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Aortic Dissection: A Case Series - Part 1

Mizuho Spangler, DO and Sam Ashoo, MD
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Aortic dissection is a time sensitive life threatening diagnosis that we simply cannot miss. Patients who present to the outpatient setting need to be quickly identified for expeditious transfer for further workup and treatment. Miz and Sam Ashoo discuss both typical and atypical presentations for aortic dissection.

 

Pearls:

  • Listen to your 6th sense.  Have a heightened level of suspicion for patients who present with chest pain and hypertension or chest pain and drug use or chest pain that is tearing and radiating to the back or a pulse deficit between arms.

  • The minute you have a neurologic complaint that accompanies chest pain, Aortic Dissection must move to the top of your differential.

  • EKGs, CXRs, d-dimers are all incredibly insensitive for aortic dissections and should not be relied upon for ruling in or out dissection.

 

  • Aortic dissection is a very scary diagnosis to make, particularly in the Urgent Care or other outpatient setting where we do not have immediate access to cardiothoracic surgery

  • The diagnosis is time sensitive and very anxiety provoking because these patients can die very quickly.

  • Sam describes 3 cases he has seen in the past year.  Each one presented somewhat atypically and could have easily walked into any Urgent Care.

    • CASE #1: A 50yo woman with no past medical history is eating at a Mexican restaurant and developed abdominal pain.  She reports that the pain started suddenly and traveled up into her chest.  She briefly lost vision in her right eye.  The pain traveled back down into her stomach and then resolved.  Her vision came back as well.  The whole episode lasted less than 15 minutes and by the time she arrives at the free-standing ED, she is completely symptom-free.

      • Blood pressure on arrival is 88 systolic.  This is her only remarkable physical exam finding.

      • Repeat blood pressure her other (right) arm is 120 systolic

    • CASE #2: A 45yo woman with PMH of migraine headaches presents with sudden onset of chest pain that radiates “to the back of my throat” and her vision “seems brighter in my right eye”.

      • SBP 91 mmHg

      • Heart murmur on exam that was unknown to the patient

    • CASE #3: A 65yo woman who is a former ballet dancer and runs on the treadmill daily presents after syncope during her run.  On arrival, her blood pressure is normal and she reports some chest pain prior to passing out.  Now she reports lower back pain and right leg weakness and tingling.  Repeat BP shows a systolic BP 88mmHg.

      • CT shows dissection along the entire course of the aorta down into her right iliac.

  • Sam describes that he made the diagnosis in the first case simply by thinking about her complaints in the context of anatomy.  What could possibly tie the abdominal pain, chest pain and vision loss together?

  • Remember: the minute you have a neurologic complaint that accompanies chest pain, aortic dissection must move to the top of your differential.

 

AORTIC DISSECTION

  • A tear in one or more of the 3 layers of the vessel:

    • Intima - where the tear starts

    • Media

    • Adventitia

  • Classified into 2 types:

    • Type A dissection - involves the ascending portion of the aorta (regardless of how far it travels down the descending aorta).

    • Type B dissection - only involves the descending aorta

  • Aortic dissections carry a really high mortality

    • Dissections are 2-3 times more common than an abdominal aortic aneurism.

    • Mortality

      • 33% mortality in the first 24 hours if it is left untreated

      • 50% mortality at 48 hours

      • 75% mortality at 2 weeks

  • Risk factors:

    • Older patients with stiff blood vessels from a long history of hypertension.

    • Drug users, particularly cocaine users who are exposed to huge sympathetic surges in blood pressure.

    • People with connective tissue disorders (Marfan, Ehlers Danlos, etc.) have weakened blood vessel walls.

      • One problem with connective tissue disorders is that many people do not know they have one.

    • Previous heart surgery

    • Tertiary syphilis

    • Inflammatory vasculitis

    • Pregnancy - particularly in the 3rd trimester (hormones + hyperdynamic state expose patients to dissections).

