgical.com/en/conditions/cocaine-and-sympathomimetic-toxicity/) [← All of general pathology](https://durgical.com/en/general-pathology/) Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given. Sources: [Aortic dissection: MedlinePlus Medical Encyclopedia](https://medlineplus.gov/ency/article/000181.htm) (MedlinePlus, US National Library of Medicine, 2025); [Marfan syndrome: MedlinePlus Genetics](https://medlineplus.gov/genetics/condition/marfan-syndrome/) (MedlinePlus, US National Library of Medicine, 2025). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/general-pathology/aortic-dissection/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/general-pathology/aortic-dissection/