Percutaneous major aortopulmonary collateral artery banding using a covered stent in an infant

Abstract

We report a 6-month-old infant with pulmonary atresia with ventricular septal defect who was successfully treated with a novel technique of percutaneous major aortopulmonary collateral artery (MAPCA) banding with a covered stent. He suffered from heart failure due to a residual MAPCA of 4.5 mm in diameter. A covered stent tied with 2 5–0 size nylon threads was successfully deployed into the MAPCA in a dumbbell shape with a banding diameter of 2.8 mm. Banding covered stent implantation is a useful method to reduce the pulmonary blood flow in patients with MAPCA, which could be a less-invasive alternative to surgery.

A male infant was prenatally diagnosed with PA (pulmonary atresia) /VSD (ventricular septal defect) /major aortopulmonary collateral arteries (MAPCAs) and treated at our institution.

CASE REPORT

A male infant was prenatally diagnosed with PA (pulmonary atresia) /VSD (ventricular septal defect) /major aortopulmonary collateral arteries (MAPCAs) and treated at our institution. He had 3 non-stenotic bilateral MAPCAs with no intrapulmonary connections. Since there was no central pulmonary arterial bifurcation, he underwent central unifocalization with placement of RVOT conduit at the age of 6 months. However, it was difficult to find the right MAPCA, which was deep behind the heart. Postoperatively, he developed transient malignant hyperthermia followed by severe heart failure with pulmonary overflow. The catheterization 1 month after surgery showed the right MAPCA of 4.5 mm in size originating from the descending aorta with a large amount of blood flow. Since the surgery was highly invasive, and there was concern about recurrent malignant hyperthermia, we decided to percutaneously control the flow of the MAPCA.

We used a covered stent (GRAFTMASTER™ RX, Abbott Vascular): a stainless-steel stent covered with ePTFE membrane. Fig. 1 shows the banding and deployment procedure for it. We tied the stent with 5–0 nylon threads around a 2.8-mm balloon (Fig. 2a). The tied stent was remounted and crimped on a 5-mm non-compliant balloon (NC Coyote™, Boston Scientific). An 8.5-Fr guiding catheter (Parent Plus 60, Medikit, Tokyo, Japan) was positioned to the right MAPCA via the left femoral artery. The prepared “banding” stent was delivered and deployed as proximal as possible so as not to interfere with unifocalization in the next surgery (Fig. 2b). The stent was successfully implanted in a dumbbell shape (Fig. 2c). The tied site of the stent was just 2.8 mm as targeted (Fig. 2d), while the stent's ends were expanded to 5.0 mm. The pressure of the right MAPCA decreased from 80 to 50 mmHg. The level of SpO₂ decreased to 85% and the symptoms of heart failure improved. He discharged without any complications 1 month later and is doing well for 1 year after the intervention without in-stent stenosis in the MAPCA.

Figure 1:

The schemas show the procedure of the preparation and deployment of the banding covered stent. Step 1: a covered stent that was detached from premounted balloon was banded using 2 5–0 size nylon threads. It sewed 3 points around the centre of it with running stitching to prevent migration of the threads during its delivery. Subsequently, the threads were fastened during the 2.8-mm balloon, which the stent mounted was fully inflated. Step 2: the stent banded with the threads was remounted and crimped on a 5-mm non-compliant balloon. Finally, the remounted balloon was inflated at the target site and the stent was successfully implanted in a dumbbell shape. The banding diameter in the center of the stent was just 2.8 mm as targeted.

Figure 2:

(a) The prepared covered stent. We inflated the remounted 5-mm balloon (b) and the stent was successfully implanted in a dumbbell shape (c). The banding site of the stent was exactly 2.8 mm (arrowhead) as targeted (d).

DISCUSSION

Mollet et al. [1] reported an animal study that demonstrated the effectiveness of a transcatheter pulmonary artery banding device. Nevertheless, to date, there is no clinical application of this unique method. Our method was based on previous reports on the closure of a large venous connection and congenital portosystemic shunt [2, 3]. Other reports described flow reducing stents for the portosystemic shunt in adults [4, 5]. However, these techniques using the off-the-shelf devices were not practical in infants with small vessels and a tailored approach is needed. Fanelli et al. [4] banded the balloon on which the stent was mounted. In the present case, we banded not the balloon but the stent itself so that it would be dumbbell-shape with accurate target size. It also prevents the balloon from being stuck when withdrawing it into the catheter after stent deployment. Besides, to prevent the thread migration during the stent delivery, 3 points around the center of the stent were sutured with a running stitch. In our technique, if the banding diameter is too tight, the balloon may be trapped when we withdraw it. Therefore, we cautiously determined the adequate diameter of the banding site. These efforts allowed us to successfully implant the banding stent with the exact position and diameter as targeted. This method of banding covered stent implantation could be a less-invasive alternative to surgical banding procedure even in infants.