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Aortic Emergencies

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Title: Aortic Emergencies


1
Aortic Emergencies
  • David Peterson
  • February 3, 2005

2
Objectives
  • Define aortic dissection AAA and demonstrate
    their clinical relevance
  • Review pathophysiology and classification
  • Discuss diagnostic modalities
  • Discuss management options
  • Series of questions and cases

3
PERSPECTIVE
  • 1955 DeBakey outlined principles that remain
    basis for surgical treatment of aortic dissection
  • Medical treatment of aortic dissection was first
    advocated in the 1960s and is indicated for
    certain types of dissections

4
Aortic Dissection
  • longitudinal cleavage of the aortic media
    created by a dissecting column of blood
  • Rosens Emergency Medicine

5
(A) Normal blood flow in the aorta. (B)
Dissection occurs when the inner lining of the
aorta tears and the blood flow dissects between
the layers of the aortic wall
6
Aortic Dissection
John Ritter Age 54 DEAD
7
Epidemiology
  • Underreported
  • Hypertension is the most common risk factor
    associated with aortic dissection and is seen in
    most patients
  • Incidence 5-10/ 1,000,000 and rising
  • Mortality 1-2/hour (33 in 1st 24 hrs)
  • High rate of misdiagnosis 28
  • One study suggests EPs suspect AD in lt50 of
    cases
  • Sullivan et al. Am J Emerg Med 18 46-50. 2000
  • Variable presentation including MI
  • Lack of suspicion for AD is 1 cause of
    misdiagnosis

8
Epidemiology
  • History of cardiac surgery present 18 and
    bicuspid aortic valve in 14 of all patients with
    aortic dissection
  • more often in proximal dissections
  • Atherosclerosis rarely involved at site of
    dissection
  • Aortic dissection uncommon before age 40 except
  • Congenital heart disease, Ehlers-Danlos or Marfan
    syndrome, giant cell arteritis and possibly
    pregnancy
  • 44 of patients with Marfan syndrome develop
    aortic dissection and account for 6 of such
    cases

9
Ehlers-Danlos
10
Marfan Syndrome
11
Anatomy and Physiology
  • Each contraction the heart swings side to side
    resulting in flexion of both ascending aorta and
    descending aorta
  • Descending aorta flexes just distal to left
    subclavian artery where mobile aorta is tethered
  • At 70 heartbeats per minute sequence occurs 37
    million times a year causing repetitive stress on
    the aorta

12
Anatomy and Physiology
  • The aortic wall has three distinct layers the
    intima, the media, and the adventitia
  • The media is comprised of elastic tissue and
    smooth muscle
  • MEDIA Middle
  • INTIMA Inside

13
Pathophysiology
  • Requires 3 basic features
  • Abnormal media
  • Blood entry into media by intimal tear
  • Pressure forces favoring propagation

14
Pathophysiology
15
Pathophysiology
  • Arterial Obstruction is caused by 2 mechanisms
  • By compressing from the expanding hematoma
  • From occlusion of lumen by intimal flap
  • This results in peripheral complications
  • Cerebral ? CVA, syncope
  • Spinal ? Neuro deficits
  • Cardiac ? MI, tamponade, AR
  • Respiratory ? Hemoptysis, pleural effusion
  • GI ? Hematemesis, dysphagia, mesenteric ischemia
  • Renal ? ARF, HTN
  • Limbs ? Extremity ischemia

16
CT AD Intimal Flap
17
Pathophysiology
  • Intimal tears occur in 96 of all AD cases
  • Felt to occur 2o to shearing forces and
    hemodynamic stresses
  • Propagation factors
  • Degree of HTN
  • Slope of pulse wave (dP/dT)
  • Spontaneous cure rupture back into true lumen
    (rare)

18
Aortic dissection bursts into the pericardium
  • Pericardial Tamponade

19
  • Hemopericardium and tamponade can occur with
    dissection into pericardial sac

