PowerPoint Presentation - Calgary Emergency Medicine by dfhdhdhdhjr

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									Aortic Emergencies

    Moritz Haager
    Sept 19, 2002
              Objectives
• Define aortic dissection + AAA, and why
  its important
• Review pathophysiology and classification
• Discuss diagnostic modalities
• Discuss management options
             What is Dissection?
• Aortic
  dissection 
  dissecting aortic
  aneurysm
• “longitudinal
  cleavage of the
  aortic media
  created by a
  dissecting
  column of
  blood”Rosen’s Emergency
  Medicine
                   Relevance
•   Underreported
•   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 EP’s suspect AD in
    <50% 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
              Sad but true..
• 42 yo M presents c/o pain in R groin + leg
• Also atypical CP/back pain preceding
• Sniffed coke ~2 hrs ago + popped viagra ~1 hr
  ago at a “sex party”
• PMHx: HTN, smoker
• O/E: 92/ 160/100 /16; pale, diaphoretic, unwell
  looking; 2/6 SEM at apex, clear lungs, soft non-
  tender belly w/ Ø masses, R foot/ leg cool w/ Ø
  femoral, popliteal or tibial pulses
• ECG: isolated ventricular beats
• B/W: normal except +ve tox for cocaine
• CT: Stanford Type B dissection
• TEE: 3.5 cm intimal tear, Ø AR
                           Famularo et al. J Emerg Med 21(1): 78-9. 2001
                  Pathophysiology
•    Requires 3
     basic features:
    1. Abnormal
       media
    2. Blood entry
       into media
       (intimal tear, or
       vasa vasorum
       rupture)
    3. Pressure
       forces favoring
       propagation
                 Pathophysiology
•       Peripheral complications: expanding hematoma
        dissects into, or compresses branches, or
        fistulizes into adj. structures
    –     Cerebral  CVA, syncope,
    –     Spinal  Neuro deficits
    –     Cardiac  MI, tamponade
    –     Respiratory  Hemoptysis, pleural effusion
    –     GI  Hematemesis, dysphagia, mesenteric
          ischemia
    –     Renal  ARF, HT N
    –     Limbs  Extremity ischemia
• 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)
• Hemopericardium
  and tamponade can
  occur with
  dissection into
  pericardial sac
-Coronary artery involvement in ~1%  presents as MI
-0.1-0.2% of MI’s are complicated by admin of lytics in
setting of AD
            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%)
    –   GI Sx
    –   Resp Sx
• Can be painless in up to 15% (chronic)
                            Moore et al. Am J Card. 89:1235-1238 2002
                            Hals. Emerg Med Reports 2000
          Risk Factors for AD
•   Hypertension (60-90%)
•   Age 50-70 yo
•   Male (3:1)
•   CTD’s (Marfans ~5%, Ehlers-Danlos)
•   Turners, Coarctation, Ebstein’s Anomaly
•   Congenital bi-/tricuspid AV
•   Family Hx or previous dissection
•   Cocaine, metamphetamine
•   Iatrogenic
•   Trauma
                                   Hals. Emerg Med Reports 2000
             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
DeBakey
               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
Classification
          How to diagnose 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
     • > 2 variables or isolated BP / pulse diff  > 83% risk of AD
            » Von Kodolitsch et al. Arch Intern Med. 160: 2977-82. 2000

• Diagnostic modalities
     • ECG, CXR, CT, TEE, Angiogram, MRI
           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
            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
                           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. 89:1235-1238. 2002
                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
              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
                     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
         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
3-D IVUS
  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. 89:1235-1238. 2002

• In Calgary, TEE is considered highly
  accurate and available, and should be
  considered a 1st line test
         » Peter Giannacarro, personal communication
       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 > 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
               Management
• ABC’s and then 2 basic principles:
  – Control 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
                Medical Tx
• Control HR
  – IV BB’s – aim for HR 60-80 bpm
    • Propranolol 1mg IVP q5min
    • Esmolol 500 mcg/kg bolus, then titrate infusion
      50-200 mcg/kg/min
    • Metoprolol 5 mg IVP q5min
    • Diltiazem 20 mg IV bolus, then 5-15 mg/hr if BB
      contraindicated (heart block, asthma, COPD, CHF)
               Medical Tx
• Control BP
    • aim for BP 100-120 mmHg sys or min BP
      req’d 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
                     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
     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.
      New Surgical Methods
• IVUS-guided fenestration of intimal flap
         » Chavan et al. Circulation 96: 2124-2127. 1997

