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					ANEURYSMS &
DISSECTIONS

       NAJEEB TAKI
         EM/IM 2
        3/2/2011
         LEARNING OBJECTIVES
Basic anatomy of a vessel
Definitions of Aneurysms and Dissections
Causes, including risk factors
Clinical presentations
Imaging modalities
Treatment
        ANEURYSMS - DEFINITION
Dilatation of an artery > 1.5 times its normal
 diameter
Three Types:
   True aneurysms
      Involves all layers of the vessel wall
   Pseudo aneurysm
      Involves part of the vessel wall and fibrous tissue
      Usually due to trauma
   Mycotic aneurysm
      Direct extension of an infection leading to aneurysm
      Mainly occur in the immunosuppressed
    EPIDEMIOLOGY & RISK FACTORS
   Majority of cases are Abdominal (AAA)
       > 3.0 cm is considered abnormal
       Most common are between infrarenal and inferior
        mesenteric arteries
   60 or older, men 4 – 5x > women
   Major Risk Factors
       Atherosclerosis > Smoking > Age > Family Hx (4.3
        fold increase) > HTN
   Collagen Elastic Disorders:
       Marfan Syndrome, Ehlers Danlos Syndrome
                PATHOPHYSIOLOGY
   Breakdown of collagen and elastin leads to
    thinning of media in wall
   Increased dilation → Increased wall force
       Laplace Law: Wall Tension = Pressure x Radius
   Increased Dilation → Decreased Tensile
    Strength
   Stress > Tensile Strength → Rupture
   Rupture risk related to Size of Dilation
       > 5 cm should be surgically repaired
       0.25 cm to 0.5 cm/yr increase in dilation
       CLINICAL FEATURES




UNRUPTURED         RUPTURED
→ Variable         → More Clinical
Clinical Sx        Sx
→ Generally        → Increased
Stable             Mortality
    UNRUPTURED SIGNS & SYMPTOMS
   No prevalence of symptoms
   Commonly present with abdominal, back/flank pain
       Pain is dull, gradual onset, vague. If acute or severe, may be
        sign of imminent or actual rupture.
       Can be “throbbing” or colicky in nature
   Most are found incidentally on imaging modalities
   Most consistent physical finding → Abdominal pulsatile
    mass
       3 – 3.9 cm can be palpated 30 – 60% of the time, 4 – 4.9 cm
        50 – 70%, 5 cm or >, 75 – 85%
       Varies if patient is obese or extremely thin
   Abdominal bruit in 5 – 10% of patients
       Nonspecific: stenotic renal, iliac or mesenteric lesions
        RUPTURED SIGNS & SYMPTOMS
   Highly Variable:
       Classic Triad: Pain, hypotension, pulsatile mass
            May have one or two components
   Pain is usually severe, sharp, constant
       Described as “ripping” or “tearing”
       Areas include abdominal, flank or back pain; radiates to chest,
        thigh, scrotum, inguinal area
   10% may present with syncope as initial complaint
   Unexplained Upper or Lower GI bleeding secondary to
    Aortoenteric fistula
   High output cardiac failure, decreased arterial blood flow,
    increased central venous pooling secondary to Aortovenous
    fistula
   Periumbilical ecchymosis (Cullen Sign) or Flank ecchymosis
    (Grey Tuner Sign)
             DIFFERENTIAL DIAGNOSIS
   Renal Colic
   “Acute Abdomen”
       Pancreatitis
       Intestinal Ischemia
       Diverticulitis
       Cholecystitis
       Appendicitis
       Perforated Viscus
       Bowel Obstruction
   Musculoskeletal Back Pain
   Acute MI (epigastric pain and hypotension)
   Consider in pts who are middle aged/elderly and have
    triad
                               IMAGING
   X-ray:
       Not specific: Can be helpful for other diagnosis
       May find calcified, curvilinear aorta or paravertebral mass
                Present in 65% of patients
   Ultrasound:
       > 90% sensitivity
       Operator dependent, cannot determine if AAA is
        ruptured or if patient has retroperitoneal bleed
   CT Scan:
       Virtually 100% accurate in detecting AAA rupture
       Better pictures, can tell if retroperitoneal bleed, can tell
        about other disorders
       Set backs: Increased time; falsely reassuring with
        missing hemorrhage
                           TREATMENT
   Unstable until Aorta is cross-clamped or endovascularly
    repaired
       ½ of ruptured aorta patients die when they reach the
        operating room
   ABCs
       2 large bore IVs
       Large transfusion requirement
   Fluid Resuscitation:
       Slightly hypotensive vs. normotensive
       Controversial: Clotting of rupture and slowing of bleeding vs.
        Dilution of thrombogenic products
   Emergent Surgical Consult
   Diagnostic testing should not delay operative treatment
                  DISSECTION
• Definition:
  • Longitudinal cleavage of media due to dissecting
    column of blood
• Incidence 2.6 – 3.5/100,000 a year
• Age range between 60 – 80 years
• Mortality is 1 – 5/100,000 a year
  • 22% of cases undiagnosed prior to death
• Males have a higher predilection than females
  • Females are generally older (67 years)
  • Uncommon below age 40 unless has familial or
    genetic predilection
          PREDISPOSING FACTORS
• Most important predisposing factor is HTN
  • Atherosclerosis is secondary
• Under the age of 40:
  • Collagen Disorders: Ehlers Danlos, Marfan Syndrome,
    Bicuspid Aortic Valve, Aortic Coarctation, Turner’s Syndrome
  • Trauma
  • High intensity weight lifting
  • Crack/Cocaine use
• Other Causes:
  • CABG
  • Previous Aneurysm
  • Valve replacement
            PATHOPHYSIOLOGY
• As heart beats, causes aorta to flex near aortic
  valve and at descending area  repeated stress
  injury
• Medial Degeneration worsened by hypertensive
  forces or by genetic predisposition  Tear in
  intima  medial hematoma
• Alternative theory suggests hydrodynamic
  forces causes rupture of vasa vasorum and
  medial hematoma
        PATHOPHYSIOLOGY
Medial hematoma propagates  False Lumen




