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Donor: Dr. Klotz
Date: 1909
Size (H x W x D cm): 10 x 6 x 5
Abbott No 62
A red rod is seen extending from the aorta on the left through a widely patent ductus into the pulmonary artery on the right.
History: Infant born prematurely at 8 months.
Comment: The sixth aortic arch contributes the proximal portions of both pulmonary arteries. On the right side, the distal part loses its connection with the aorta and regresses; on the left, it persists as the ductus arteriosus. The latter provides an intrauterine conduit for blood to flow from the right heart to the aorta, bypassing the non-functional lungs. The ductus maintains its patency in fetal life by the action of prostaglandins produced by the placenta and the ductus itself. After birth, these mediators decrease precipitously. Combined with an increase in blood PO2, this usually results in closure of the ductus functionally within 2-3 days and anatomically within 2-3 weeks (forming the fibrous ligamentum arteriosum).
Failure of the ductus to close (patent ductus arteriosus) can result in a left to right shunt (higher pressure aortic blood flowing into the pulmonary artery) and, eventually, pulmonary hypertension. The abnormality occurs in about 8 of 1000 premature babies and 2 of 1000 full term ones. Clinical significance and complications depend on the size of the ductus lumen.