aortic dissection Flashcards
what is the etiology of aortic dissection ?
Acquired
Hypertension
Trauma, e.g., deceleration injury in a motor vehicle accident
Vasculitis with aortic involvement (e.g., syphilis, Takayasu arteritis)
use of amphetamines and cocaine
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congenital
connective tissue disease - marfan syndrome and ehlers dances syndrome
bicuspid aortic valve
what is the classification of aortic dissection
stanford type A
dissection involving the ascending aorta (proximal to the brachiocephalic artery)
requires surgery
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Stanford type B aortic dissection: any dissection not involving the ascending aorta
Descending aorta; originating distal to the left subclavian artery
Most cases can be managed with medical therapy (e.g., beta blockers, vasodilators).
clinical features of aortic dissection ?
Sudden and severe tearing/ripping pain
Location Anterior chest (ascending) or back (descending)
Interscapular or retrosternal pain - More common in cases of thoracic dissection (involving the descending aorta)
Neck and jaw - Aortic arch affected; dissection extends into the great vessels.
Abdomen or periumbilical, colicky pain - in cases of abdominal dissection
Character: migrates as the dissected wall propagates caudally
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Hypertension or hypotension
Asymmetrical blood pressure and pulse readings between limbs
(Depending on the dissection site, there may be discrepancies in pulse and blood pressure (carotid artery, subclavian artery, femoral artery). Occlusion of the subclavian artery can result in reduced peripheral pulses in the left arm, while occlusion of the brachiocephalic trunk can result in reduced blood circulation in the right arm. Occlusion of a femoral artery leads to a decreased pedal pulse on one side.)
Wide pulse pressure
Syncope, confusion, or agitation
diagnosis of aortic dissection
Order ECG for all patients.
CXR, TTE, and POCUS are considered screening imaging and are usually only obtained as the initial study if:
Invasive or risky testing is not desired for low-risk patients.
Definitive imaging is not readily available.
Patients are too unstable to undergo definitive imaging.
these are not sensitive enough to reliably rule out aortic dissection.
Definitive imaging includes CTA (gold standard), TEE (High accuracy: sensitive and specific; more reliable visualization), and MRA and should be obtained as the:
Initial study for high-risk patients
Confirmatory study if the diagnosis remains uncertai
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what is the management of aortic dissection ?
call for help to cardiothoracic surgeon
A-E
Establish IV access: two large-bore peripheral IV lines.
Obtain ECG.
Order laboratory studies: D-dimer, type and screen, CBC, coagulation panel, BMP, troponin
Begin hemodynamic monitoring, e.g., continuous telemetry, pulse oximetry, urine output, frequent BP checks.
CONTROLBLOOD PRESSURE
Initiate supportive care, e.g., pain management with IV morphine
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Stanford A dissection: immediate surgery
Open surgery with the replacement of the dissection with a polyester graft implantation
Stanford B dissection: treat conservatively (watchful waiting and ongoing medical therapy)
Blood pressure control: essential in all patients to prevent progression of the dissection
what is the management or hypotensive patients?
Hemodynamic support: target MAP of 70 mm Hg
IV fluids
Vasopressor support: if the patient remains hypotensive
Norepinephrine
Phenylephrine
Inotropes should be avoided as they can increase shear stress on the aortic wall through increased force of ventricular contraction
what is the management in hypertensive patients ?
Control hypertension and heart rate: target SBP 100–120 mm Hg and HR ≤ 60 beats per minute
Start with an IV beta blocker: to avoid reflex tachycardia
Esmolol
Labetalol
Followed by vasodilator (e.g., IV sodium nitroprusside)
Contraindications to beta blockers: Start a calcium channel blocker:
Verapamil
Diltiazem
what are the supportive care measures?
Adequate treatment of pain and anxiety helps reduce sympathetic tone, which reduces blood pressure and heart rate, thereby lowering shear stress.
Initiate pain management - morphine
Consider procedural sedation.
For patients taking anticoagulants, urgently consult hematology for consideration of anticoagulant reversal.
Identify and treat any complications (e.g., mesenteric ischemia, acute kidney injury).
what is the complication of aortic dissection
stanford A
Myocardial infarction (coronary artery occlusion)
can extend to the aortic valve - aortic regurgitation and cardiac tamponade
Pericarditis (slow extension of the dissection into the pericardium)
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Complications of both Stanford type A dissection and Stanford type B dissections
Bleeding into the thorax, mediastinum, and abdomen
Arterial occlusion followed by ischemia of the:
Celiac trunk, superior/inferior mesenteric artery → acute abdomen, ischemic colitis
Renal arteries → acute renal failure (oliguria, anuria)
Spinal arteries → weakness of lower extremities or acute paraplegia
PREVENTION OF AORTIC DISSECTION
Blood pressure control
Smoking cessation
