Nontraumatic thoracic aortic dissection

(Redirected from Thoracic Aortic Aneurysm)

Not to be confused with traumatic aortic transection

Background

Aortic segments
Branches of the aorta
Aortic anatomy. The aorta is divided into 5 anatomical segments– aortic root, ascending aorta, aortic arch, descending thoracic aorta, and abdominal aorta. Its wall is composed of three layers – intima, media, and adventitia.
  • Most commonly seen in men 60-80 yrs old
  • Intimal tear with blood leaking into media
  • Mortality in first 48 hours of acute presentation is high
    • Commonly quoted as 1-2% per hour, but this is based on a series from the 1950s[1]
    • More recent data suggests mortality for type A dissection is 0.5% per hour when treated medically, and 0.1% per hour when managed surgically[2]
  • Diagnosis delayed > 24hr in 50% of cases
  • Bimodal age distribution

Clinical Features

General

  • Symptoms
    • Tearing/ripping pain (10.8x increased disease probability)
      • 64% described the pain as sharp vs 50.6% who described it as tearing or ripping[3]
    • Migrating pain (7.6x)
    • Sudden chest pain (2.6x)
    • History of hypertension (1.5x)
  • Signs

Specific

Differential Diagnosis

Chest pain

Critical

Emergent

Nonemergent

Hypertension

Evaluation

Dissection of the aortic arch: initial CXR normal visualization of the calcification shadow in the aortic arch (left); CXR 4 months later with calcification shifted centrally into the shadow of the aortic arch with a blurred external border (middle); CT scan coronal (top right) and axial (lower right).
CXR showing widened mediastinum and porminent aortic knob
Type A dissection with pericardial effusion as a result. Red arrows showing ascending and descending thoracic aorta. The blue arrows pericardial effusion.
CT chest with contrast of thoracic aortic dissection.

Aortic Dissection Detection Risk Score (ADD-RS)

A score 1 should be awarded for each of the 3 categories that contain at least one of the listed features

Predisposing conditions Pain features Physical findings

Chest, back, or abdominal pain described as:

  • Abrupt in onset/severe in intensity

AND

  • Ripping/tearing/sharp or stabbing quality
  • Evidence of perfusion deficit
    • Pulse deficit
    • Systolic BP differential
    • Focal neurological deficit (in conjunction with pain)
  • Murmur of aortic insufficiency (new or not known to be old and in conjunction with pain)
  • Hypotension of shock state
Score Category Prevalence
0 Low 6%
1 Intermediate 27%
>1 High 39%

No Risk Factor Screening

  • CXR
    • Abnormal in 90% (3.4x)
    • Mediastinal widening (seen in 56-63%)
    • Left sided pleural effusion (seen in 19%)
    • Widening of aortic contour (seen in 48%), displaced calcification (6mm), Calcium sign (look for white line of calcium within aortic knob and measure to outer edge of the aortic knob - distance greater than 0.5 cm is positive and > 1 cm is highly suspicious for dissection), aortic kinking, double density sign


Low-Intermediate

(Based on ADD-RS)[6][7][8]

  • D-dimer for ADD-RS ≤ 1 (low or intermediate risk)

High Risk/Definitive

  • CT aortogram chest
    • Study of choice
    • Similar sensitivity/specificity to TEE and MRA
  • TEE
    • If CT delayed due to contrast allergy or availability, or patient instability.
    • TEE has a sensitivity of 98% and 95% specific[9]

Other Findings

Type A Aortic Dissection[10]
Abdominal Aortic Dissection on Ultrasound
  • ECG
    • LVH on admission ECG (3.2x)
    • Ischemia (esp inferior) - 15%
    • Nonspec ST-T changes - 40%
  • Bedside US
    • Can help in ruling in patients when AOFT is >4cm
    • Rule out pericardial effusion and tamponade, especially in hypotension, syncope, dyspnea

Aortic Dissection Classification

  • Stanford
    • Type A: Involves any portion of ascending aorta
    • Type B: Isolated to descending aorta
  • De Bakey
    • Type I: Involves the ascending and descending aorta
    • Type II: Involves only the ascending aorta
    • Type III: Involves only the descending aorta
Classification of aortic dissection
Image AoDissect DeBakey1.png AoDissect DeBakey2.png AoDissect DeBakey3.png
Percentage 60% 10–15% 25–30%
Type DeBakey I DeBakey II DeBakey III
Classification Stanford A (Proximal) Stanford B (Distal)

Management

General Principles

  • Control pain to reduce sympathetic stimulation.
    • Fentanyl is easily titratable with minimal cardiovascular effects
  • Right radial arterial line or right arm blood pressure will generally be the most accurate
  • Reducing heart rate while maintaining low-normal blood pressure reduces aortic flow acceleration, thereby reducing shear force on the intimal wall
    • Goal: HR < 60 bpm, SBP 100-120 mmHg
    • Control heart rate before blood pressure[11]
    • Beta blockers are good first-line option, since they reduce heart rate and aortic wall tension
      • Use β-blockers with caution in severe, acute aortic regurgitation - may worsen shock if dependent on compensatory tachycardia

