64-Year-Old Male Under Surveillance for Aortic Pathology, Anomalous Aortic Origin of the Left Coronary Artery with an Interarterial Course

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 AAOLCA: Anomalous aortic origin of the left coronary artery with an interarterial course

Anomalous aortic origin of the left coronary artery with an interarterial course (AAOLCA) is a rare congenital coronary artery anomaly that carries potential clinical significance due to its association with sudden cardiac death, particularly in young individuals.

 

1. Cause and Etiology

AAOLCA is a congenital anomaly, meaning it is present at birth and results from abnormal embryological development of the coronary arteries. During normal development, the coronary arteries form from vascular endothelial buds that penetrate the aortic sinuses. Malrotation, displacement, or misconnection during this process can lead to an anomalous origin.

In AAOLCA, the left coronary artery (LCA) arises abnormally from the right coronary sinus (RCS) or adjacent aortic wall instead of the left coronary sinus (LCS), and takes an interarterial course between the aorta and the pulmonary artery, which can be hemodynamically significant.

2. Pathophysiology

The interarterial course of the anomalous LCA is of particular concern due to several pathophysiological mechanisms:

  • Compression during exercise or exertion: During physical activity, both the aorta and pulmonary artery dilate, which can compress the anomalous LCA sandwiched between them, leading to myocardial ischemia.
  • Slit-like ostium and acute take-off angle: The LCA may have a narrow, slit-like origin and arise at an acute angle, limiting blood flow, especially under high cardiac demand.
  • Intramural segment: The initial part of the LCA may course within the wall of the aorta (intramural), which may collapse during systole, exacerbating ischemia.
  • Endothelial dysfunction or chronic hypoperfusion: These may develop over time in response to chronic intermittent ischemia.

These features increase the risk of myocardial ischemia, arrhythmia, syncope, and sudden cardiac death (SCD), especially in young athletes.

3. Epidemiology

  • Prevalence: Coronary artery anomalies are seen in approximately 1% of the general population, with AAOLCA being rarer than anomalous right coronary origin.
  • Sudden cardiac death: AAOLCA is one of the leading causes of sudden cardiac death in young athletes, especially during or after strenuous physical activity.
  • Age group: Most cases are asymptomatic during infancy and childhood, with clinical manifestations often appearing during adolescence or young adulthood.

4. Clinical Presentation

The clinical spectrum ranges from asymptomatic to fatal. Symptoms are often exertional and include:

  • Chest pain (angina-like, especially with exertion)
  • Syncope or presyncope
  • Palpitations
  • Exertional dyspnea
  • Sudden cardiac death (particularly during or immediately after exercise)

In many cases, AAOLCA is incidentally discovered during imaging for unrelated reasons or after a cardiac event.

5. Imaging Features

Imaging plays a central role in diagnosis. Key modalities and findings include:

a.       Echocardiography


  • Limited in sensitivity but may suggest abnormal coronary origin in children.
  • Transesophageal echocardiography (TEE) improves visualization in older patients.

b.       Coronary Computed Tomography Angiography (CCTA)

  • Modality of choice
  • Clearly delineates:
    • Origin of LCA from the right coronary sinus
    • Interarterial course between the aorta and the pulmonary artery
    • Intramural segment if present
  • Offers 3D visualization for surgical planning.

c.       Cardiac Magnetic Resonance Imaging (CMR)

  • Provides similar anatomic detail to CT
  • Adds functional data (e.g., perfusion, myocardial viability)

d. Invasive Coronary Angiography

  • May be used, but has limitations in defining the 3D course
  • Can evaluate dynamic compression using intravascular ultrasound (IVUS) or fractional flow reserve (FFR)

6. Treatment

Management depends on symptoms, anatomy, and risk profile.

a. Surgical Repair (definitive)

  • Indications:
    • Symptomatic patients (e.g., exertional angina, syncope)
    • High-risk anatomy (e.g., intramural course, slit-like ostium)
    • Patients with documented ischemia
  • Procedures:
    • Unroofing of the intramural segment
    • Ostial relocation or reimplantation
    • Coronary artery bypass grafting (CABG) (less favored in younger patients)

b. Medical Management

  • Beta-blockers to reduce myocardial oxygen demand and prevent arrhythmias
  • Activity restriction, especially competitive sports

c. Observation

  • In select asymptomatic cases with low-risk anatomy, especially in older adults

7. Prognosis

  • With early diagnosis and surgical correction, the prognosis is excellent.
  • Uncorrected high-risk cases (especially with interarterial/intramural course) carry a significant risk of SCD, particularly during exertion.
  • Post-operative outcomes are generally good, with return to normal activities in many cases after full recovery and risk assessment.

Summary Table

Aspect

Description

Cause

Congenital defect in coronary artery embryogenesis

Pathophysiology

Ischemia due to compression, slit-like ostium, acute take-off, intramural course

Epidemiology

Rare; <1% of population; leading cause of SCD in young athletes

Symptoms

Exertional chest pain, syncope, SCD

Imaging

CCTA and CMR are gold standards for anatomical definition

Treatment

Surgery (unroofing, reimplantation); beta-blockers; avoid exertion

Prognosis

Excellent with timely surgery; poor if undiagnosed or untreated in high-risk cases

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Case Study: 64-Year-Old Male Under Surveillance for Aortic Pathology 

Anomalous Aortic Origin of the Left Coronary Artery with an Interarterial Course

History and Imaging Findings

  1. A 64-year-old male presented for follow-up evaluation of known aortic pathology.

  2. He reported no chest pain or dyspnea.

  3. Chest CT angiography revealed the following findings:

Quiz:

  1. What is the primary finding in the thoracic aorta?
    (1) Stanford type A aortic dissection
    (2) Stanford type B aortic dissection 
    (3) Penetrating atherosclerotic ulcer
    (4) Intramural hematoma
    Explanation: CT angiography reveals a dissection that originates distal to the left subclavian artery, consistent with Stanford type B.

