Abdominal aortic aneurysm: Difference between revisions
 
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== Background ==
==Background==
 
[[File:Aorta segments.jpg|thumb|Aortic sebments.]]
[[File:Aorta branches.jpg|thumb|Branches of the aorta.]]
[[File:AneurysmAortaWithArrows.jpg|thumb|CT reconstruction image of an abdominal aortic aneurysm (white arrows).]]
*Different types
**Fusiform (~92%)- Bulging or ballooning of all sides of the aorta
**Saccular (~5%)- Bulging or ballooning of only one side of the aorta
**Mycotic (less than 3%)- Caused by an infection of the vessel wall
***More common in Asian countries, can be as much as 13%
***May be bacterial, viral, or fungal
***May be a complication of infectious endocarditis
***Increased risk of rupture
*Infrarenal diameter >3cm or >50% increase in size of diameter
*Infrarenal diameter >3cm or >50% increase in size of diameter
**85% of cases are infrarenal <ref name="NJM"></ref>
**Mean growth rate is about 0.2-0.3 cm/yr
*Rupture Risk
*Rupture Risk
**<4cm: low risk for rupture
**<4cm: low risk for rupture
**4-5cm: 5 year risk 3-12%
**4-5cm: 5 year risk 3-12%
**>5cm: 25-41%
**>5cm: 25-41%
**Rupture poss at any size, most commonly >5cm
**Rupture possible at any size, most commonly >5cm
**Mortality with rupture: 85-90% <ref name="NJM">Kent, K. Abdominal Aortic Aneurysms. The New England Journal of Medicine. 2014; 371:2101-8. DOI: 10.1056/NEJMcp1401430 </ref>


===Risk Factors===
===Risk Factors===
*Gender (male to female ratio 4:1)
*Smoking
**Risk factor most strongly associated with AAA
**Also promotes the rate of aneurysm growth
**Direct relationship between risk and number of smoking years
*Age (prevalence is negligible in age <50yrs)
*Family history
*Hypertension
*Hyperlipidemia
*Fluoroquinolone use <ref>P. Wendling for Medscape.  FDA Warns of Aortic Aneurysm Risk with Fluoroquinolones.  https://www.medscape.com/viewarticle/906867.  Accessed 12/26/2018.</ref>
==Clinical Features==
*Classic triad (only 50% of cases) is [[abdominal pain|pain]] + [[hypotension]] + pulsatile mass
**Pain often described as sudden, severe, radiating to back, ripping quality
*[[Syncope]] (10%)
*Signs of [[Retroperitoneal hemorrhage]]
*Massive [[GI bleed]] from [[aortoenteric fistula]]
*Pain + AAA = rupture until proven otherwise
*Acute abdomen + hypotension = possible rupture
*Gross [[hematuria]] can be caused by an aortocaval fistula (very rare)
*Unruptured aneurysms are frequently asymptomatic
==Differential Diagnosis==
{{Abdominal Pain DDX Diffuse}}


#Age
{{Lower back pain DDX}}
##Prevalence is negligible in age < 50 yrs
#Smoking
##Risk factor most strongly assoc with AAA
##Also promotes the rate of aneurysm growth
#Family history
#HTN


== Diagnosis ==
==Evaluation==
[[File:AAA.png|thumb|AAA]]
[[File:AAA_with_Thrombus.gif|thumbnail|Ultrasound of AAA with Thrombus (click to view).<ref>http://www.thepocusatlas.com/aorta-1/</ref>]]
[[File:AneursymCTMark.png|thumb|Abdominal aortic aneurysm seen on CT with a small area of remaining blood flow (white).]]
[[File:Sagital aaa.jpg|thumb|Sagital reconstruction of aortic aneurysm]]
*'''Labs'''
**Coagulation studies
**Creatinine
**Urinalysis
**CBC
**Type and cross-match blood


*May be asymptomatic or abdominal/back pain
*Pain + AAA = rupture until proven otherwise
*Acute abdomen + BP = possible rupture


== Workup ==
*'''Imaging'''
**[[Aortic ultrasound|Ultrasound]]
***~99% sensitive/98% specific for increased diameter<ref>Rubano E, Mehta N, Caputo W, Paladino L, Sinert R. Systematic review: emergency department bedside ultrasonography for diagnosing suspected abdominal aortic aneurysm. Acad Emerg Med. 2013;20(2):128-138. doi:10.1111/acem.12080 </ref>
***Cannot reliably visualize rupture (only 4% sensitive)<ref>Rubano E, Mehta N, Caputo W, Paladino L, Sinert R. Systematic review: emergency department bedside ultrasonography for diagnosing suspected abdominal aortic aneurysm. Acad Emerg Med. 2013;20(2):128-138. doi:10.1111/acem.12080 </ref>
**CT
***~100% sensitive for increased diameter and rupture
***IV contrast is preferred but not essential
 
