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
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)
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
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
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