71. Aortic Dissection

Question 1

Aortic dissection common sx

Answer 1

abrupt, sharp, severe pain maximally intense at onset in the chest or back. There may be various seemingly unconnected associated symptoms due to altered blood pres- sure or insufficiency of disparate vascular beds.

Question 2

Definitive dx for aortic dissection

Answer 2

most commonly made with an imaging study such as computed tomography of the aorta with intravenous contrast. A combi- nation of standardized clinical assessment, chest x-ray, and serum D-dimer testing can effectively rule out the condition in low-risk patients.

Question 3

Demographics of those presenting most often with aortic dissection

Answer 3

64y
65% male

Question 4

What are the three layers of the aorta?

Answer 4

inner endothelial intima, the smooth muscle media, and the connective tissue outer adventitia.

Question 5

Which layer of the aorta “feels” the changes of systole and diastole the most?

Answer 5

media, elastic fibers composed of elastin and fibrillin intertwine with collagen and smooth muscle cells, providing the viscoelastic prop- erties that enable the aorta to distend, storing a portion of the stroke volume and elastic potential energy during ventricular systole. The aorta then recoils during diastole so that blood continues to be pro- pelled to peripheral end organs.

Question 6

Describe the pathway of the aorta from the heart

Answer 6

aorta emanates from the left ventricular outflow tract of the heart, makes an approximate 180-degree curve, and travels posteri- orly within the mediastinum of the chest until it crosses through the diaphragm. It assumes a retroperitoneal position within the abdomen and continues inferiorly until it bisects into the common iliac arter- ies at approximately the level of the umbilicus

Question 7

Name 5 major arterial branches from the aorta and where

Answer 7

Chest - brachiocephalic, left common carotid, and left subclavian

Abdomen - celiac, superior mesenteric, bilateral renal and gonadal, and inferior mesenteric arteries

major supply to the anterior spinal artery and lumbar spinal cord via the artery of Adamkiewicz.

Question 8

What is the definition of aortic dissection?

Answer 8

separation of the media layer of the aortic wall, generally with formation of a hematoma or false lumen. This commonly occurs in the setting of degeneration of the medial layer with associated inflammation

Question 9

Define timeline for acute aortic dissection vs subacute vs chronic

Answer 9

acute if it is diagnosed within 2 weeks of symptom onset, subacute if diagnosed with 2 weeks to 3 months of onset, or chronic if greater than 3 months from onset.

Question 10

What is the Stanford classification description of aortic dissection?

Answer 10

Type A describes dissection involving the ascending aorta with or without descending involvement, and Type B dissection is limited to the descending aorta commencing distal to the left subclavian artery.

Question 11

Describe 2 classification systems for aortic dissection

Answer 11

Stanford
DeBakey

Question 12

What is the DeBakey classification description of aortic dissection?

Answer 12

type I, involving the ascending and descending aorta; type II, involving only the ascending aorta; and type III, limited to the descend- ing aorta

*These classification systems were proposed in part to differentiate patients who required surgical or pharmacologic ther- apy, though these delineations have blurred with modern therapeutic advances including endovascular treatments.

Question 13

How does aortic dissection cause problems? ie pathophys

Answer 13

most commonly occurs due to a tear in the inti- mal layer subsequent to a process that has weakened the aortic media. Blood passes through the tear separating the intima from the media or adventitia, creating a false lumen that can propagate in an antero- grade or retrograde fashion. Propagation of aortic dissection can cause complications such as visceral or neurologic malperfusion syndromes due to compromise of branch vessels, pericardial tamponade, or acute aortic insufficiency.

Question 14

What is an intramural hematoma? How is it diagnosed?

Answer 14

hematoma formation within the wall of the aorta without evidence of intimal aortic tear. The hematoma may be localized or dissect along the plane of the aortic media. The risk factors, presentation, and natural course of this variant generally mir- ror those of typical aortic dissection due to intimal tear. However, over half of intramural hematomas occur in the descending aorta as a result of atherosclerotic disease or iatrogenic intravascular catheter manipu- lation trauma.2 Intramural hematoma is most easily diagnosed with CT angiography and may be missed with conventional angiography.

Question 15

What is a penetrating atherosclerotic ulcer?

