Interrupted Aortic Arch: Symptoms, Types, Causes and Treatment

Interrupted aortic arch (IAA) is a rare but serious congenital cardiovascular disorder that disrupts the normal flow of blood from the heart to the rest of the body. Most often diagnosed in infancy but occasionally identified in adults, IAA can present with a wide range of symptoms and is frequently associated with other heart defects. Understanding its symptoms, types, causes, and treatment options is critical for timely diagnosis, effective management, and improving outcomes for patients. This article provides a comprehensive overview, synthesizing current scientific literature to guide both patients and clinicians through the complexities of interrupted aortic arch.

Symptoms of Interrupted Aortic Arch

Interrupted aortic arch can present with a variety of symptoms, which may differ depending on the patient’s age and associated anomalies. In neonates, symptoms typically appear within the first days or weeks of life, while in rare adult cases, the presentation may be subtler or linked to complications arising from long-standing vascular changes.

Symptom	Description	Age Group	Source(s)
Heart Failure	Rapid breathing, poor feeding, lethargy, sweating, cyanosis	Neonates/Infants	7 13 15
Differential Pulse/Blood Pressure	Weak/absent lower limb pulses, higher blood pressure in arms	All Ages	1 7 9
Lower Limb Edema	Swelling of the legs due to poor circulation	Adults	1
Respiratory Distress	Shortness of breath, cough, increased work of breathing	Neonates/Adults	1 10 13

Table 1: Key Symptoms

Presentation in Infants

In neonates, IAA is a critical ductus-dependent congenital heart defect. The patent ductus arteriosus (PDA), a normal fetal blood vessel, temporarily provides blood flow to the descending aorta. As the PDA closes after birth, symptoms rapidly worsen:

• Congestive heart failure: Infants develop rapid breathing, poor feeding, lethargy, sweating, and sometimes cyanosis (bluish skin) as blood flow to the lower body is compromised. Heart failure is often the predominant feature 7 13 15.
• Differential pulses and blood pressure: There may be a noticeable difference in pulse strength and blood pressure between the arms (stronger) and legs (weaker or absent), since blood flow to the lower body is interrupted 7 9.

Presentation in Adults

While exceedingly rare, some individuals with IAA survive into adulthood due to extensive collateral blood vessels developing over time. In these cases:

• Lower limb edema may develop due to chronic poor circulation in the legs 1.
• Hypertension (high blood pressure) in the upper body, with weak or absent pulses in the lower limbs, may be the only clue 1.
• Respiratory symptoms such as cough and shortness of breath can also occur, especially if heart failure develops or if collateral vessels are insufficient 1.

Associated Symptoms

• Symptoms from associated defects: IAA is frequently linked to other congenital heart abnormalities such as ventricular septal defects, patent ductus arteriosus, or truncus arteriosus, which can add to the clinical picture and severity of symptoms 7 9 10 13.
• Ductal shock: Sudden closure of the ductus arteriosus can result in a life-threatening collapse (ductal shock), particularly in neonates 10.

Types of Interrupted Aortic Arch

The classification of IAA is based on the anatomical location where the aortic arch is interrupted. Understanding the types is crucial for diagnosis, surgical planning, and prognosis.

Type	Site of Interruption	Frequency	Source(s)
Type A	Distal to the left subclavian artery	~30%	3 7
Type B	Between the left common carotid and left subclavian arteries	~55%	1 3 7 10
Type C	Between the innominate (brachiocephalic) and left common carotid arteries	<5%	3 7

Table 2: Types of Interrupted Aortic Arch

Type A

• Location: The aorta is interrupted just after the left subclavian artery.
• Prevalence: Accounts for about 30% of cases.
• Associations: Often an isolated defect, less commonly associated with genetic syndromes 3.

Type B

• Location: The interruption occurs between the left common carotid and the left subclavian arteries.
• Prevalence: The most common type, found in over half of all IAA cases.
• Associations: Frequently linked to other heart defects (e.g., ventricular septal defect) and genetic syndromes, especially 22q11 deletion syndrome (DiGeorge syndrome) 1 3 7 10.

Type C

• Location: The rarest form, with interruption between the innominate (brachiocephalic) artery and the left common carotid artery.
• Prevalence: Less than 5% of all IAA cases 3 7.

Rare Variants

• Right-sided aortic arch interruption: Extremely rare, typically associated with complex congenital heart disease 2 4.
• Associated vascular anomalies: Aberrant subclavian arteries and variations in the branching pattern can complicate surgical repair 5.

Causes of Interrupted Aortic Arch

While IAA is a congenital defect present at birth, the underlying causes involve a combination of genetic, embryologic, and possibly hemodynamic factors.

Cause/Association	Description	Mechanism/Details	Source(s)
Genetic Syndromes	22q11.2 deletion (DiGeorge syndrome)	Affects neural crest cell migration; strong Type B link	3 10
Embryologic Flow Imbalance	Reduced flow through fourth aortic arch segments	Disappearance of key vascular connections during development	8 11
Associated Heart Defects	VSD, PDA, Truncus arteriosus	Often co-occur; may share developmental mechanisms	7 9 10
Sporadic (Unknown)	No clear cause in some cases	May represent isolated developmental error	6

Table 3: Causes and Associations

Genetic Factors

• 22q11.2 deletion syndrome (DiGeorge syndrome): This chromosomal deletion is strongly associated with Type B IAA. The syndrome affects genes critical for neural crest cell migration, which is essential for proper cardiovascular development. The association is less clear with Type A IAA 3 10.
• Other syndromes: Less commonly, IAA may be seen in the context of other genetic disorders, but the vast majority of cases center around 22q11.2 deletions 3 10.