  2. What is the key finding regarding the coronary arteries?
    (1) The left coronary artery arises from the right coronary sinus.
    (2) The left coronary artery follows an interarterial course.
    (3) The right coronary artery arises from the left coronary sinus.
    (4) Diffuse atherosclerotic calcifications in both right and left main coronary arteries.
    (5) (1) and (2) 
    (6) (2) and (3)
    (7) (1), (2), and (4)
    Explanation: The CT images show an anomalous origin of the left coronary artery from the right coronary sinus and its passage between the aorta and pulmonary artery—an interarterial course. No calcification is noted.

  3. What is the most likely cause of this coronary artery anomaly?
    (1) Congenital malformation/variant 
    (2) Acquired anomaly due to lifestyle or risk factors
    (3) None of the above
     Explanation: This condition is a congenital coronary anomaly, not acquired.

  4. What is the clinical significance of this coronary artery anomaly?
    (1) Increased risk of sudden cardiac death/cardiac arrest
    (2) Increased risk of coronary atherosclerosis
    Explanation: Particularly with exertion, interarterial AAOLCA is associated with a higher risk of SCD, especially in young individuals.

  5. What is the current consensus on intervention for this patient’s coronary anomaly?
    (1) Surgical correction even in asymptomatic cases 
    (2) Surgical correction only if the patient is symptomatic
    Explanation: Interarterial AAOLCA is considered high risk, and surgery is often recommended even in the absence of symptoms.

Findings and Diagnosis

Findings:
Chest CT angiography reveals a Stanford type B aortic dissection. The left coronary artery arises from the right coronary sinus and follows an interarterial course, passing between the aorta and the pulmonary artery.

Differential Diagnosis:

  • Anomalous aortic origin of the left coronary artery (AAOLCA) with interarterial course

  • AAOLCA with intraseptal course

  • AAOLCA with pre-pulmonic course

  • AAOLCA with subpulmonic course

  • Anomalous aortic origin of the right coronary artery (AAORCA)

Diagnosis:
Anomalous aortic origin of the left coronary artery (AAOLCA) with an interarterial course

Discussion

Anomalous Aortic Origin of the Coronary Arteries (AAOCA)

Pathophysiology and Epidemiology:

  • AAOCA is a congenital coronary anomaly.

  • It is associated with an increased risk of sudden cardiac death (SCD) and cardiac arrest.

  • The estimated prevalence is 0.1% to 0.7%.

  • AAORCA with an interarterial course is 3–6 times more common than AAOLCA.

  • However, among SCD cases, AAOLCA with an interarterial course is more frequently observed than AAORCA.

  • Strenuous physical activity is a significant risk factor for SCD in patients with AAOCA, especially in those aged 15–35 years.

    • AAOLCA with interarterial course is found in 6.3% of young adult SCD cases, while AAORCA accounts for 0.2%.

  • The exact mechanism of SCD remains unclear, but proposed theories include:

    • Ostial stenosis due to oblique origin from the aorta

    • Ostial ridge causing turbulent flow

    • Vessel spasm

    • Intussusception (telescoping of the vessel)

    • Compression of the anomalous artery between the aorta and the pulmonary artery

Clinical Presentation:

  • Often asymptomatic

  • When symptomatic, patients may report:

    • Chest pain

    • Palpitations

    • Dizziness

    • Syncope

Imaging Features:

  • Chest CT angiography clearly demonstrates the left coronary artery arising from the right coronary sinus, and in the case of an interarterial course, the vessel passes between the aorta and the pulmonary artery.

Treatment:

  • Activity restriction is generally advised.

  • In high-risk anomalies such as interarterial AAOLCA, surgical correction is recommended even if asymptomatic.

  • Stress testing and cardiology clearance are advised before engaging in competitive or high-intensity sports for low-risk anomalies (e.g., AAORCA or non-interarterial AAOLCA).

References:

  1. Brothers JA, Frommelt MA, Jaquiss RDB, Myerburg RJ, Fraser CD, Tweddell JS, et al. Expert consensus guidelines: anomalous aortic origin of a coronary artery. J Thorac Cardiovasc Surg. 2017;153(6):1440–57. doi:10.1016/j.jtcvs.2016.11.066
  2. Angelini P. Coronary artery anomalies—current clinical issues: definitions, classification, incidence, clinical relevance, and treatment guidelines. Tex Heart Inst J. 2002;29(4):271–8. PMID:12638688
  3. Cheezum MK, Liberthson RR, Shah NR, Villines TC, O’Gara PT, Landzberg MJ, et al. Anomalous aortic origin of a coronary artery from the inappropriate sinus of Valsalva. J Am Coll Cardiol. 2017;69(12):1592–608. doi:10.1016/j.jacc.2016.11.068
  4. Gräni C, Benz DC, Steffen DA, Clerc OF, Schmied C, Possner M, et al. Outcome in middle-aged individuals with anomalous origin of the coronary artery from the opposite sinus: a matched cohort study. Eur Heart J. 2017;38(25):2009–16. doi:10.1093/eurheartj/ehx174
  5. Kim SY, Seo JB, Do KH, Heo JN, Lee JS, Song JW, et al. Coronary artery anomalies: classification and ECG-gated multi–detector row CT findings with angiographic correlation. Radiographics. 2006;26(2):317–33. doi:10.1148/rg.262055062






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