Answer 15

rosion of an intimal atherosclerotic lesion. It is an alternative mechanism to intimal tear, allowing blood to dissect into the media of the aortic wall or beyond. This process develops gradually in elderly patients with extensive ath- erosclerosis and often is heralded by chest or back pain and hyper- tension. Ulceration may lead to hematoma formation in the dissected media, or it can extend into the adventitia with pseudoaneurysm for- mation and potential rupture.

Question 16

Where does penetrating atherosclerotic ulcer often occur?

Answer 16

usually a localized process most commonly occurring in the descending aorta without retrograde aortic

Question 17

Using Stanford classification, what are mc types of aortic dissection?

Answer 17

two-thirds of aortic dissections are classified as type A, and the remainder as type B.

Question 18

Name 15 RF for any type of aortic dissection

Answer 18

HTN
cardiac surgery hx including ao valve replacement
aortic aneurysm
previous dissection
Marfan syndrome
atherosclerosis, a family history of thoracic aortic disease with or without a defined genetic syndrome, bicuspid aortic valve, coarctation of the aorta, a bovine-type aortic arch, when the brachiocephalic artery shares a common origin with the left common carotid artery, and infectious disease such as syphilis
events associated with increased aortic sheer force including crack cocaine use, weight lifting, the peripartum period
deceleration trauma can rarely cause aortic dissection
ther causative genetic syndromes include Turner, type 4 Ehlers-Danlos, and Loeys-Dietz. Fluoroquino- lones interfere with collagen synthesis and increase the risk of aortic dissection during treatment

Question 19

Name 8 sx of aortic dissection

Answer 19

acute severe, sharp, ripping or tearing, painful sensation in the chest or central upper back with maximal intensity from onset, and associated apprehension.5 When present, the pain generally radiates to the anterior chest or neck when the ascending aorta is involved, and to the back, abdomen, or down the legs when the pathology is in the descending thoracic aorta.
type A dissection include lightheaded sensation or syncope, and less commonly, dyspnea related to congestive heart failure.
atients with either type A or B dissection may complain of neurologic deficits related to cerebral or spinal cord compromise. Type B dissection is considered complicated in the setting of refractory pain, rapid aortic expansion or rupture, uncontrollable hypertension, or insufficient perfusion of the renal, splanchnic, spinal, or lower extrem- ity vasculature.

Question 20

Name 5 potential signs of aortic dissection on exam

Answer 20

asymmetric pulse deficits,6 and patients may present with hypertension, normotension, or hypoten- sion. Pseudohypotension may occur when the blood pressure in one arm is lowered due to subclavian artery compromise.
Syncope - oftne due to pericadial tamponade vs other causes include cerebrovascular insufficiency, internal hemorrhage with hypovolemia, or dysrhythmia.
A new diastolic mur- mur in the lower left sternal border suggestive of aortic regurgitation can occur when the dissection spans the aortic valve

Question 21

What is the “classic” but rare triad of aortic dissection?

Answer 21

abrupt tearing pain, pulse deficits, and aortic insufficiency

Question 22

What type of MI may be seen most commonly in sequale of type A dissection?

Answer 22

Acute myocardial infarction due to coronary ostium compromise may occur in type A dissection, with the majority of these cases involving the right coronary artery ostium with infarction of the corresponding inferior coronary territory. Left main occlusion is the second most com- mon site

Question 23

Type B dissection - what is the BP mc ?

Answer 23

The majority of patients with type B dissection have elevated blood pressure greater than 150 mm Hg. Syncope and pulse deficits can occur but are less common than with type A disease.

Question 24

What are 3 neuro sx that may occur with a type A or B dissection?

Answer 24

ischemic stroke, spinal ischemia leading to temporary or permanent paralysis in 1% to 3% of patients, and isch- emic peripheral neuropathy.

Question 25

What are 3 complications and or GI sx that may occur with aortic dissection?

Answer 25

due to fixed or dynamic arterial branch occlusion or global hypoperfusion. Mesenteric ischemia is the most common cause of death in type B disease. Gastrointestinal hemorrhage is less common and can be due to ischemic bowel or fistula formation. Nau- sea, vomiting, diaphoresis, and apprehension can be seen with all acute dissections.

Question 26

What is the aortic dissection detection risk score?