• Intravascular stent placement
  – Cover intimal flap reducing flow to false
    lumen  clotting of false lumen
  – 1.6 hrs vs 8 hrs for conventional Sx
  – One recent series of 70 Type B AD pts tx’d
    w/ stent-grafts reported 92.9% success and
    9.6% all cause mortality at 29 months
         » Palma et al. Ann Thorac Surg 73: 138-42. 2002
           AAA: some facts
•   Incidence rising: 2% >65 yo
•   9 men for every 1 female
•   Most have no antecedent Sx
•   50-80% mortality rate
•   Misdiagnosed in 30-60% of cases
               Definitions
• Aneurysm = irreversible localized
  dilatation of an artery to > 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
           Pseudoaneurysm
• Damged
  intima +
  media
• Adventitia
  prevents
  rupture
     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
Anatomy
         Risk Factors for AAA
•   Age 50-70
•   Male (9:1)
•   White
•   Atherosclerosis
•   HTN
•   Smoking
•   Family Hx
•   Loss of elastin / CTD’s (Marfans)
        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
           Physical Findings
• Pulsatile abd mass
  – Palpate each sid of aorta; if >2.5 cm w/u
  – PPV ~43%
• Other findings neither sensitive or
  specific
      How do to Diagnose AAA
• Clinical suspicion
• Diagnostic imaging
  –   Abd U/S
  –   CT abd
  –   Angiography
  –   MRI
• What test, when, and for whom?
   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
                 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
        Computed Tomography
• 100% sensitive + specific for AAA
• Advantages
  – Able to detect ruptures
  – Obesity + bowel gas don’t limit study
  – Surrounding anatomy
• Disadvantages
  –   Unstable pts
  –   Time
  –   IV contrast (can do without)
  –   Not 100% sensitive for rupture
             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
                   MRI
• Not useful in acute setting
• Excellent anatomical delineation
• Used primarily prior to elective repair
                  ED Management
•       Depends on context:
    –     Incidental Dx of AAA
    –     Ruptured AAA in “stable” pt
    –     Unstable pt with ruptured AAA
•       Basic principles:
    –     ABC’s
    –     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
          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
                Natural Hx
• Formation  enlargement  rupture 
  DEATH
• How can we intervene?
  –   Primary prevention
  –   Early management + observation
  –   Elective surgery
  –   Emergency surgery
              Risk of Rupture
• Risk factors
  –   Size of AAA
  –   COPD
  –   HTN
  –   smoking
• What is the risk of rupture?
  – <4 cm: ~1-1.2%
  – 4-5 cm: 1-3%
• One study suggests surgeons estimate risk of
  rupture >2x published risk
            » Lederle. Arch Intern Med 156: 1007-009. 1996
    Current Surgical Indications
•   All symptomatic aneurysms
•   All saccular aneurysms
•   Poor risk pt w/ AAA >6 cm
•   Good risk pt w/ AAA >5 cm
•   Young, good risk pt w/ AAA 4-5 cm
           » Sternbergh et al. Surg Clin NA 78: 827-834. 1998
 Elective repair of small AAA’s
• 5 yr survival ~76% vs ~30% for emergent
• 2 recent RCT’s suggest no survival
  benefit from immediate surgery for
  AAA’s 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
   Traditional vs Endovascular
• ELG repair advantages:
  – Less invasive
  – Dec’d blood loss, procedure times, ICU stays,
    hospitalization time, and recovery time
  – Dec’d 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 AAA’s or
    younger pts
            » Brewster. Surgery 131: 363-7. 2002
            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
Questions?   1 hour boy!!..all
             you had to do is
             talk for 1 lousy
             hour! I could be
             drunk by now!!

								
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