==Management==
===Rupture===
[[File:RupturedAAA.png|thumb|Ruptured AAA with an open arrow marking the aneurysm and the closed arrow marking the free blood in the abdomen.]]
*Do not waste time in ED trying to "stabilize" patient
*Immediate surgery consultation/ go to OR
*Crossmatch 6 units of pRBC
*Pain control (avoid hypotension)
*Antihypertensives (use with caution, goal SBP 110-120 mmHg or MAP 70-80)<ref>Reed, K. Aortic Emergencies, EB Medicine. 2006.</ref>
**[[Labetalol]]: 20mg IV, then 40-80mg IV q10 min (max 300mg)
**[[Esmolol]]: Bolus 500 mcg/kg, then 50-200 mcg/kg/min
**[[Nitroprusside]]: 0.3 - 0.5 mcg/kg/min, titrate to max 10 mcg/kg/min
*Controversial
**Too little (ischemia), too much (increased bleeding)
***Consider allowing for permissive hypotension (SBP 70-90) in conscious patient<ref>Chaikof EL, Dalman RL, Eskandari MK, et al. The Society for Vascular Surgery practice guidelines on the care of patients with an abdominal aortic aneurysm. J Vasc Surg. 2018;67(1):2-77.e2. doi:10.1016/j.jvs.2017.10.044</ref>
**[[Pressors]]
***[[Norepinephrine]] 0.05mcg/kg/min IV; titrate by 0.02mcg/kg/min q5min
***[[Phenylephrine]] 100-180mcg/min; titrate by 25mcg/min q10min
***[[Dopamine]] 5mcg/kg/min; titrate by 5mcg/kg/min q10min


*US (cannot see rupture)
===Asymptomatic===
*CT Noncon (if stable)
*Aneurysm > 5 cm: Prompt (within days) vascular surgery outpatient follow-up appt
**Endovascular (75%) vs open repair
*Aneurysm 3-5 cm: Can likely follow up with PCP/surgeon on non-urgent basis
*Screening frequency:
**3-4 cm diameter: 12 months
**4-5 cm diameter: 6 months
**5-6 cm diameter: 1 month
*Elective Surgery indicated if:
**AAA > 5.5 cm in men <ref name="NJM"></ref>
**AAA > 5 cm in women <ref name="NJM"></ref>
**increase in size > 1 cm/year
**increase in size > 5 mm/6 months


== Treatment ==
==Complications==
*[[Aortoenteric fistula]]
*[[Aortocaval fistula]]
*[[Inflammatory abdominal aortic aneurysm]]
*[[Acute limb ischemia]] - embolism to lower extremities
*Graft infection
*Endoleak


#Rupture
==Disposition==
##-->EMERGENT SURG/Endovasc
*Admit to OR for ruptured or symptomatic AAA
##Do not waste time for stablization --> OR
*May discharge asymptomatic cases with close vascular surgery follow up
##T&C x 6-10U PRBCs, 4U FFP and 4U platelets
**Instruct to return immediately if symptoms manifest (abdominal/back pain, syncope, dizziness, extremity pain)
##Maintain BP high enough to keep asymptomatic end organ (like penetrating tauma)
##Do not lower BP if R/O rupture (chronic ok)
#Asymptomatic
##-->Incidental finding: f/u Vascular


== Source ==
==External Links==
* [https://rebelem.com/rebel-core-cast-49-0-abdominal-aortic-aneurysm-aaa/ REBEL EM - Abdominal Aortic Aneurysm (AAA)]
* [http://www.emdocs.net/the-crashing-abdominal-aortic-aneurysm-patient/  emDocs - The Crashing Abdominal Aortic Aneurysm Patient]


Donaldson, Bessen, H-N, UpToDate
==References==
<references/>


<br/>[[Category:Cards]]
[[Category:Cardiology]]
[[Category:Vascular]]

Latest revision as of 20:23, 13 June 2024

Background

Aortic sebments.
Branches of the aorta.
CT reconstruction image of an abdominal aortic aneurysm (white arrows).
  • Different types
    • Fusiform (~92%)- Bulging or ballooning of all sides of the aorta
    • Saccular (~5%)- Bulging or ballooning of only one side of the aorta
    • Mycotic (less than 3%)- Caused by an infection of the vessel wall
      • More common in Asian countries, can be as much as 13%
      • May be bacterial, viral, or fungal
      • May be a complication of infectious endocarditis
      • Increased risk of rupture
  • Infrarenal diameter >3cm or >50% increase in size of diameter
    • 85% of cases are infrarenal [1]
    • Mean growth rate is about 0.2-0.3 cm/yr
  • Rupture Risk
    • <4cm: low risk for rupture
    • 4-5cm: 5 year risk 3-12%
    • >5cm: 25-41%
    • Rupture possible at any size, most commonly >5cm
    • Mortality with rupture: 85-90% [1]

Risk Factors

  • Gender (male to female ratio 4:1)
  • Smoking
    • Risk factor most strongly associated with AAA
    • Also promotes the rate of aneurysm growth
    • Direct relationship between risk and number of smoking years
  • Age (prevalence is negligible in age <50yrs)
  • Family history
  • Hypertension
  • Hyperlipidemia
  • Fluoroquinolone use [2]