Answer 26

tool combining three domains of clinical information to assess for the risk of acute dissection: high risk conditions, pain features, and exam features (

Question 27

aortic dissection detection risk score - name 3 high risk conditions

Answer 27

marfan syndrome family hx aortic diseaes known ao valve disease recent aortic manip known thoracic ao aneurysm

Question 28

aortic dissection detection risk score - name 3 high risk pain features

Answer 28

chest, back or abdo pain describe as: abrupt onset, sev intensity, ripping or tearing

Question 29

aortic dissection detection risk score - name 3 high risk exam features

Answer 29

evidence perfusion deficit: pulse deficit systollic bp differential focal neuro deficit with pain murmur of ao insuff - new and with pain hypotension or shock state

Question 30

CXR sn of ao dissection

Answer 30

67%

Question 31

Name 8 findings of aortic dissection on cxr

Answer 31

widened mediastinum on AP at least 8cm at aortic knob mediastinal to chest width ratio exceeding 0.25. Separation of aortic intimal calcification from the external aortic wall pleural effusion normal left apical cap abnormal aortic contour aortic knuckle double ca sign >5mm tracheal shift deviated nasal gastric tube tracheal deviation R increased thickness of the left and or R paratracheal stripe opacification of the AP window obscuration of the aortic knob

Question 32

combined strategy of ADD=0 and negative D-dimer was__ sensitive for acute dissec- tion. Specificity was 18%

Answer 32

99.7%

Question 33

The diagnosis of aortic dissection ultimately rests on diagnostic imaging: recommended?

Answer 33

cta conventional angiog- raphy, magnetic resonance angiography (MRA), and transesophageal echocardiography (TEE)

Question 34

What is a "triple rule out" MDCTA protocol?

Answer 34

acute aortic dissection, myocardial infarction, and pulmonary embolism.

Question 35

Recommended ED management of ao dissection

Answer 35

1. ABCDE 2. esmolol infu- sion due to its short 9-minute half-life and titratability, or metoprolol or labetalol if esmolol is not readily available. Labetalol also provides alpha-1 adrenergic blockade decreasing vascular tone and blood pres- sure. A selective beta-1 receptor blocker such as esmolol or metoprolol may be preferred for patients with chronic obstructive pulmonary dis- ease (COPD) at risk for bronchospasm. for HR

Question 36

List 3 options of antiadrenergic medications and doses of acute aortic dissection

Answer 36

Esmolol 0.5 mg/kg over 1 minute, then 50 μg/kg/min infusion Increase by 50 μg/kg/min every 4 min to max. 300 μg/kg/min Repeat 0.5 mg/kg boluses with each increase in dosing Labetalol 10–20 mg up to every 10 minutes, or 0.5-2 mg/min infusion Metoprolol 2.5–5 mg every few minutes

Question 37

List 3 options of vasodilatory meds and doses of acute aortic dissection

Answer 37

Nitroprusside Begin 0.25–0.5 μg/kg/min and increase to max. 10 μg/kg/min Enalaprilat Begin 1.25 mg over 5 minutes, repeat up to 5 mg every 6 hours Calcium channel blockade Diltiazem Begin 10–20 mg, then 5 mg/hr infusion Infusion can be increased in 5 mg/hr increments up to 15 mg/hr Verapamil Begin 5 mg over 5 minutes, then repeat 5–10 mg up to every 15 minutes Or infuse 5 mg/hr with adjustment as needed

Question 38

List 2 vasopressor meds for acute aortic dissection

Answer 38

Norepinephrine Begin 5 μg/min and titrate up to mean arterial blood pressure goal of 65 mm Hg Phenylephrine Begin 50 μg/min and titrate up to mean arterial blood pressure goal of 65 mm Hg

Question 39

Type A vs type B management ao dissection

Answer 39

A = surgery B = meds

Question 40

Describe 2 examples of type A ao dissection surgical management techniques

Answer 40

Temporizing reperfusion: aortic stenting or fenestration, and selective branch stenting may allow stabilization and reduce the risk of the operation. Repair of the patient’s ascending aorta may proceed after a period of recovery. Definitive: resection of the dissected aorta segment and insertion of an aortic graft. Restoration of aortic valve competence is paramount in patients who develop aortic insufficiency. +/- Reimplantation of the coro- nary arteries to the new graft

Question 41

When to consider additional surgical management for type B dissection?

