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Patent Ductus Arteriosus
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Pathophysiology
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The ductus arteriosus is part of the normal fetal circulatory system. This vessel connects the aorta and the pulmonary artery. Prior to birth the ductus arteriosus allows for antegrade flow from the right ventricle to the aorta. Following birth the ductus arteriosus normally closes. If the ductus remains open, blood will shunt from the aorta into the pulmonary artery due to the decrease in pulmonary vascular resistance. The amount of left-to-right shunting depends upon the size of the PDA and the relative resistances of the systemic and pulmonary circulations. Left-to-right shunting of blood caused by patency of the ductus arteriosus results in increased pulmonary artery blood flow as well as left atrial and left ventricular overload. Extensive aortic runoff, with low aortic diastolic pressure secondary to a large patent ductus arteriosus can result in systemic organ hypoperfusion. Pulmonary vascular obstructive disease may occur, sometimes as early as one year of life.
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Surgical Technique
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Surgical technique may vary, but closure of isolated patent ductus arteriosus is most often performed through a left posterior thoracotomy. The PDA is isolated and either ligated or divided. Special care must be exercised in order to avoid damage to the recurrent laryngeal branch of the vagus nerve which courses around the patent ductus. A chest tube may be placed prior to chest closure.
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Postoperative Considerations
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The postoperative course following closure of isolated patent ductus arteriosus is usually benign. Length of hospital stay following repair may be as short as two days. Longer hospital stay is sometimes required in patients who present as premature infants or who are in significant congestive heart failure preoperatively. Invasive monitors and vasoactive infusions are rarely required for postoperative management.
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