Clinical Features

  • Classic triad (only 50% of cases) is pain + hypotension + pulsatile mass
    • Pain often described as sudden, severe, radiating to back, ripping quality
  • Syncope (10%)
  • Signs of Retroperitoneal hemorrhage
  • Massive GI bleed from aortoenteric fistula
  • Pain + AAA = rupture until proven otherwise
  • Acute abdomen + hypotension = possible rupture
  • Gross hematuria can be caused by an aortocaval fistula (very rare)
  • Unruptured aneurysms are frequently asymptomatic

Differential Diagnosis

Diffuse Abdominal pain

Lower Back Pain

Evaluation

AAA
Ultrasound of AAA with Thrombus (click to view).[3]
Abdominal aortic aneurysm seen on CT with a small area of remaining blood flow (white).
Sagital reconstruction of aortic aneurysm
  • Labs
    • Coagulation studies
    • Creatinine
    • Urinalysis
    • CBC
    • Type and cross-match blood


  • Imaging
    • Ultrasound
      • ~99% sensitive/98% specific for increased diameter[4]
      • Cannot reliably visualize rupture (only 4% sensitive)[5]
    • CT
      • ~100% sensitive for increased diameter and rupture
      • IV contrast is preferred but not essential

Management

Rupture

Ruptured AAA with an open arrow marking the aneurysm and the closed arrow marking the free blood in the abdomen.
  • Do not waste time in ED trying to "stabilize" patient
  • Immediate surgery consultation/ go to OR
  • Crossmatch 6 units of pRBC
  • Pain control (avoid hypotension)
  • Antihypertensives (use with caution, goal SBP 110-120 mmHg or MAP 70-80)[6]
    • Labetalol: 20mg IV, then 40-80mg IV q10 min (max 300mg)
    • Esmolol: Bolus 500 mcg/kg, then 50-200 mcg/kg/min
    • Nitroprusside: 0.3 - 0.5 mcg/kg/min, titrate to max 10 mcg/kg/min
  • Controversial
    • Too little (ischemia), too much (increased bleeding)
      • Consider allowing for permissive hypotension (SBP 70-90) in conscious patient[7]
    • Pressors
      • Norepinephrine 0.05mcg/kg/min IV; titrate by 0.02mcg/kg/min q5min
      • Phenylephrine 100-180mcg/min; titrate by 25mcg/min q10min
      • Dopamine 5mcg/kg/min; titrate by 5mcg/kg/min q10min

Asymptomatic

  • Aneurysm > 5 cm: Prompt (within days) vascular surgery outpatient follow-up appt
    • Endovascular (75%) vs open repair
  • Aneurysm 3-5 cm: Can likely follow up with PCP/surgeon on non-urgent basis
  • Screening frequency:
    • 3-4 cm diameter: 12 months
    • 4-5 cm diameter: 6 months
    • 5-6 cm diameter: 1 month
  • Elective Surgery indicated if:
    • AAA > 5.5 cm in men [1]
    • AAA > 5 cm in women [1]
    • increase in size > 1 cm/year
    • increase in size > 5 mm/6 months

Complications

Disposition

  • Admit to OR for ruptured or symptomatic AAA
  • May discharge asymptomatic cases with close vascular surgery follow up
    • Instruct to return immediately if symptoms manifest (abdominal/back pain, syncope, dizziness, extremity pain)

External Links

References

  1. ↑ 1.0 1.1 1.2 1.3 Kent, K. Abdominal Aortic Aneurysms. The New England Journal of Medicine. 2014; 371:2101-8. DOI: 10.1056/NEJMcp1401430
  2. ↑ P. Wendling for Medscape. FDA Warns of Aortic Aneurysm Risk with Fluoroquinolones. https://www.medscape.com/viewarticle/906867. Accessed 12/26/2018.
  3. ↑ http://www.thepocusatlas.com/aorta-1/
  4. ↑ Rubano E, Mehta N, Caputo W, Paladino L, Sinert R. Systematic review: emergency department bedside ultrasonography for diagnosing suspected abdominal aortic aneurysm. Acad Emerg Med. 2013;20(2):128-138. doi:10.1111/acem.12080
  5. ↑ Rubano E, Mehta N, Caputo W, Paladino L, Sinert R. Systematic review: emergency department bedside ultrasonography for diagnosing suspected abdominal aortic aneurysm. Acad Emerg Med. 2013;20(2):128-138. doi:10.1111/acem.12080
  6. ↑ Reed, K. Aortic Emergencies, EB Medicine. 2006.
  7. ↑ Chaikof EL, Dalman RL, Eskandari MK, et al. The Society for Vascular Surgery practice guidelines on the care of patients with an abdominal aortic aneurysm. J Vasc Surg. 2018;67(1):2-77.e2. doi:10.1016/j.jvs.2017.10.044
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