Heart Rate control

  1. Esmolol
    • Advantage of short half life, easily titratable
    • Bolus 0.5mg/kg over 1min; infuse 0.05mg/kg/min (titrate upward in 0.05mg/kg/min increments to a maximum of 0.3 mg/kg/min)
    • Esmolol Drip Sheet
  2. Labetalol - has both α and beta effects
    • Push dose - 10-20mg with repeat doses of 20-40mg q10min up to 300mg
    • Drip - Load 15-20mg IV, followed by 5mg/hr
  3. Metoprolol
    • 5mg IV x 3; infuse at 2-5mg/hr
  4. Diltiazem - Use if contraindications to beta-blockers
    • Loading 0.25mg/kg over 2–5 min, followed by a drip of 5mg/h

Blood pressure control (vasodilators)

Use if needed after beta-blockade.

  1. Nicardipine:
    • 5mg/hr start, then titrate up by 2.5mg/hr every 10 min until goal
    • Once at goal, drop to 3mg/hr and re-titrate from there
    • May initially bolus 2mg IV[12]
  2. Clevidipine
    • 1-2 mg/hr
    • Double dose every 90 seconds until approaching goal BP, then increase in smaller amounts every 5-10 minutes until goal achieved.[13]
  3. Nitroprusside 0.3-0.5mcg/kg/min - Risk of cerebral blood vessel vasodilation and CN/Thiocynate toxicity
  4. Fenoldopam
  5. Enalapril

Surgery

  • Type A (any portion of ascending aorta)
    • Requires surgery
  • Type B (isolated to descending aorta)
    • Primarily medical management with surgery consultation

Disposition

  • Admission to OR or ICU

Complications

  • AV Regurgitation/Insufficiency
    • CHF with diastolic murmur
  • Rupture
  • Vascular obstruction
    • Coronary: ACS
    • Carotid: CVA
    • Lumbar: Paraplegia

See Also

External Links

References

  1. ↑ Hirst AE Jr, et al. Dissecting aneurysm of the aorta: a review of 505 cases. Medicine (Baltimore). 1958;37(3):217-279.
  2. ↑ Harris, KM. et al. Early mortality in type A acute aortic dissection: Insights from the International Registry of Acute Aortic Dissection. JAMA Cardiol. 2022;7(10):1009-1015.
  3. ↑ Hagan PG, Nienaber CA, Isselbacher EM, et al. The International Registry of Acute Aortic Dissection (IRAD): new insights into an old disease. JAMA. 2000;283(7):897–903.
  4. ↑ 4.0 4.1 4.2 Hagan PG, Nienaber CA, Isselbacher EM, et al. The International Registry of Acute Aortic Dissection (IRAD): new insights into an old disease. JAMA. 2000; 283(7):897-903.
  5. ↑ Spittell PC, S et al. Clinical features and differential diagnosis of aortic dissection: experience with 236 cases (1980 through 1990) Mayo Clin Proc. 1993;68:642–51.
  6. ↑ Circulation. 2018 Jan 16;137(3):250-258. doi: 10.1161/CIRCULATIONAHA.117.029457. Epub 2017 Oct 13. Nazerian, et al. Diagnostic Accuracy of the Aortic Dissection Detection Risk Score Plus D-Dimer for Acute Aortic Syndromes: The ADvISED Prospective Multicenter Study.
  7. ↑ Asha SE et al. "A systematic review and meta-analysis of D-dimer as a rule out test for suspected acute aortic dissection." Annals of EM. 66;4;368-377Ocotber 2015.
  8. ↑ Shimony A, et al. Meta-analysis of usefulness of d-dimer to diagnose acute aortic dissection. Am J Cardiol. 2011; 107(8):1227-1234.
  9. ↑ Shiga T, Wajima Z, Apfel CC, Inoue T, Ohe Y. Diagnostic accuracy of transesophageal echocardiography, helical computed tomography, and magnetic resonance imaging for suspected thoracic aortic dissection: systematic review and meta-analysis. Arch Intern Med. 2006 Jul 10;166(13):1350-6.
  10. ↑ http://www.thepocusatlas.com/echocardiography-1
  11. ↑ Tsai TT, Nienaber CA, and Eagle KA. Acute Aortic Syndromes. Circulation. 2005;112:3802–3813
  12. ↑ Curran MP et al. Intravenous Nicardipine. Drugs 2006; 66(13): 1755-1782. http://emcrit.org/wp-content/uploads/2014/07/bolus-dose-nicardipine.pdf
  13. ↑ UpToDate Inc. Clevidipine [Drug information]. In:UpToDate Lexidrug. Wolters Kluwer; 2025. Accessed August 1, 2025.
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