Answer 41

life-threatening complications such as ischemia of both kidneys leading to reversible renal failure, intestinal ischemia, limb ischemia, progressive aneurysm extension, impending or frank rupture, or intractable pain. However, modern endovascular therapy using stent grafts and fenestration is evolving this paradigm. The goals of this therapy include reconstruc- tion of the thoracic aorta segment containing the entry tear, induction of thrombosis of the false lumen, and reestablishment of the true aor- tic lumen and side-branch flow. Aortic fenestration is indicated for carefully selected patients with malperfusion syndrome due to branch artery occlusion,

Question 42

Name 5 complications of aortic dissection

Answer 42

The risk of death is increased in patients presenting with pericardial tam- ponade, coronary artery involvement leading to myocardial ischemia or infarction, or carotid artery involvement causing cerebral hypoper- fusion. The most common causes of death are aortic rupture, stroke, visceral ischemia, cardiac tamponade, and circulatory failure

Question 43

30 day mortality type B dissection without complication

Answer 43

10%

Question 44

30 day mortality type B dissection with complication

Answer 44

evelop ischemic complications with associated organ malperfusion syndrome, renal failure, visceral ischemia, or contained rupture often require urgent aortic repair, which carries a mortality of 20% by day 2 and 25% by day 30.

Question 45

Type A acute aortic dissection carries a mortal- ity of __ - __% per hour immediately after the onset of symptoms.

Answer 45

1-2

Question 46

What complications increase risk of death in a type A dissection?

Answer 46

The risk of death is increased in patients presenting with pericardial tam- ponade, coronary artery involvement leading to myocardial ischemia or infarction, or carotid artery involvement causing cerebral hypoper- fusion.

Question 47

** The long-term 1- and 3-year survival reported in the IRAD in the surgically treated patients surviving to hospital discharge are 96 ± 2.4% and 91 ± 3.9%, respectively, reflecting the timely surgical repair of the ascending aortic dissection.

Question 48

Patients who retain patency in the false channel of the aorta after either medical treatment or surgical repair have a significant risk of aneurysm forma- tion and rupture of the false channel, especially in the first __months

Answer 48

6

Question 49

Post repair: Expansion, rupture, or both are more common in patients who are older and have poorly controlled ___ and ?

Answer 49

hypertension and COPD.

Question 50

Complications after ao dissection repair - list 3

Answer 50

aneurysm formation and rupture expansion of aneursym redissection progressive ao insufficiency

Question 51

The single most important agent to treat acute aortic dissection is: a Nitroprusside. b Aspirin. c Antiadrenergic. d Enalaprilat.

Answer 51

C

Question 52

A 70-year-old man with a history of poorly controlled hypertension presents with sharp central severe chest pain. ECG, chest x-ray, and serum D-dimer are normal. The next appropriate step is: a Transthoracic echocardiography in the radiology suite. b CT angiogram of the aorta. c Check serial troponin, and discharge with close follow up if neg- ative. d Consult surgical service.

Answer 52

B

Question 53

You are working in a small rural hospital when you diagnose a type A aortic dissection based on CT angiogram of the aorta. Vital signs are heart rate 85 beats per minute and blood pressure 130/85 mm Hg. The high-volume referral center is 25 minutes away by ambulance ride. a Arrange for immediate transfer to high-volume center. b Stabilize with arterial and central lines and intubation, then arrange transfer. c Call the intensivist to arrange medical ICU admission on labeta- lol infusion. d Call the general surgeon on duty to organize emergent surgery at your facility.

Answer 53

A

Question 54

A 60-year-old woman presents with chest pain radiating to the back with onset while lifting a 50-lb pot in her garden, and her ECG demonstrates an inferior STEMI. The next appropriate step is: a MR angiogram of the chest. b Aspirin and TPA. c Diltiazem infusion. d Immediate cardiac catheterization with recommendation to interventional cardiologist for initial aortogram.

Answer 54

D

Question 55

The connective tissue disorder responsible for the most cases of acute aortic dissection is: a Ehlers-Danlos, type I. b Ehlers-Danlos, type IV. c Marfan syndrome. d Loeys-Dietz syndrome.

Answer 55

C

Question 56

There are about 150 million annual ED visits in the United States. An emergency physician who sees 3000 patients per year can expect to see an acute aortic dissection about every: a 6 months. b 1 year. c 5 years. d 15 years.

Answer 56

C