 Re-tear through      Ruptures Adventitia
 Intima =
 “Spontaneous Cure”

                         Aortic Rupture
STANFORD/DAILY CLASSIFICATION
DEBAKEY CLASSIFICATION
          DISSECTION VARIANTS
• Intramural Hemorrhage:
  • Contained hematoma without intimal tear secondary
    to vasa vasorum rupture
• Penetrating atherosclerotic ulcers
  • Ulceration of aorta secondary to atherosclerosis with
    mainly aortic aneurysm formation but can lead to
    dissection or even rupture
    CLINICAL FEATURES - HISTORY
• Pain is #1 complaint (> 90% of patients)
  • Sharp, “tearing” or “ripping”, acute in onset
  • Anterior chest pain = aortic arch
  • Post. chest pain between shoulder blades =
    descending aorta
  • Radiates to thorax or abdomen
• ~ 10% present with syncope
  • Worse outcome, more associated with cardiac
    tamponade and stroke
• Neurological Sx such as focal weakness, altered
  mental status occur in up to ~ 20% of patients
               ASCENDING AORTA SX
• Acute Aortic Insufficiency
   • Decrescendo diastolic murmur along with acute hypotension and/or heart
     failure
• Myocardial Ischemia
   • Coronary Occlusion  affects Right Coronary Artery mainly with either
     complete heart block or inferior MI
• Cardiac tamponade
• Hemothorax secondary to exsangunation
• Horner’s Syndrome with compression on superior cervical
  sympathetic ganglion
• Vocal cord paralysis with compression of recurrent laryngeal
  nerve
• Neurologic deficits secondary to carotid artery involvement
         DESCENDING AORTA SX
• Peripheral Neuropathy secondary to ischemic
  nerve damage
• Spinal Cord Ischemia
• Migrating pain
• Hypertension
• End organ ischemia
  • Spleen
  • Kidneys
  • Peripheral limbs
         PHYSICAL EXAMINATION
• Highly variable depending on where dissection
  is located
• More likely to be hypertensive, unless
  exsanguinating
• Aortic Insufficiency murmur
• Pulse deficits
• Tachycardic
         DIFFERENTIAL DIAGNOSIS
• Myocardial ischemia due to an acute coronary syndrome
  with or without ST segment elevation
• Pericarditis
• Pulmonary embolus
• Aortic regurgitation without dissection
• Aortic aneurysm without dissection
• Musculoskeletal pain
• Mediastinal tumors
• Pleuritis
• Cholecystitis
• Atherosclerotic or cholesterol embolism
• Peptic ulcer disease or perforating ulcer
• Acute pancreatitis
                     DIAGNOSTICS
• Lab tests:
  • Not diagnostic in ruling in or out a dissection
  • May help distinguish between other causes
• EKG:
  • Useful in excluding MI, however 15% of pts, have MI
    secondary to Dissection
  • Nonspecific, will show Left vent. hypertrophy, nonspecific ST
    changes
• X-Ray:
  • Abnormal in 80 – 90% of patients
  • Mediastinal Widening, double density of aorta (false and true
    lumen), change in caliber of ascending or descending aorta,
    obliteration of aortic knob, displacement of trachea or
    esophagus
  • ~ 12% of patients will have normal X ray
              DIAGNOSTICS (CONT.)
• Echo:
  • TTE insensitive for dissection secondary to poor visualization
    of aortic arch
     • Good for ruling out cardiac tamponade, pericardial effusion or valve
       disorder
  • TEE very good for detecting dissection. Rapid and can be
    done with light sedation.
     • Operator dependant
• CT scan:
  • Diagnostic test of choice
  • Can distinguish between variants of dissection
  • Improved detail over echo
 Sensitivities and Specificities of Imaging
Modalities for Diagnosing Aortic Dissection
                       HELICAL
 TEST              TEE                         MRI
                       CT
 Sensitivity (%) 98         100                98



