Aortic Dissection

/ Maninder Singh, M.D.

Follow-up Rounds
1/22/2016
Article inspired by: Dr. Joshua Schwarzbaum, PGY-3

THE CASE

60 y/o F PMHx HTN BIBEMS after bystanders called for erratic behavior. As per triage nurse, patient is rambling while speaking and diaphoretic but with no visible injuries. Patient reports he cannot breathe and that he was told he passed out while walking his dog. He reports he feels cold and sweaty. Denies fevers, chills, nausea, vomiting, chest pain, abdominal pain, or recent travel.

EKG- sinus tachycardia

Physical Exam:
Vitals: BP- 106/74, HR-107, RR-20, Temp-96F, SpO2- 94%, FS- 125
General: Mild distress, lying in bed
Chest: CTA b/l
Cardiovascular- S1/S2, Tachycardic
Abdomen- Soft, NT/ND
Extremities- Warm, No peripheral edema
Neurological- Waxing/waning mental status, PERRL, Moving all extremities, Will not comply with exam

Labs:
138/hemolyzed/108/17.4/14/1.5<265
15.2>15.4/46.3<184
Trop: 0.22, CK: 235

CXR: No acute cardiopulmonary process

CT Head: No acute intracranial pathology

CT Chest: Findings are consistent with bibasilar pulmonary emboli, extremely slow flow through the heart and evidence of heart failure with smooth thickening of the interstitium and geometric polygons formation. Bibasilar atelectasis/infiltrate. Moderate pericardial effusion which is hemorrhagic in nature and with a history of hypertension, rule out dissection of the aorta which is not opacified due to extremely slow flow.

Echocardiogram:

TTE
TEE

THE TALK

Is there a way to classify aortic dissections?

  • Arbitrary way: Acute (<2 weeks of symptoms) vs Chronic
    • Life threatening complications 2/2 branch involvement or aortic rupture more common in acute
  • Stanford Classification
    • Type A
      • Involving ascending aorta, regardless of site of primary intimal tear
    • Type B
      • Everything else
  • Debakey Classification
    • Type 1
      • Originating in ascending aorta and propagating to at least aortic arch
    • Type 2
      • Originating in and confined to ascending aorta
    • Type 3
      • Originating in the descending aorta and extending distally or proximally

What type of dissection is more common?

  • Ascending aortic dissection ~2x more common than descending aortic dissection
    • Right lateral wall of ascending aorta = most common site
    • Aortic arch involvement occurs in ~30%

How does an aortic dissection happen?

  • Primary event = tear in aortic intima
  • Blood passes into aortic media through tear, creating false lumen
  • Related to shear forces

How can people die from aortic dissection?

  • Rupture of dissection into pericardium leading to cardiac tamponade
  • Acute dissection of aortic valvular annulus leading to severe aortic regurgitation
  • Obstruction of coronary artery ostia leading to MI
  • Abdominal aortic branch vessel obstruction leading to end organ failure

What are some risk factors for aortic dissection?

  • HTN (abrupt, transient, severe increase in BP, ex: crack cocaine or high intensity weight lifting)
  • Collagen disorders (ex: Marfan, Ehler-Danlos, annuloaortic ectasia)
  • Preexisting aortic aneurysm
  • Bicuspid aortic valve (always involves ascending aorta)
  • Aortic instrumentation/cardiac surgery
  • Aortic coarctation
  • Turner syndrome
  • Vasculitis (ex: Giant cell arteritis, Takayasu arteritis, RA, Syphilitic aortitis)
  • Trauma (but usually causes aortic rupture or transection)
  • Pregnancy/Delivery

What are some things I should elicit on my H&P?

  • Acute pain (typically severe, sharp/knife-like)
    • Abdominal pain/Mesenteric ischemia (think celiac or mesenteric arteries involvement)
    • Back or flank pain/Renal failure (think renal artery involvement)
  • Pulse deficit (a weak or absent carotid, brachial, or femoral pulse resulting from the intimal flap or compression by hematoma)
    • Upper extremity pulselessness/Hypotension (think subclavian artery involvement)
    • Lower extremity pain/pulselessness/weakness (think common iliac artery involvement)
  • Heart murmur (new diastolic decrescendo murmur)
    • Aortic insufficiency/Heart failure (think aortic valve involvement)
  • Focal neurologic deficit
    • Stroke/Syncope (think brachiocephalic, common carotid or left subclavian artery involvement)
    • Paraplegia (think intercostal artery involvement as they give off spinal/vertebral artery)
    • Horner syndrome (ptsosis/miosis/anhidrosis) (think superior cervical sympathetic ganglion involvement)
  • Hypotension
    • Cardiac tamponade (think pericardium involvement)
    • MI (think right coronary artery involvement)
    • Hemothorax/Hemoperitoneum (think thoracic or abdominal aorta involvement)

How do I manage someone with aortic dissection?

  • Pain control with narcotics (morphine)
  • If hemodynamically unstable/airway compromise, intubate
  • Heart rate control to <60bpm (IV beta blocker ex: propranolol or labetalol)
    • Labetalol is an alpha- and beta-receptor antagonist (may be more effective in controlling both heart rate and blood pressure as a single agent)
    • Esmolol has short half-life and can be titrated to effect
    • Esmolol also beneficial in asthma or heart failure (pts who are intolerant to BB)
    • Other options if cannot use BB: Verapamil or Diltiazem
  • Reduction of systolic blood pressure of 100-120mmHg
    • If after BB, still elevated- can use Nitroprusside (but only after BB because vasodilation alone induces reflex activation of sympathetic nervous system -> enhanced ventricular contraction -> increased aortic wall shear stress)
    • Can use ACE-inhibitors
    • AVOID HYDRALAZINE (increases aortic wall shear stress)

What if my patient is hypotense?

  • Prior to giving volume, determine cause:
    • Blood loss
    • Hemopericardium with tamponade
    • Valvular dysfunction
    • Left ventricular systolic dysfunction
  • AVOID inotropic agents (increase aortic wall shear stress)

REFERENCES

Schwarzbaum J. “Follow up Rounds: Aortic Dissection” Jacobi Medical Center. Jacobi/Montefiore Emergency Medicine Conference. Bronx. Jan 2016. Case Presentation

Manning, Warren J., and James H. Black. “Clinical Features and Diagnosis of Acute AorticDissection.” Clinical Features and Diagnosis of Acute Aortic Dissection. UpToDate, 19 Feb. 2016. Web.

Manning, Warren J. “Management of Aortic Dissection.” Management of Aortic Dissection. UpToDate, 20 Nov. 2013. Web.

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