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Paucis Verbis: International Registry on Aortic Dissection (IRAD)


What do these three people have in common? 

  • Lucille Ball (comedienne)
  • Jonathan Larson (wrote the musical “Rent”)
  • John Ritter (comedian)

They all died from an aortic dissection. We commonly consider this diagnosis for Emergency Department patients presenting with severe chest pain. There is an International Registry on Aortic Dissection which published a retrospective, descriptive study of 464 patients with aortic dissections.

I find this list helpful, because it illustrates the fact that the classic signs and symptoms aren’t actually very common. Here are some scary examples:

  • A pulse deficit in the carotid, brachial, and femoral arteries is only present 15% of the time.
  • A tearing or ripping quality of pain is present in only 50% of patients.
  • Not all patients have a widened mediastinum or abnormal aortic contour (only 78.7%).

PV Card: Aortic Dissection

Adapted from 1
Go to the ALiEM Cards site for more resources.

Hagan PG, Nienaber CA, Isselbacher EM, et al. The International Registry of Acute Aortic Dissection (IRAD). JAMA. 2000;283(7):897. doi: 10.1001/jama.283.7.897
Michelle Lin, MD
ALiEM Editor-in-Chief
Academy Endowed Chair of EM Education
Professor of Clinical Emergency Medicine
University of California, San Francisco
Michelle Lin, MD
Michelle Lin, MD

Latest posts by Michelle Lin, MD (see all)

  • Michelle:

    Some of the figures in the chart may be a little misleading because of spectrum bias — they apply to cases of aortic dissection that have already been diagnosed. The actual statistics can be quite different when a patient presents early with mild and/or nonspecific symptoms.

    For example, it may be true that 79% of patients with dissection when they are diagnosed have abnormal CXR findings — that may be one of the reasons the diagnosis was made. This is often a point put forward by plaintiff’s attorneys in medical-legal cases: “If only the doctor had ordered a simple chest x-ray when the patient presented with mild epigastric/chest pain!” However, there is good evidence that on initial presentation well under half the CXRs will be abnormal.

    Two important quotations:

    1) “In fact, difficulty in diagnosis, delayed diagnosis or failure to diagnose [aortic dissection] are so common as to approach the norm for this disease, even in the best hands, rather than the exception.” (Elefteriades et al. Litigation in Nontraumatic Aortic Diseases — A Tempest in the Malpractice Maelstrom. Cardiology 2008;109:263-272.

    2) “There is no disease more conducive to clinical humility than aneurysm of the aorta.” Sir William Osler

  • Hi Leon:
    Thanks for eloquently describing the pitfalls in risk-stratifying for diseases using retrospective data. I don’t think there will ever be a prospective study though on dissection where every chest/back pain patient receives a CT angiogram of the chest, especially in the setting of CT irradiation risks. We can only do our best and have a low-threshold to obtain a D-Dimer (which has ok sensitivity for aortic dissection) and Chest CT angio. Experience has taught me to definitely be humble with aortic diseases. Thanks for commenting!

  • Whenever I read IRAD, I realize the limitations that we ED docs have when diagnosing AD. Some patients can present with “absoulutely no pain at all.”

    Thanks for another PV.

  • I know what you mean, JD. I sometimes wish I read IRAD more and other times I wish I never read it at all. Scary data.

  • Wow I don’t think I would think of aortic dissection if they came in with NO pain. Last dissection I diagnosed in the ED had severe excruciating pain unrelieved after multiple doses of dilaudid. He did have pain down into his thighs too. That is scary.

    • I know, scary right? I wonder if the major of these pain-less presentations are those who are either obtunded, intubated, or present with syncope and are still altered.

  • EmDick

    I tried getting some irad data to answer a question but had great difficulty, seems like a difficult exclusive club in this modern age of information sharing for the good of our patients… Any ideas how to look at this raw data?

    • Michelle Lin

      Hmm no backdoor entries that I know of. Only can see what’s available on this JAMA 2000 paper. Perhaps contact one of the authors? Good luck.