- 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
- Type A: Involves ascending aorta +/- descending aorta (60% of dissections).
- Type B: Involves only the descending aorta.
- I – Ascending aorta which extends to at least the aortic arch +/- descending aorta.
- II – Only the ascending aorta.
- III – Only the descending aorta.
- 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
- 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.
- Diastolic murmur of aortic regurgitation.
- Pulse differential.
- Systolic blood pressure differential (> 20mmHg) between arms.
- Focal neurologic deficit (in conjunction with pain).
- Hypotension/shock state.
- Widened mediastinum (> 6cm upright PA film or > 8cm supine AP).
- Up to 40-45% will be normal.
- Positive in 25%.
- 1-2% may have ST elevation.
- 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.
- 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.
- Decrease the BP and pulse if they are elevated.
- European guidelines recommend SBP 100-120mmHg.
- Use labetolol 20mg IV, onset is within 5-10 minutes, q10 min to max of 300mg.
- May use a labetolol infusion at 2mg/min.
- Insert an arterial line if possible.
- For transport considerations, see: Interfacility transport of acute & critically ill patients in British Columbia
Quality Of Evidence?
We are highly confident that the true effect lies close to that of the estimate of the effect. There is a wide range of studies included in the analyses with no major limitations, there is little variation between studies, and the summary estimate has a narrow confidence interval.
We consider that the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. There are only a few studies and some have limitations but not major flaws, there are some variations between studies, or the confidence interval of the summary estimate is wide.
When the true effect may be substantially different from the estimate of the effect. The studies have major flaws, there is important variations between studies, of the confidence interval of the summary estimate is very wide.
- Transthoracic Ultrasound: ACEP level B.
- AHA dissection score: Not a validated clinical decision score.
- Treatment: No specific targets have shown reduction in mortality and morbidity.
OTHER RELEVANT INFORMATION
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.
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.
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.
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.
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.
The purpose of this document is to provide health care professionals with key facts and recommendations for the diagnosis and treatment of patients in the emergency department. This summary was produced by the BC Emergency Medicine Network and uses the best available knowledge at the time of publication. However, healthcare professionals should continue to use their own judgment and take into consideration context, resources and other relevant factors. The BC Emergency Medicine Network is not liable for any damages, claims, liabilities, costs or obligations arising from the use of this document including loss or damages arising from any claims made by a third party. The BC Emergency Medicine Network also assumes no responsibility or liability for changes made to this document without its consent.
Last Updated Sep 15, 2018
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