 Specificity (%) 95         98                 98



 From Shiga T, Wajima Z, Apfel CC, et al: Diagnostic
 accuracy of transesophageal echocardiography, helical
 computed tomography, and magnetic resonance imaging
 for suspected thoracic aortic dissection: Systematic
 review and meta-analysis. Arch Intern Med 166:1350–
 1356, 2006.)
                    TREATMENT
• ABCs
• Treat Pain
  • Opiods help in decreasing sympathetic tone
• Hypotensive patient:
  •   More likely has ascending dissection
  •   Fluid resuscitation
  •   Emergent OR transfer
  •   Blood pressure measurement in all four limbs to rule
      out pseudohypotension (intimal flap which blocks
      flow through artery in affected limb)
     TREATMENT - HYPERTENSIVE
• Goals:
   • Decrease B.P. to 100 – 120 mmHg with heart rate to 60 bpm
   • Decrease rise in arterial pulse leading to a decrease in shearing forces
• Beta-blockers:
   • Esmolol: 0.1 – 0.5mg/kg IV in one minute then infusion of 0.025 to
     0.2mg/kg/min
   • Metoprolol: 5mg up to 15mg IV initial bolus then 2 to 5mg infusion/hr.
   • Labetalol: 10 to 20 mg IV initial with repeat of 20 to 40mg q10 minutes
     until effect or max. dose of 300mg.
• Calcium Channel Blockers:
   • Limited use.
   • May be used if contra-indicated with Beta-blockers
    TREATMENT - HYPERTENSIVE
• Vasodilators:
  • Used in conjunction with Beta-blockade
  • Start once Beta-blockers have taken effect
  • Nitroprusside: Initial infusion of 0.3
    microgram/kg/min IV
  • Nitroglycerin: not as good as nitroprusside.
                                                       REFERENCES
Vessel Wall Anatomy:

http://www.lab.anhb.uwa.edu.au/mb140/corepages/vascular/vascular.htm

Aorta Picture:

http://www.tommyroshek.com/images/index.html

Types of Aneurysms:

http://www.sjmedgroup.org/pages/HL_CARD_abdominal-aortic-aneurysm

Heart Picture:

http://www.heartrehabilitationexercise.com/wp-content/uploads/2010/02/BHF2-946x1024.jpg