20
The tear progresses down to and occludes the
coronary artery precipitating an MI
  • Almost always an inferoposterior MI RCA

21
  • Coronary artery involvement in 1 ? presents as
    MI
  • 0.1-0.2 of MIs are complicated by incorrect
    admin of lytics in
  • setting of AD

22
The tear can disrupt the aortic valve, producing
acute valvular insufficiency, a common cause of
acute CHF and increased risk of death
AR
23
Clinical Presentation
  • Sudden, severe chest pain (76-90)
  • Migratory CP is highly specific (71)
  • Back pain (53), abd pain
  • Other Sx depending on site of involvement
  • Syncope (9)
  • Neuro Sx (6-13)
  • Mesenteric ischemia
  • Renal failure
  • Can be painless in up to 15 (chronic)

Moore et al. Am J Card. 891235-1238 2002 Hals.
Emerg Med Reports 2000
24
Risk Factors for AD
  • Hypertension (60-90)
  • Age 50-70 yo
  • Male (31)
  • CTDs (Marfans 5, Ehlers-Danlos)
  • Turners, Coarctation, Ebsteins Anomaly
  • Congenital bi-/tricuspid AV
  • Family Hx or previous dissection
  • Cocaine, metamphetamine
  • Iatrogenic
  • Trauma

Hals. Emerg Med Reports 2000
25
Classification
  • DeBakey
  • Type I involve ascending aorta, arch, and
    descending aorta
  • Type II ascending aorta proximal to L subclavian
    artery
  • Type IIIa descending aorta only above diaphragm
    only
  • Type IIIb descending aorta only extension below
    diaphragm

26
DeBakey
27
Stanford
  • Type A involvement of ascending aorta
  • Type B no involvement of ascending aorta
  • 62.5 of pts w/ AD have a Type A
  • Involvement of ascending aorta is of prognostic
    and therapeutic importance

28
Diagnosing AD
  • Clinical suspicion above all
  • 3 clinical variables shown to be useful
  • Aortic pain (immediate onset, tearing, ripping)
  • Mediastinal widening / aortic widening on CXR
  • Pulse or BP differentials
  • Likelihood of AD
  • Ø of above variables ? 7 risk of AD
  • Pain or widening alone ? 31 39 risk of AD
    respectively
  • gt 2 variables or isolated BP / pulse diff ? gt 83
    risk of AD
  • Von Kodolitsch et al. Arch Intern Med. 160
    2977-82. 2000
  • Diagnostic modalities
  • ECG, CXR, CT, TEE, Angiogram, MRI

29
ECG findings in AD
  • 85 will be abnormal
  • LVH
  • Non-specific ST-T wave changes
  • MI (RCA most common)
  • Bottom line
  • not sensitive or specific
  • beware thrombolysis until AD excluded

30
CXR findings in AD
  • 80-90 will be abnormal
  • Most findings non-specific
  • Mediastinal widening (59-75)
  • Calcium sign (pathognomonic)
  • Double density aorta
  • Obliteration of aortic knuckle
  • Loss of PA window
  • Tracheal deviation to right
  • Depressed left main stem bronchus
  • New left pleural effusion
  • Apical cap
  • Size disparity of ascending descending aorta

31
CXR
32
TEE
  • Rosen 98 sensitive, 77 specific
  • Moore et al 88 sensitive
  • 1st test in Europe and Japan
  • Advantages
  • Can differentiate Type A B dissections
  • Rapid, can be done at bedside
  • No contrast or radiation
  • Can detect AR and pericardial effusion
  • Disadvantages
  • Availability, operator dependence
  • Limited info on distal aorta

Moore et al. Am J Card. 891235-1238. 2002
33
TEE Aortic Dissection
Intra-operative TEE echo demonstrating high
velocity jet striking aortic wall at point of
intimal injury
34
CT scanning
  • Dynamic helical CT nearly 100 sensitive and
    specific (dye) (Moore et al 93 sens)
  • Advantages
  • Availability, can differentiate Type A B
  • Able to identify sealed-off false lumens
  • Able to identify other pathology (eg PE)
  • Disadvantages
  • Dye reactions (1/10,000 fatal)
  • No info on AV function or intimal tear location
  • No info about extension into other arteries

