The snare-assisted technique for transcatheter coil occlusion of moderate to large patent ductus arteriosus: immediate and intermediate results
Frank F. Ing, MD, FACC* and
Robert J. Sommer, MD
* Department of Pediatric Cardiology, Baylor College of Medicine, Texas Children’s Hospital, Houston, Texas, USA
Department of Pediatric Cardiology, Mount Sinai School of Medicine, Mount Sinai Medical Center, New York, New York, USA
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Figure 1 A descending aortogram in lateral projection demonstrates a type A patent ductus arteriosus (PDA) with a minimum diameter of 3.1 mm located just anterior to the tracheal air column (between white arrows). This air column is highlighted in Figures 1 through 6 with white arrows and serves as an important reference landmark for coil positioning. A catheter with a 10-mm marker is placed in the main pulmonary artery (MPA) for measurement references. (AoD = descending aorta.)
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Figure 2 A 1/4 loop of the coil is extruded out of the Berenstein catheter. The snare is loosened and withdrawn gently so that it slides off the catheter onto the "hook" of the loop to snare the coil. To minimize entanglement with Dacron fibers on the coil, no more than 2 to 3 mm of the coil tip should be snared. White arrows = tracheal air column.
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Figure 3 The snare–coil–Berenstein unit is adjusted so that only the proximal coil tip is in the main pulmonary artery and the rest is in the descending aorta. The entire coil is then delivered out of the Berenstein into the descending aorta, and the coil loops reform within the aortic ampulla and descending aorta. The tracheal air column (between white arrows) is critical for proper coil delivery.
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Figure 4 The coil position is adjusted by placing gentle traction on the snare. Note this maneuver results in wedging of the coil into the conical shaped ampulla for better occlusion. Comparing the coil position to the tracheal air column in Figure 3, note also the coil has been pulled more anteriorly by the snare. The first proximal loop (solid white arrowhead) is oriented parallel to the segment of the ductus that contains the minimum diameter as it enters the pulmonary artery. The horizontal alignment of the proximal coil loop to the ductus increases its occlusive abilities. The most distal coil loop (open arrowhead) maintains a perpendicular alignment to the ductus inside the aortic ampulla and will prevent the coil from embolizing through the ductus into the main pulmonary artery. White arrows = tracheal air column.
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Figure 5 Once the coil position is optimal, injection of contrast medium through the Berenstein catheter immediately after coil implant is useful to assess residual shunting and to confirm coil position in relationship to the pulmonary artery and aortic ampulla before snare release. White arrows = tracheal air column.
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Figure 6 Coil is released from snare. Note only 1/4 coil loop is used to anchor the coil in the main pulmonary artery side, minimizing any risk of impingement of left pulmonary artery flow. White arrows = tracheal air column.
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Figure 7 Final descending aortogram to evaluate for residual shunting. Note the snare-assisted technique in coil delivery has permitted most of the coil to be placed on the aortic side where it participates in occlusion.
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Figure 8 (A) Four coils of different dimensions. A, 0.035-in. (0.089 cm) gauge, 4-cm length, 3-mm diameter; B, 0.038-in. (0.097 cm) gauge, 5-cm length, 5-mm diameter; C, 0.038-in. (0.097 cm) gauge, 10-cm length, 8-mm diameter, D, 0.038-in. (0.097 cm) gauge, 8-cm length, 10-mm diameter. Notice the centers of the 3- and 5-mm diameter coils are completely covered by Dacron fibers. In contrast, the centers of the 8- and 10-mm diameter coils are incompletely filled by Dacron fibers, and one can see through them (arrows). (B) Side view of the four coils. Note the smaller coils are more compact compared with the larger coils, which have a much larger side profile and can result in coil protrusion into the aorta or pulmonary artery.
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