Embryological Mechanisms

• Flow-related vascular development: During fetal development, the aortic arch forms from several paired embryonic vessels. Disruption in blood flow through these vessels (especially the fourth aortic arches) can result in their regression or failure to form, leading to interruption 8 11. For example:
  • Reduced flow through the left fourth arch, possibly due to other cardiac anomalies, can cause it to disappear, resulting in IAA 8.
  • Patterns of associated defects suggest that impaired or imbalanced flow early in heart development plays a crucial role 8.

Associated Cardiac Malformations

• Ventricular septal defect (VSD): Present in over 90% of IAA cases, particularly in infants 7 9.
• Patent ductus arteriosus (PDA): Almost universally present; provides life-sustaining blood flow to the lower body until it closes 7 9 10.
• Other anomalies: Truncus arteriosus, bicuspid aortic valve, and others frequently occur in conjunction with IAA, indicating overlapping developmental pathways 7 9 10.

Sporadic and Rare Causes

• In some adults with isolated IAA, no clear genetic or hemodynamic cause can be identified, suggesting the possibility of isolated developmental errors or unrecognized genetic factors 6.

Treatment of Interrupted Aortic Arch

Treatment of IAA is complex and depends on the patient’s age at diagnosis, associated anomalies, and overall health. The mainstay is surgical repair, but medical management is sometimes necessary in special cases.

Approach	Indication	Outcome/Notes	Source(s)
Surgery	Neonates/Infants, most adults	Restores aortic continuity; improves survival	11 12 13 15
Single-stage Repair	Preferred in most cases	Lower mortality, fewer late deaths	12 13
Two-stage Repair	Selected complex cases	Higher early/late mortality	12
Medical/Conservative	Adults with extensive collaterals or surgery refusal	Symptom management, risk of complications	1 6 14
Prostaglandin Therapy	Pre-op stabilization	Keeps ductus arteriosus open in neonates	13 15
Reinterventions	For residual stenosis or complications	High long-term reoperation rates	12 15

Table 4: Treatment Approaches

Surgical Management

Surgery is the mainstay of treatment for IAA. Most patients require prompt intervention soon after diagnosis:

• Single-stage repair: Preferred in modern practice for most infants. Involves direct connection (anastomosis) of the aortic segments and repair of any associated heart defects in one procedure. Associated with lower mortality compared to staged repairs 12 13.
• Two-stage repair: Sometimes used in complex or unstable patients. Higher rates of early and late mortality 12.
• Techniques: May include use of grafts, autologous tissue (such as an aberrant subclavian artery), or direct reconstruction, especially in complicated anatomical variants 5 11.

Surgical outcomes:

• Early surgical mortality has been improving, but remains significant, especially in the presence of complex anomalies (e.g., left ventricular outflow tract obstruction) 12 13.
• Long-term outcomes are generally favorable if arch continuity is restored and associated defects are repaired, but many patients require reinterventions for residual or recurrent arch stenosis, or other complications 12 15.

Medical and Conservative Management

• Prostaglandin E1 therapy: Used in neonates before surgery to keep the ductus arteriosus open, maintaining blood flow to the body 13 15.
• Medical/conservative management: In rare adult cases with extensive collateral circulation or where surgery is refused or contraindicated, conservative treatment with close monitoring may be attempted. However, this approach carries risks such as hypertension, heart failure, and aortic dissection due to abnormal blood flow patterns 1 6 14.
• Management of complications: Includes treating heart failure, managing hypertension, and monitoring for aortic dissection risk. Imaging such as CT angiography is vital for follow-up 1 14.

Long-term Considerations

• Reinterventions: Up to half of patients may require further surgery or catheter-based interventions for recurrent arch obstruction or other complications 12 15.
• Individualized care: Complex associated anomalies often necessitate tailored management strategies 15.
• Genetic counseling: Especially in cases linked to 22q11.2 deletion syndrome 10.

Conclusion

Interrupted aortic arch is a life-threatening congenital cardiovascular disorder that demands prompt recognition and specialized care. Here’s a summary of the main points covered:

• Symptoms vary by age, with heart failure and differential pulses common in infants, and hypertension/lower limb edema possible in rare adult survivors.
• Types are classified anatomically (A, B, C), with Type B most common and strongly associated with genetic syndromes.
• Causes involve genetic factors (notably 22q11.2 deletion), embryological vascular development errors, and frequently co-occurring heart defects.
• Treatment relies on early surgical repair, with single-stage approaches preferred. Medical management is reserved for special cases, particularly in adults with extensive collateral circulation.

Key takeaways:

• Early diagnosis and intervention are critical, especially in neonates.
• Lifelong follow-up is often needed due to the high risk of reintervention.
• Multidisciplinary, individualized care ensures the best outcomes for this complex condition.

By understanding the intricacies of interrupted aortic arch, clinicians and families can work together to ensure timely, effective, and compassionate care for affected individuals.