  • TYPICAL PRESENTATION

    • PAIN

      • Abrupt onset of abdominal or chest pain with sharp, tearing or ripping character

      • Radiation toward the upper or lower back

    • BLOOD PRESSURE

      • A variation in the pulse: absence of a proximal extremity or carotid pulse or BP differential of > 20mmHg between the upper extremities.

        • Should not be used to screen for dissections.  However, if a pulse deficit or SBP discrepancy of about 20mmHg is present in someone who is symptomatic, dissection is more likely.

      • Blood pressure abnormalities

        • Type B dissections most commonly (70%) present with hypertension

        • Type A dissections can present either way:

          • 25-30% present with hypertension

          • 25% presenting with hypotension

          • The rest present with normal BP

    • HEART MURMUR

      • A new, or presumed-new diastolic murmur is indicative of aortic regurgitation.

      • Heard high on the right sternal border

    • NEURO FINDING - Deficits can be variable

      • Stroke - as the dissection progresses up and into the carotids.

      • Horner’s syndrome - if the dissection compresses the superior cervical sympathetic ganglion.

      • Hoarseness or voice changes - from vocal cord paralysis or compression of the laryngeal nerve

      • Paraplegia - from spinal cord infarction

      • Syncope - the presenting complaint in 5-10% of dissections and is more common in Type A dissections.

  • ATYPICAL PRESENTATION

    • Pain-free: patients may tell you then have no pain, but it is important to ask specifically if they had pain previously (i.e. before they syncopized or developed leg weakness).

    • Women are more likely to present atypically.

 

  • What do we do in the Urgent Care?

    • The definitive diagnosis or exclusion of aortic dissection relies on contrast CT, and most of us in the UC do not have access to this type of study.

    • What work up should we do?

      • EKG - not sensitive

        • Will only see changes if the dissection involves the coronary ostia

        • Hagan PG, et al. The International Registry of Acute Aortic Dissection (IRAD): new insights into an old disease. JAMA. 2000 Feb
          16;283(7):897-903 [Free open access link]

          • Suggests that involvement of the coronary artery in an aortic dissection may not even manifest changes on EKG

          • Looked at 464 patients with aortic dissections

            • Normal EKG - 31%

            • Non-specific ST and T wave changes - 42%

            • Ischemic changes - 15%

        • While EKGs should be obtained in chest pain patients to evaluate for other life threatening causes of chest pain like STEMIs and arrhythmias, it cannot be relied upon exclusively for ruling out or in aortic dissection.

      • CXR -

        • A widened mediastinum helps increase suspicion for aortic dissection (will see a widened mediastinum in 60-90% of cases)

        • IRAD study (Hagan, referenced above) also found

          • 63% of patients with a Type A dissection had widened mediastinum, but 11% had no CXR abnormalities at all

          • 56% of patients with Type B dissections had a widened mediastinum and 16% had no abnormality on CXR

        • Classic findings in addition to widened mediastinum:

          • Pleural effusions

          • Widening of the aortic contour

          • Displaced calcification

          • Aortic kinking

          • Hemothorax

        • CXR alone has very low sensitivity for ruling out dissection.  As with EKGs,  a CXR can increase your suspicion if it has certain findings, but if it is normal is not helpful at all.

      • D-dimer -

        • Can be elevated in dissection due to the aortic intimal tearing

        • Multiple laboratory studies have been looked at, but none have proven sensitive or specific enough to be useful.

      • US -

        • Can be useful in the hands of trained individuals, but is not standard of care for making or excluding the diagnosis.

    • In the UC setting, if our suspicion is high, we should not waste time on any of these studies.  We should be stabilizing the patient and transferring them out via 911.

      • Type A dissections are treated surgically.

      • Type B dissections are treated primarily medically, but patients may be candidates for endograph stenting.

      • It is very important that you speak to a doctor in the ED  to which the patient is heading so they know the patient is coming and what you are worried about to prevent the situation that a patient is mistriaged and sits in the waiting room for hours.

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Dissecting Into The Heart Of The Matter Full episode audio for MD edition 191:45 min - 90 MB - M4AHippo Urgent Care RAP - September 2017 Written Summary 293 KB - PDF

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