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Aortic Dissection (ADis)
Clinical Presentation: Sudden, severe pain with a “ripping” or “tearing” quality
In anterior chest: type A dissection (involves the ascending aorta)
Between the scapulae: type B dissection (involves decending thoracic and/or abdominal aorta)
Pain travels as the dissection propagates along the aorta
Other symptoms are those relating to the complications of ADis:
Rupture pericardial tamponade hemomediastinum
Occlusion of aortic branch vessels carotid (stroke) coronary (MI)
hemothorax (usually left sided)
splanchnic (organ infarction) renal (acute renal failure)
Distortion of aortic annulus aortic regurgitation
Physical Findings: Vitals: Hypertension often found either as the underlying cause of dissection, resulting from diminished renal vascular flow (renin-angiotensin system activation), or due to sympathetic nervous system response to severe pain
If dissection has occluded flow to one of the subclavian arteries, will see different systolic BPs in each arm
Neurologic: deficits (related to stroke) may be present if carotids are affected
Auscultation: If have Type A dissection (involving ascending aorta), may get aortic regurgitation, which means may hear an early diastolic murmur.
Etiology: Two postulated origins:
ADis might arise from a tear in the intimal layer, allowing blood from lumen to enter into the media and propagate along the plane of the muscle layer.
ADis might arise from rupture of the vasa vasorum (in the adventitia) w/ subsequent hemorrhage into the media, forming a hematoma in the arterial wall that then tears through the intima and into the vessel’s lumen.
Predisposition to ADis can come from any condition that interferes with the normal integrity of the elastic or muscular components of the medial layer. Some conditions that can predispose are:
Chronic HTN (more than 2/3 of ADis patients have HTN history)
Cystic medial degeneration (a feature of diseases including Marfan and Ehlers-Danlos)
Traumatic insult to the aorta may also incite dissection.
ADis is most common in ages 50-60 and in men.
Pathology: Two possible types of Aortic Dissection:
Type A: involves the ascending aorta (is most common with 65%) and may involve the arch (10%)
Type B: involves the descending thoracic aorta (20%) and/or abdominal aorta (5%)
Distinction of type A or B is important as is influences treatment strategy and prognosis. Type A ADis tends to be more devastating due to potential extension into the coronaries, arch vessels, and aortic valve support structures.
Dissections can be classified as acute or chronic: oAcute: present with duration of symptoms less than 2 weeks