35
CT Aortic Dissection
CT of abdominal aorta show intimal flap (dark
line) with true lumen anteriorly and false lumen
posteriorly
36
CT Aortic Dissection
Stanford Type A Aortic Dissection
37
CT Aortic Dissection
Stanford Type A Aortic Dissection
38
Angiography
  • 81-87 sensitive, 96 specific
  • Previous gold standard
  • Advantages
  • Anatomical delineation of aortic tree
  • Ability to demonstrate AR
  • Can differentiate Type A B dissections
  • Disadvantages
  • False ves due to false lumen thrombosis
  • Invasive, time consuming, expensive

39
Angiography
40
MRI
  • Near 100 sensitivity and specificity
  • No role in critical pts but good for serial
    follow-up
  • Advantages
  • Excellent anatomical delineation, info on AR,
    intimal tear location, type and extent of AD
  • Disadvantages
  • Time-consuming
  • Unable to monitor pt

41
MRI
42
Intravascular U/S
  • New technique intravascular U/S probe
  • Currently evolving uses include
  • Identification of unstable plaques in CAD
  • Diagnostic and therapeutic use in AD
  • 3-D imaging of aorta surrounding structures
  • Guidance of intra-vascular stent placement less
    invasive procedure than classic surgery
  • Fenestration of intimal flap
  • Not available at most centers at this time

Chavan et al. Circulation 96 2124-2127. 1997
43
(No Transcript)
44
IVUS Aortic Dissection
45
So what test do I order 1st?
  • Moore et al CT is initial test of choice
    followed by TEE to clarify Dx or better delineate
    surrounding anatomy AR
  • Moore et al. Am J Card. 891235-1238. 2002
  • In Calgary, TEE is considered highly accurate and
    available, and should be considered a 1st line
    test
  • Peter Giannacarro

46
Can we predict outcomes?
  • Pulse deficit is independent predictor of 5-day
    mortality RR 2.73, 95 CI 1.7-4.4
  • Stat sig trend of increasing mortality with
    increasing number of pulse deficits
  • Bosssone et al. Am J Card 89 851-855. 2002
  • Mortality predictors
  • Age gt 70 (OR 1.7, 95 CI 1.05-2.77)
  • Abrupt onset CP (OR 2.6, 95 CI 1.22-5.54)
  • Hypotension/shock/tamponade (OR 2.97, 95 CI
    1.25-3.29)
  • ARF (OR 1.77 95 CI 1.80-12.6)
  • Pulse deficit (OR 2.03 95 CI 1.25-3.29)
  • Abnormal ECG (OR 1.77 95 CI 1.06-2.95)
  • Rajendra et al. Circulation. 105 200-206. 2002

47
Management
  • ABCs and then 2 basic principles
  • Control the slope of pulse wave (dP/dT)
  • 1st control your HR, then lower the pressure
  • Surgery if indicated
  • All Type A dissections need urgent OR
  • Controversies New Ideas
  • Surgery for Type B dissections
  • Intravascular repair

48
Medical Tx
  • Control HR
  • IV BBs aim for HR 60-80 bpm
  • Esmolol 500 mcg/kg bolus, then titrate infusion
    50-200 mcg/kg/min
  • Metoprolol 5 mg IVP q5min
  • Propranolol 1mg IVP q5min

49
Medical Tx
  • Control BP
  • aim for BP 100-120 mmHg sys or min BP reqd to
    maintain end-organ perfusion
  • Nitroprusside 0.5 mcg/kg/min titrate up prn
  • Monotherapy
  • Labetalol 20 mg IVP, then 20-80 mg q5-10 min
    until in target HR, then 1-2 mg/hr

