INDEX

    Aortic Dissection

    Cardiovascular

    Last Updated Sep 15, 2018
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    Context

    • This is a rare event, 3-5/100,000 cases per year but with a high mortality: 22% in type A; 1-2 % increase in mortality for every hour in delay to surgery.
    • Average age is 63: 75% between 40-70 yrs; 65% male; 65-75% history of hypertension.

     

    Two classification schemes

     

    1)  Stanford

    • Type A: Involves ascending aorta +/- descending aorta (60% of dissections).
    • Type B: Involves only the descending aorta.

     

    2)  DeBakey

    • I – Ascending aorta which extends to at least the aortic arch +/- descending aorta.
    • II – Only the ascending aorta.
    • III – Only the descending aorta.

    Diagnostic Process

    • American Heart Association (AHA, 2010) developed an aortic dissection risk score; however, it is retrospective, not validated, sensitivity 91% & specificity 40%.

    High-risk features of clinical exam

     

    History:

    • The “classic” chest/back/abdominal pain, sudden onset, severe and ripping or tearing with a wide mediastinum on CXR is not common ~ 2% of patients.
    • Syncope – up to 7%.
    • Perfusion deficit (CNS, myocardium, limb ischemia).
    • Some present with NO chest pain and only abdominal/back/lower leg pain!
    • Connective tissue disorder/Marfan’s syndrome.
    • Family history of aortic disease.
    • Aortic valve disease or aortic valve surgery.

     

    Physical:

    • Diastolic murmur of aortic regurgitation.
    • Pulse differential.
    • Systolic blood pressure differential (> 20mmHg) between arms.
    • Focal neurologic deficit (in conjunction with pain).
    • Hypotension/shock state.

     

    Chest x-ray:

    • Widened mediastinum (> 6cm upright PA film or > 8cm supine AP).
    • Up to 40-45% will be normal.

     

    Troponin:

    • Positive in 25%.

     

    ECG:

    • 1-2% may have ST elevation.

     

    D-dimer:

    • More studies required to validate use of D-dimer in AD.
    • ACEP 2014: DO NOT rely on D-dimer alone to exclude AD.

     

    Transthoracic Bedside Ultrasound

    • ACEP 2014: CV surgical consult or immediate transfer to higher level of care if US positive for dissection.

     

    CT Scan

    • Gold standard.
    • Aortic dissection may be missed if only ordering CT PE studies. If clinical suspicion, need to order Aortic Dissection specific CT protocol.
    • Triple rule out CT angiography (Ayaram et al. 2013): insufficient data to rule out AD.

    Which patients to transfer for CT (Ref: CMPA)

     

    Have you considered the diagnosis of aortic dissection in patients with:

    • Sudden onset of severe chest pain often with radiation, an intermittent course, and less frequently a pleuritic component.
    • Accompanying visceral manifestations (nausea, vomiting, pallor, and diaphoresis) normal or minimally abnormal ECG.
    • Normal or minimally abnormal ECG.

    Reliance only on classic features such as: ”tearing, BP/pulse discrepancies, new cardiac murmurs, and a widened mediastinum on CXR may be misleading.

    Management

    Quality Of Evidence?

    Justification

    • Transthoracic Ultrasound: ACEP level B.
    Moderate
    • AHA dissection score: Not a validated clinical decision score.
    Low
    • Treatment: No specific targets have shown reduction in mortality and morbidity.
    Low

    Related Information

    OTHER RELEVANT INFORMATION

    Reference List

    1. American College of Emergency Physicians Clinical Policies Subcommittee (Writing Committee) on Thoracic Aortic Dissection, Diercks DB, Promes SB, Schuur JD, Shah K, Valente JH, Cantrill SV. Clinical policy: critical issues in the evaluation and management of adult patients with suspected acute nontraumatic thoracic aortic dissection. Ann Emerg Med. 2015 Jan;65(1):32-42.e12. doi: 10.1016/j.annemergmed.2014.11.002.


    2. Nazerian P, Vanni S, Morello F, Castelli M, Ottaviani M, Casula C, Petrioli A, Bartolucci M, Grifoni S. Diagnostic performance of focused cardiac ultrasound performed by emergency physicians for the assessment of ascending aorta dilation and aneurysm. Acad Emerg Med. 2015 May;22(5):536-41. doi: 10.1111/acem.12650. Epub 2015 Apr 21.


    3. Asha SE, Miers JW. A Systematic Review and Meta-analysis of D-dimer as a Rule-out Test for Suspected Acute Aortic Dissection. Ann Emerg Med. 2015 Oct;66(4):368-78. doi: 10.1016/j.annemergmed.2015.02.013. Epub 2015 Mar 21.


    4. Konstantinides SV, Torbicki A, Agnelli G, Danchin N, Fitzmaurice D, Galiè N, Gibbs JS, Huisman MV, Humbert M, Kucher N, Lang I, Lankeit M, Lekakis J, Maack C, Mayer E, Meneveau N, Perrier A, Pruszczyk P, Rasmussen LH, Schindler TH, Svitil P, Vonk Noordegraaf A, Zamorano JL, Zompatori M; Task Force for the Diagnosis and Management of Acute Pulmonary Embolism of the European Society of Cardiology (ESC). 2014 ESC guidelines on the diagnosis and management of acute pulmonary embolism. Eur Heart J. 2014 Nov 14;35(43):3033-69, 3069a-3069k. doi: 10.1093/eurheartj/ehu283. Epub 2014 Aug 29.


    5. Ayaram D, Bellolio MF, Murad MH, Laack TA, Sadosty AT, Erwin PJ, Hollander JE, Montori VM, Stiell IG, Hess EP. Triple rule-outcomputed tomographic angiography for chest pain: a diagnostic systematic review and meta-analysis. Acad Emerg Med. 2013 Sep;20(9):861-71. doi: 10.1111/acem.12210.


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