Dilatation of the Pulmonary Artery, Idiopathic

National Organization for Rare Disorders, Inc.

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It is possible that the main title of the report Dilatation of the Pulmonary Artery, Idiopathic is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.


  • IDPA

Disorder Subdivisions

  • None

General Discussion

Idiopathic dilatation of the pulmonary artery (IDPA) is a rare congenital defect characterized by a wider than normal main pulmonary artery in the absence of any apparent anatomical or physiological cause.


Idiopathic dilatation of the pulmonary artery commonly does not produce symptoms because there is no circulatory abnormality. Clinical signs are minimal, and usually consist of a palpable pulmonary ejection sound that disappears when the patient inhales, a soft pulmonary ejection systolic murmur (abnormal heart sound), and splitting of the second sound on breathing in. IDPA does not cause pulmonary valve disease, nor does bacterial endocarditis occur in patients with this condition. The electrocardiogram is normal, and diagnosis is made when chest X-rays reveal a dilated pulmonary artery without cardiac chamber enlargement.


The cause of idiopathic dilatation of the pulmonary artery is unknown. A defect in the normal development of pulmonary artery elastic tissue before or after birth has been postulated. The dilatation may also be a consequence of a generalized connective tissue disease as it is occasionally found in Marfan's syndrome or Ehlers-Danlos syndrome. (For more information on these disorders, choose "Marfan" and Ehlers-Danlos" as your search terms in the Rare Disease Database.

Affected Populations

The incidence and prevalence of IDPA are not known. Because the disorder is benign in most instances, neither clinicians nor epidemiologists are able to measure the distribution of the disease with confidence.

Standard Therapies

Treatment for idiopathic dilatation of the pulmonary artery is not required. People with this condition have a normal life expectancy, provided they have no cardiac lesions.

Investigational Therapies

Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.

For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:

Tollfree: (800) 411-1222

TTY: (866) 411-1010

Email: prpl@cc.nih.gov

For information about clinical trials sponsored by private sources, contact:




Mesquita SM, Castro CR, Ikari NM, et al. Likelihood of left main coronary artery compression based on pulmonary trunk diameter in patients with pulmonary hypertension. Am J Med. 2004;116:369-74.

Ring NJ, Marshall AJ. Idiopathic dilation of the pulmonary artery. Br J Radiol. 2002;75:532-35.

Hoeffel JC. Idiopathic dilation of the pulmonary artery: report of four cases. Magn Reson Imaging 2001;19:761.

Ugolini P, Mousseaux E, Sadou Y, et al. Idiopathic dilation of the pulmonary artery: report of four cases. Magn Reson Imaging. 1999;17:933-37.

McLaughlin VV, Genthner DE, Panella MM, et al. Reduction in pulmonary vascular resistance with long-term epoprostenol (prostacyclin) therapy in primary pulmonary hypertension. N Engl J Med. 1998;338:273-77.


Idiopathic dilation of the main pulmonary artery - nd. 1p.



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