50
Surgical Tx
  • Indicated for
  • All Type A dissections
  • Type B w/ complications
  • Aortic rupture
  • Severe distal ischemia
  • Refractory HTN
  • Progressive dissection despite Tx
  • Intractable pain
  • Mortality for Type A repair is 7-12
  • Co-morbidities increase mortality
  • 5 yr survival is 77 Type A 88 Type B

51
Why not operate on all?
  • Medical Tx of Type B has 20 mortality
  • Surgical Tx of Type B has 10-15 mortality, and
    3.5-36 risk of paraplegia
  • This may be changing with advent of endovascular
    repair, fenestration procedures, and IVUS

52
AAA
53
AAA some facts
  • Incidence rising 2 gt65 yo
  • 9 men for every 1 female
  • Most have no antecedent Sx
  • 50-80 mortality rate
  • Misdiagnosed in 30-60 of cases

54
Definitions
  • Aneurysm irreversible localized dilatation of
    an artery to gt 1.5 original diameter (3cm in abd
    aorta)
  • Types of aneurysms
  • True involves intima, media, and adventitia
  • Pseudoaneurysm only intact bulging layer is
    adventita
  • Inflammatory aneurysm surrounding fibrosis and
    adhesions

55
(No Transcript)
56
Pseudoaneurysm
  • Damged intima media
  • Adventitia prevents rupture

57
Anatomy
  1. Aorta
  2. Inf phrenic
  3. R hepatic
  4. Common hepatic
  5. Gastroduodenal
  6. Inf pancreatico-duodenal
  7. L common iliac
  8. L renal
  9. Splenic
  10. L gastric

58
Risk Factors for AAA
  • Age 50-70
  • Male (91)
  • White
  • Atherosclerosis
  • HTN
  • Smoking
  • Family Hx
  • Loss of elastin / CTDs (Marfans)

59
Clinical presentation
  • Unruptured vs. Ruptured
  • Unruptured
  • Vague abd pain / back pain / pulsations /
    fullness
  • SMA syndrome (wt loss, vomiting)
  • Renal colic, radicular Sx, embolic phenomena
  • Ruptured
  • Classic abd pain, pulsatile mass, hypotension
  • Atypical
  • Back or flank pain hematuria
  • LLQ pain GI bleeding
  • Sx of high-output failure

60
Physical Findings
  • Pulsatile abd mass
  • Palpate each sid of aorta if gt2.5 cm w/u
  • PPV 43
  • Other findings neither sensitive or specific

61
How do to Diagnose AAA
  • Clinical suspicion
  • Diagnostic imaging
  • Abd U/S
  • CT abd
  • Angiography
  • MRI
  • What test, when, and for whom?

62
Plain Films
  • Initial screening
  • Findings in 60-75
  • Calcified wall
  • Paravertebral soft tissue mass
  • Loss of psoas shadow
  • Loss of renal silhouette
  • Erosion of vertebral bodies
  • Negative study does NOT exclude Dx

63
Ultrasound
  • Test of choice, esp in unstable pts
  • Advantages
  • 100 sensitive specific for AAA
  • Rapid (5 min vs. 80 min for CT)
  • can be done at bedside
  • non-invasive
  • Disadvantages
  • Poor at identifying rupture
  • Technically difficult in obesity / bowel gas

64
AAA Ultrasound
65
Computed Tomography
  • 100 sensitive specific for AAA
  • Advantages
  • Able to detect ruptures
  • Obesity bowel gas dont limit study
  • Surrounding anatomy
  • Disadvantages
  • Unstable pts
  • Time
  • IV contrast (can do without)
  • Not 100 sensitive for rupture

66
CT Ruptured AAA
  • The CT scan done with of oral and intravenously
    contrast demonstrates opacification of the aorta
    as well as inferior vena cava
  • The arrow head points to the presence of the
    retroperitoneal hematoma, extending into the
    adjacent paraspinal retroperitoneal tissues

