What are the other Names for this Condition? (Also known as/Synonyms)

• Congenital Absence of the Pulmonary Artery
• Isolated Unilateral Absence of a Pulmonary Artery
• Unilateral Absence of a Pulmonary Artery (UAPA)

What is Unilateral Absence of the Pulmonary Artery? (Definition/Background Information)

• Unilateral Absence of the Pulmonary Artery (UAPA) is a heart defect that is present from birth. The pulmonary artery takes blood from the heart to the lungs. In the absence of a pulmonary artery, other blood vessels compensate by supplying blood to the lungs. Pressure can build inside these vessels and lead to heart and lung complications
• UAPA can be left sided or right sided. It most often occurs alone, but can occur with other heart anomalies and birth defects. Signs and symptoms include repeat lung infections, lower exercise tolerance, shortness of breath, chest pain, and fluid in the lungs
• Risk for these symptoms increase with age. Complications of UAPA include, hemoptysis (coughing up blood), respiratory hemorrhage, and high blood pressure in the arteries to the lung (pulmonary hypertension). Serious complications may be triggered by stress on the body, such as pregnancy and altitude sickness
• There is very limited data regarding long-term outcomes of treated infants with isolated UAPA. Most of the information available on this topic is individual case reports. These individual cases often report successful outcomes
• The estimated overall mortality rate across all age groups for people with UAPA and pulmonary hypertension is 7%. Infants with severe pulmonary hypertension tend to have a poorer outcome, than those whose symptoms develop later in life

(Source: Unilateral Absence of a Pulmonary Artery; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

Who gets Unilateral Absence of the Pulmonary Artery? (Age and Sex Distribution)

• Unilateral Absence of the Pulmonary Artery is a rare congenital disorder. The presentation of symptoms may occur in infancy, childhood, or adulthood 
• Both males and females may be affected
• Worldwide, individuals of all racial and ethnic groups may be affected

What are the Risk Factors for Unilateral Absence of the Pulmonary Artery? (Predisposing Factors)

• Currently, no risk factors have been clearly identified for Unilateral Absence of the Pulmonary Artery

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Unilateral Absence of the Pulmonary Artery? (Etiology)

• Unilateral Absence of the Pulmonary Artery is caused by abnormalities during early embryonic development
• The events that cause these abnormalities are not clearly understood

(Source: Unilateral Absence of a Pulmonary Artery; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

What are the Signs and Symptoms of Unilateral Absence of the Pulmonary Artery?

The signs and symptoms of Unilateral Absence of the Pulmonary Artery in infancy may include:

• Pulmonary hypertension
• Congestive heart failure

Older individuals may be asymptomatic or present with the following signs and symptoms of UAPA:

• Exercise intolerance
• Shortness of breath
• Chest pain
• Recurrent infections in the lungs
• Fluid accumulation in the lungs

How is Unilateral Absence of the Pulmonary Artery Diagnosed?

Unilateral Absence of the Pulmonary Artery is diagnosed on the basis of the following information:

• Complete physical examination
• Thorough medical history evaluation
• Assessment of signs and symptoms
• Laboratory tests
• Imaging studies
• Biopsy studies, if necessary

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Unilateral Absence of the Pulmonary Artery?

The complications of Unilateral Absence of the Pulmonary Artery may include:

• Pulmonary hypertension
• Bleeding in the lungs, causing coughing up of blood
• Severe lung infections

Complications may occur with or without treatment, and in some cases, due to treatment also.

How is Unilateral Absence of the Pulmonary Artery Treated?

Treatment options for Unilateral Absence of the Pulmonary Artery include:

• Observation (symptom-free, low risk cases)
• Surgery to improve blood flow between the heart and lung (shunting or re-connecting existing arteries to the lung)
• Surgery and/or medications to address lung complications
• Embolization (blocking-off) of dangerous blood vessels

Surgical approach is individually tailored based upon the person’s condition and anatomy. Early treatment (in infancy) can protect against late complications and improve lung development.

(Source: Unilateral Absence of a Pulmonary Artery; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

How can Unilateral Absence of the Pulmonary Artery be Prevented?

• Unilateral Absence of the Pulmonary Artery may not be preventable, since it is a congenital disorder
• Active research is currently being performed to explore the possibilities for treatment and prevention of inherited and acquired genetic disorders
• Regular medical screening at periodic intervals with tests and physical examinations are recommended. This will ensure a timely diagnosis in affected individuals who are asymptomatic 

What is the Prognosis of Unilateral Absence of the Pulmonary Artery? (Outcomes/Resolutions)

• There is very limited data regarding long-term outcomes (prognosis) of treated infants with isolated Unilateral Absence of the Pulmonary Artery. Most of the information available on this topic is individual case reports. These individual cases often report successful outcomes
• The estimated overall mortality rate across all age groups for people with Unilateral Absence of a Pulmonary Artery and pulmonary hypertension is 7%. Infants with severe pulmonary hypertension tend to have a poorer outcome, than those whose symptoms develop later in life

(Source: Unilateral Absence of a Pulmonary Artery; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

Additional and Relevant Useful Information for Unilateral Absence of the Pulmonary Artery:

The following DoveMed website link is a useful resource for additional information:

http://www.dovemed.com/diseases-conditions/rare-disorders/