Stanford Criteria Picture:

http://www.mayoclinic.org/images/acute-aortic-dissection-2col.jpg

Widened Mediastinum Xray:

http://knol.google.com/k/-/-/ZGdKu25p/lKPiNQ/widemediastinum.jpg

EKG:

http://heart.bmj.com/content/93/10/1225/F1.large.jpg

TEE:

http://cmbi.bjmu.edu.cn/uptodate/pictures/card_pix/ad_i_tee.gif

TEE 2:

http://cmbi.bjmu.edu.cn/uptodate/pictures/card_pix/ad_c_i.gif

Debakey Picture:

http://images.radiopaedia.org/images/451/6a7cff8fae470ed776426a2bc3d39f.jpg

http://images.radiopaedia.org/images/927/5b33830d2c371ff479c5b7082c0fe1.jpg

http://images.radiopaedia.org/images/587/6fd2c5081df13d6ae300b54a20e783.jpg
                                           REFERENCES
Widened Mediastinum Xray:

http://knol.google.com/k/-/-/ZGdKu25p/lKPiNQ/widemediastinum.jpg

EKG:

http://heart.bmj.com/content/93/10/1225/F1.large.jpg

TEE:

http://cmbi.bjmu.edu.cn/uptodate/pictures/card_pix/ad_i_tee.gif

TEE 2:

http://cmbi.bjmu.edu.cn/uptodate/pictures/card_pix/ad_c_i.gif

All pictures from images.google.com and are of their respective copyrights. No infringement intended.
                                              REFERENCES
Materials:

1)Prince Louise A, Johnson Gary A, "Chapter 63. Aneurysms of the Aorta and Major Arteries" (Chapter). Tintinalli JE, Stapczynski JS,
     Cline DM, Ma OJ, Cydulka RK, Meckler GD: Tintinalli's Emergency Medicine: A Comprehensive Study Guide, 7e:
     http://www.accessmedicine.com/content.aspx?aID=6359748.

2) Marx et. al. Chapter 84 Abdominal Aortic Aneurysm. Rosen's Emergency Medicine 7th Editionfrom MD Consult
    http://intranetprod.wpahs.org:2252/books/page.do?eid=4-u1.0-B978-0-323-05472-0..00084-0--s0095&isbn=978-0-323-05472-
    0&type=bookPage&sectionEid=4-u1.0-B978-0-323-05472-0..00084-0--s0100&uniqId=236296679-9#4-u1.0-B978-0-323-05472-
    0..00084-0--s0100

3) Mohler, E.; Fairman, R. Epidemiology, Clinical Features, and Diagnosis of Abdominal Aortic Aneurysm. Uptodate. 2010.
    http://intranetprod.wpahs.org:2053/contents/epidemiology-clinical-features-and-diagnosis-of-abdominal-aortic-
    aneurysm?source=search_result&selectedTitle=5%7E150#H12

4) Woo, Y. Mohler, E. Clinical Features and Diagnosis of Thoracic Aortic Aneurysm. Uptodate. 2010.
    http://intranetprod.wpahs.org:2053/contents/clinical-features-and-diagnosis-of-thoracic-aortic-
    aneurysm?source=search_result&selectedTitle=2%7E31

5) Mohler, E.; Fairman, R. Natural History and Management of Abdominal Aortic Aneurysm. Uptodate. 2010.
    http://intranetprod.wpahs.org:2053/contents/natural-history-and-management-of-abdominal-aortic-
    aneurysm?source=search_result&selectedTitle=1%7E104

6) Manning, W. Clinical Manifestations and Diagnosis of Aortic Dissection. uptodate. 2010.
    http://intranetprod.wpahs.org:2053/contents/clinical-manifestations-and-diagnosis-of-aortic-
    dissection?source=search_result&selectedTitle=1%7E117

7) Manning, W. Management of Aortic Dissection. Uptodate. 2010. http://intranetprod.wpahs.org:2053/contents/management-of-aortic-
    dissection?source=search_result&selectedTitle=2%7E117

8) Johnson Gary A, Prince Louise A, "Chapter 62. Aortic Dissection and Related Aortic Syndromes" (Chapter). Tintinalli JE,
     Stapczynski JS, Cline DM, Ma OJ, Cydulka RK, Meckler GD: Tintinalli's Emergency Medicine: A Comprehensive Study Guide,
     7e: http://www.accessmedicine.com/content.aspx?aID=6359670

9) Marx et. al. Chapter 83 Aortic Dissection. Rosen's Emergency Medicine 7th Edition from MD Consult.
    http://intranetprod.wpahs.org:2252/books/page.do?eid=4-u1.0-B978-0-323-05472-0..00083-9--s0055&isbn=978-0-323-05472-
    0&type=bookPage&sectionEid=4-u1.0-B978-0-323-05472-0..00083-9--s0055&uniqId=236333558-9#4-u1.0-B978-0-323-05472-
    0..00083-9--s0055

				
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