67
CT Ruptured AAA
68
Angiography
  • NOT a ED screening tool
  • Tends to underestimate AAA size
  • May aid in planning of surgery (e.g. renal a.
    stenosis)
  • Helical CT can produce 3-D images may replace
    angiography

69
Angiography
70
MRI
  • Not useful in acute setting
  • Excellent anatomical delineation
  • Used primarily prior to elective repair

71
MRI
72
ED Management
  • Depends on context
  • Incidental Dx of AAA
  • Ruptured AAA in stable pt
  • Unstable pt with ruptured AAA
  • Basic principles
  • ABCs
  • Surgical referral for all
  • Elective surgery has 5 mortality
  • Emergent surgery in non-ruptured AAA 25
    mortality
  • Emergent surgery for RAAA 50 mortality
  • Controversies
  • Role of volume resuscitation

73
Fluid Resuscitation
  • Evidence in penetrating trauma for forgoing
    aggressive volume resusitation
  • Bickell et al. N Eng J Med 1994 (331) 1105-1109
  • Fluids can cause dilutional coagulopathy
  • Ø studies compare ED resus strategies in AAA
  • Recent Cochrane Review no evidence to support
    any specific fluid resus strategy in setting of
    traumatic hypovolemic shock
  • Kwan et al. Coch Data Sys Rev. 2002
  • Recommendations are to aim for min BP necessary
    to maintain end-organ perfusion use blood
    products early

74
Natural Hx
  • Formation ? enlargement ? rupture ? DEATH
  • How can we intervene?
  • Primary prevention
  • Early management observation
  • Elective surgery
  • Emergency surgery

75
Risk of Rupture
  • Risk factors
  • Size of AAA
  • COPD
  • HTN
  • smoking
  • What is the risk of rupture?
  • lt4 cm 1-1.2
  • 4-5 cm 1-3
  • One study suggests surgeons estimate risk of
    rupture gt2x published risk
  • Lederle. Arch Intern Med 156 1007-009. 1996

76
Current Surgical Indications
  • All symptomatic aneurysms
  • All saccular aneurysms
  • Poor risk pt w/ AAA gt6 cm
  • Good risk pt w/ AAA gt5 cm
  • Young, good risk pt w/ AAA 4-5 cm
  • Sternbergh et al. Surg Clin NA 78 827-834. 1998

77
Elective repair of small AAAs
  • 5 yr survival 76 vs 30 for emergent
  • 2 recent RCTs suggest no survival benefit from
    immediate surgery for AAAs 4-5.4 cm
  • RR 1.21 95 CI 0.95-1.54
  • Lederle et al. N Eng J Med 346 1437-44. 2002
  • RR 0.94 95 CI 0.75-1.17
  • UK Small Aneurysm Trial Participants. Lancet 352
    1649-55. 1998

78
AAA Repair
79
AAA Repair
80
AAA Repair
81
AAA Repair
82
Traditional vs Endovascular
  • Endovascular repair advantages
  • Less invasive
  • Decd blood loss, procedure times, ICU stays,
    hospitalization time, and recovery time
  • Decd morbidity but not mortality
  • Disadvantages
  • Expense, limited long-term experience but may be
    less durable than conventional repair
  • Utility
  • Clear morbidity advantage in elderly, high risk
    pts demonstrated in recent observational study
  • Sicard et al. Ann Surg 234 427-37. 2001
  • No good evidence to support use in small AAAs or
    younger pts
  • Brewster. Surgery 131 363-7. 2002

83
Late complications
  • Graft infection
  • Early or late (up to years after)
  • 30-50 mortality
  • Staphylococcus epidermidis
  • Present w/ sepsis /- AEF
  • Tx is abx, graft excision, bypass
  • Aorto-enteric fistula (AEF)
  • Can form anywhere (usually duodenum)
  • Acute or chronic GIB
  • Tx is graft replacement

