Congenital Thoracic Vascular Anomalies
Section snippets
Technique
Although infants and children are the most frequently affected by congenital vascular anomalies of the thorax, such anomalies can also be seen in adults, sometimes incidentally and as part of an examination for a totally unrelated indication. Therefore, examinations should be tailored to take into account radiation issues, need for sedation, and other indications so that that diagnosis is safe, comprehensive, and efficient. To accomplish this, those indications, along with available clinical
Embryology
Familiarity with the embryologic development of the thoracic vasculature is crucial in the proper understanding of the potential anomalies and anatomic variations. So, a brief review of this development follows, with an emphasis on the systemic and pulmonary circulations.
By the third week of embryonic development, paired angioblastic cords canalize to form endothelial tubes that quickly fuse into a single cardiac tube beginning at the cranial end. The cardiac tube elongates and develops
Truncus Arteriosus
Truncus arteriosus, also known as truncus arteriosus communis or common arterial trunk, is an uncommon congenital vascular anomaly accounting for 2% of all congenital cardiac disease.13 It is caused by failed septation of the embryologic truncus. As a result, a single vessel (the persistent truncus) receives the output of both ventricles and gives rise to the systemic, pulmonary, and coronary circulations (Fig. 1). There is a single truncal valve, usually dysplastic with a variable number of
Left Aortic Arch with Aberrant Right Subclavian Artery
Embryologically, a left aortic arch with aberrant right subclavian artery results from interruption of the right arch between the right common carotid artery and right subclavian artery. This is the most common congenital lesion of the aortic arch, occurring in 0.5% of the population,24 and is usually asymptomatic, although dysphagia has been reported (dysphagia lusoria). The aberrant subclavian artery is the last main branch artery of the aortic arch, arising at the junction with the
Idiopathic Dilatation of the Pulmonary Artery Trunk
In idiopathic dilatation of the pulmonary artery trunk, there is enlargement of the pulmonary trunk without cardiac or pulmonary conditions that would otherwise account for the dilatation. This anomaly is asymptomatic and nonprogressive, and is usually detected incidentally. The idiopathic dilatation may involve the right and left pulmonary arteries (Fig. 15).39
Absence or Proximal Interruption of a Pulmonary Artery
In proximal interruption of the right or left main pulmonary artery, the intrapulmonary vascular network continues to develop
Partial Anomalous Pulmonary Venous Return
In partial anomalous pulmonary venous return (PAPVR), one or more lobes drain into the right atrium or into one of its tributaries (eg, vena cavae, azygous vein, coronary sinus, left vertical vein). The anomalous connection to the right heart or systemic venous circulation results in left-to-right shunting that may or may not be hemodynamically significant. In the second most common type of PAPVR, the right superior pulmonary vein drains to the low superior vena cava or to the superior
Pulmonary arteriovenous malformation
PAVMs consist of direct communications between a pulmonary artery and a pulmonary vein without an intervening capillary network. These lesions occur as isolated entities or, in more than 60% of cases, in association with hereditary hemorrhagic telangiectasia. Also known as Osler-Weber-Rendu disease, hemorrhagic telangiectasia is an autosomal-dominant condition with the clinical triad of epistaxis, mucocutaneous or visceral telangiectasia, and family history of disease.57
PAVMs cause
Persistent Left Superior Vena Cava
A persistent LSVC has been reported to occur in 0.3 to 0.5% of the general population60, 61, 62 and in 4.4% of patients with congenital heart disease. It results from persistence of the left anterior cardinal vein. In the majority of cases, a right superior vena cava is also present. An anastomosis between the right and LSVC (bridging vein) is present in only 35% of cases. In 92% of individuals, the LSVC arises from the left brachiocephalic vein and travels inferiorly, lateral to the aortic
Sequestration
Bronchopulmonary sequestration consists of a portion of nonfunctioning lung parenchyma that has no communication with the tracheobronchial tree and receives its blood supply from a systemic artery. The anomaly is commonly classified as intralobar or extralobar. While some intralobar sequestrations may be congenital, most are acquired secondary to chronic inflammation and bronchial obstruction. Affected patients present during adolescence or adulthood with recurrent pneumonias. This form is the
Summary
The ability to diagnose congenital vascular thoracic anomalies has evolved tremendously in the past 20 years. Traditional methods of plain radiographs and barium swallow studies as well as invasive angiography have now been supplanted with MR imaging and MDCT, minimally invasive methods that provide superb resolution and a large field of view. Physicians involved in the performance of these studies must have a clear understanding of the large variety of arterial and venous anomalies included in
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