Aortopathy

Introduction

  • Aortic aneurysm is pathologic dilation of part of the aorta
  • Management for aortic aneurysm centers around surveillance and managing cardiovascular risk factors
  • Aortic dissection is a life threatening disease that requires emergent surgery when involving the ascending aorta and generally medically managed otherwise

Aortic Aneurysm

Classifications

  • Aortic aneurysms are described in terms of location, size, morphology, and etiology
  •  True aneurysm (dilation of all walls):
    • Fusiform – uniform in shape and full circumference
    • Saccular – localized outpouching
  • Pseudoaneurysm (contained rupture)

Pathophysiology

  • Intima thickens in atherosclerosis and hypertension causes increases in wall stress
  • Degeneration of media and elastic components breakdown causing weakening of the aortic wall and dilation
  • Certain risk factors (below) predispose to weakening of aortic walls
Different types of aortic aneurysm

Risk Factors

  • HTN
  • Atherosclerosis
  • Family History
  • Aortitis
  • Smoking
  • Male
  • Connective tissue disease:
    • Marfans
    • Ehlers-Danlos
    • Loeys-Dietz
  • Bicuspid aortic valve

Presentation

  • Generally patients are asymptomatic and aneurysms picked up on screening or incidentally on other tests
  • Thoracic aortic aneurysms may present with chest or back pain.
    • If at the aortic root, may cause aortic regurgitation or coronary compression and ischemia
    • At the arch and descending aorta may cause dysphagia from esophageal compression or horners syndrome
    • Respiratory symptoms (wheeze, cough, dyspnea) also possible with tracheobronchial compression
  • Abdominal aortic aneurysms may present with abdominal, back, or flank pain (due to compression of other structures) or with symptoms of limb ischemia

Diagnosis

  • AAA
    • Abdominal ultrasound first line test given lack or radiation and availability
    • All men 65-80 should be screened once for AAA with an abdominal ultrasound
    • Can use CTA and MRA for further imaging
  • Thoracic aortic aneurysm
    • Generally picked up incidentally on chest x-ray, transthoracic echo or CT Thorax
    • CTA or MRA (recommended age < 50) of whole aorta recommended if concern thoracic aortic aneurysm

Management

  • AAA
    • Serial imaging every 6-12 months
    • Quitting smoking only therapy with proven benefit to reduce risk of rupture and exercise recommended (avoid heavy lifting
    • Risk factor modification (ASA and Statin)
    • Avoid fluoroquinolones
    • Repair (surgical vs endocascular) at 5.5cm or lower if high risk features
  • Thoracic aortic aneurysm
    • Serial imaging every 6-12 months
    •  Treat hypertension (target 140/90 or 130/80 if diabetes) and cardiac risk factors as per current guidelines (ASA and Statin if indicated)
      • beta blocker or ARB if Marfan’s
    • Repair (surgical vs endocascular) at 5.5cm or lower if high risk features (see table below for cutoffs)
. Recommended size thresholds for intervention for asymptomatic thoracic aortic aneurysms

Aortic Dissection

  • Tear in the aortic intima that results in blood entering the media layer of the aorta.
  • Variants include intramural hematoma, penetrating ulcer, traumatic/Iatrogenic.
  • Often classified by Stanford Classification:
    • Type A: This involves the ascending aorta and is a surgical emergency.
    • Type B: No involvement of ascending aorta and is usually treated medically.

Presentation

  • Acute onset, severe, tearing, chest pain.
  • Blood pressure differential between arms.
  • Chest pain with stroke symptoms -> Dissection until proven otherwise.
  • Can present as mimics: STEMI, valvular disease (AR), tamponade, syncope, stroke, renal failure, limb ischemia, spinal cord injury
BMJ 2011 Aortic Dissection

Diagnosis

JAMA

Focal neuro deficit (LR+ 6.6-33)
Pulse deficit/differential BP (LR+5.7)
Enlarged aorta or mediastinum on CXR (LR+ 2.0)

ECG

  • Usually will have non-specific ST or T wave changes.
  • May have ischemia type changes including ST elevation.
  • Patients can present as Inferior STEMI’s for two reasons. The first is a dissection is more likely to occur in the greater curvature and thus more likely to obstruct the RCA. Second Dissection into the left main is often fatal.

CXR

  •  May have findings such as a wide mediastinum.
  •  Trachea may be displaced because of the enlarging aorta.

CT (First Line)

  •  Widely available test than is usually first line in the assessment of aortic dissection.
  •  Allows assessment of other vascular beds involved in dissection and complications.

TTE

  • Not sensitive enough to rule out aortic dissection.
  • Hallmark of dissection is presence of a dissection flap this can sometimes be seen on TTE.
  • May also see an enlarge aorta.
  • Aortic regurgitation frequently accompanies a dissection.
  • Pericardial effusion in particular bloody effusion may be suggestive that the dissection has migrated into the pericardium.

TEE

  •  Sensitive test to rule out aortic dissection 95-100%.
  •  Artifacts may mimic dissection flaps.
  •  There is a “blind spot” on TEE between the interposition of the trachea and ascending aorta.

Management

  •  Treat pain aggressively with narcotics.
  •  Anti-Impulse therapy: Use IV beta-blockers or calcium channel blocker. These medications reduce blood pressure and left ventricular contraction = less shear wall stress of aorta and reduces dissection propagation.Target a heart rate of < 60 and a systolic blood pressure between 100-120 mmHg. IV Esmolol or Labetalol is a good option as short half life in case hemodynamics change.
  •  Afterload reduction (If still Hypertensive): Nitroprusside a good option is patient still hypertensive. Do NOT use afterload reduction agents without a beta-blockers or calcium channel blockers on board as vasodilation will lead to reflex tachycardia which may increase left ventricular contraction and worsen dissection.
  • Surgical consultation.
    • Type A dissection is a surgical emergency need immediate OR. Untreated type A dissection have a 50% mortality!
    • Type B dissection can be managed medically especially if no other end-organ damage.

Further Reading

  • 2014 CCS: Management of Thoracic Aortic Disease (html) (pdf)

Authors

  • Authors: Atul Jaidka (MD, FRCPC, Cardiology Resident), Daniel Durocher(MD, FRCPC, Cardiologist, ICU Fellow)
  • Staff Reviewer: pending (MD, FRCPC[Cardiology])
  • Last Updated: June 9, 2021
  • Comments or questions please email feedback@cardioguide.ca
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