Echocardiographic Diagnosis ofThrombus Originating from the Ductus Arteriosus Luciana T. Pagotto, MD, Lloyd Y. Tani, MD, Elizabeth Raetz, MD, Edwin C. McGough, MD, and L. LuAnn Minich, MD, Satt Lake City, Utah Initial functional c10sure of the ductus arteriosus normally occurs within hours after birth, with permanent c10sure taking several weeks. The mechanism for ductal c10sure has been well studied and has not been shown to inc1ude thrombus formation. We describe a normal infant found to have a thrombus originating in the ductus arteriosus that occ1uded the ductus and CASEREPORT A term male infant, weighing 3.7 kg, was first seen for eval- uation of cyanosis that developed several hours after deliv- ery. Pregnancy and delivery were uncomplicated. Apgar scores were 6 at 1 minute and 8 at 5 minutes. Results of routine obstetric ultrasonography (performed at 20 weeks' gestation) were normal. I Family history was negative for hypercoagulability disorders. Physical examination was remarkable for mild cyanosis and tachypnea, a grade 1I/V1 systolic murmur, and hepatomegaly. A ehest radiograph showed mild cardiomegaly with decreased pulmonary vas- cular markings and clear lung fields. Because cyanotic con- genital heart disease was suspected, an infusion of prosta- glandins EI was started. An echocardiogram revealed normal intracardiac anatomy with right-to-Ieft shunting at the atriallevel and a homoge- neous 100mm x 5-mm mass originating in the ductus arte- riosus with complete occlusion of the ductus (Figure 1). Although the mass extended into the main pulmonary artery, no significant stenosis was found by Doppler. A complete hematologic evaluation was performed to rule out a hypercoagulability disorder. Protein C, protein S, antithrombin 111, and homocysteine levels were all normal. Additionally, DNA-based testing showed no evidence of the factor V Leiden mutation. Low-molecular-weight heparin was started at 1.5 mg/kg subcutaneously every 12 hours From the Departments of Pediatrics and Surgery, Primary Children's Medical Center, and the University ofUtah, Salt Lake City. Reprint requests: Luciana T. Pagotto, MD, Primary Children's Medical Center, 100 N Medical Drive, Salt Lake City, UT 84113. Copyright © 1999 by the American Society ofEchocardiography. 0894-7317/98/$8.00 + 0 27/4/94512 subsequently extended into the left pulmonary artery, threatening to occ1ude it as well. This case illustrates the importance of echocardiography in making this rare diagnosis. It also emphasizes the role of echocardiography as an effective means of following the progression or regression of such a thrombus. (J Am Soc Echocardiogr 1999; 12:79-81.) with antifactor Xa levels used to monitor the efficacy of anticoagulation. A repeat echocardiogram performed 4 days after initiation of anticoagulation revealed no change in the size of the mass but new extension of echogenic strands into the main pulmonary artery. Color and pulsed wave Doppler interrogation showed no obstruction to flow within the pulmonary vessels. The infant remained stable but had a persistent supple- mental oxygen requirement. At 9 days of age, a new sys- tolic murrnur was heard localized to the left upper sternal border. Tbe findings from a lung perfusion scan were nor- mal. The change found during the cardiac examination prompted the performance of an additional echocardio- gram. The results showed further extension of the mass into the main pulmonary artery, causing partial obstruc- tion of the orifice of the left pulmonary artery. Doppler evaluation showed turbulence in the left pulmonary artery with an increased velocity to 1.75 m/s. Echogenie strands also were seen extending from the medial aspect of the thrombus toward the right pulmonary artery. Because the thrombus was enlarging despite adequate anticoagulation and was threatening occlusion of both branch pulmonary arteries, the infant underwent pul- monary artery thrombectomy and ligation of the patent ductus arteriosus. Direct surgical inspection revealed a thrombus originating from the site of the ductus with strands extending into both branch pulmonary arteries. The mass was removed, and histologie evaluation showed areas of fibrin, red blood cells, microcalcifications, and multinucleated giant cells. The postoperative course was uncomplicated, and the oxygen requirement and murrnur were resolved. The infant was discharged on the fourth postoperative day receiving subcutaneous low-molecular- weight heparin to prevent further clot formation. 79