84
The End
  • Questions?

85
Question 1
  • 1. Preexisting conditions associated with an
    increased risk of aortic dissection include which
    of the following?
  • A. Coarctation of the aorta
  • B. Congenital heart disease
  • C. Marfan syndrome
  • D. Pregnancy
  • E. All of the above

E
86
Question 1 Short Answer
  • Dissection is the most common and the most lethal
    catastrophe involving the aorta. Aortic
    dissection occurs two to three times more
    frequently in males than in females, and there
    may be a higher incidence in blacks. Although
    aortic dissection has been reported in patients
    as young as 14 months and as old as 100 years,
    the majority of cases occur in patients between
    50 and 70 years of age. Aortic dissection is
    relatively rare before age 40, except in
    association with specific predisposing syndromes,
    such as Marfan syndrome, Ehlers-Danlos syndrome,
    congenital heart disease, familial incidence,
    pregnancy, coarctation of the aorta, Turner's
    syndrome, and trauma. The type of trauma that is
    usually associated with aortic dissection is
    iatrogenic, such as cardiac surgery and cardiac
    catheterization. The incidence of aortic
    dissection is nine times higher in patients with
    a bicuspid valve, compared with a tricuspid
    aortic valve. Aortic dissection occurs more often
    in patients with a history of coarctation.

87
Question 2
  • 2. Aortic dissection occurs in which layer of the
    aortic wall?
  • A. Adventitia
  • B. External elastic lamina
  • C. Intima
  • D. Media
  • E. Any layer

D
88
Question 3
  • 3. Regarding the Stanford classification of
    aortic dissections, which of the following
    statements is true?
  • A. The majority of patients have Type B
    dissections.
  • B. Patients with Type B dissections tend to be
    older, heavy smokers with chronic lung disease,
    generalized atherosclerosis, and/or hypertension.
  • C. Type A dissections are less common and are not
    associated with high levels of mortality.
  • D. Type A dissections involve the distal aorta.
  • E. The Stanford classification is based on the
    involvement of the descending aorta.

D
89
Question 4
  • 4. Regarding clinical features of aortic
    dissections, which of the following statements is
    not true?
  • A. Aortic regurgitation occurs in about 50 of
    patients with Type A dissection
  • B. In about 20 of patients, neurologic deficit
    is the presenting manifestation.
  • C. Pain is the most common presenting complaint.
  • D. Pulse deficit, a unilaterally weakened or
    absent pulse, occurs in almost 50 of patients
    with proximal dissections.
  • E. The most common neurologic abnormality is
    ischemic paraparesis.
  • F. Syncope, while rare, can be the sole
    presenting symptom.

E
90
Question 5
  • 5. A 66-year-old white male with a history of
    hypertension and a known patent foramen ovale has
    a sudden onset of ripping chest pain that
    radiates to his back, a blood pressure of
    210/120, and a heart rate of 110. Regarding his
    initial treatment, which of the following would
    not be a wise choice?
  • A. Labetalol
  • B. Nitroprusside alone
  • C. Esmolol drip followed by nitroprusside
  • D. Intravenous normal saline

B
91
Question 6
  • 6. Which of the following patients with an acute
    dissection requires immediate surgery?
  • A. A 40-year-old pregnant female with a Type A
    dissection
  • B. A 68-year-old black male with a progressive
    stroke
  • C. A 77-year-old hypertensive white male with a
    Type B dissection
  • D. A 56-year-old Hispanic male with elevated
    cardiac enzymes and a Type IIIA dissection
  • E. None of the above

A
92
Question 7
  • 7. Which of the following statements regarding
    laboratory and radiographic evaluation in the
    work-up of aortic dissection is true?
  • A. Cardiac enzymes are usually elevated.
  • B. Chest x-rays will be abnormal in 80 to 90 of
    cases.
  • C. CT scanning requires arterial catheterization
    for delivery of contrast dye.
  • D. Aortography is no longer the gold standard.
  • E. Transthoracic echocardiography has a
    sensitivity approaching 96

B
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