Discussion

Patent ductus arteriosus device closure in smaller children, including premature infants, has been an area of research, as traditional devices were too large for these patients. In January 2019, the Food and Drug Administration approved the Amplatzer Piccolo™ Occluder (Abbott, Abbott Park, Illinois, United States of America). This device was designed for closure of patent ductus arteriosus in premature infants weighing more than 700 g and over 3 days of age. Although traditional surgical ligation of the patent ductus arteriosus via a left thoracotomy has a very high success rate, it is associated with potential complications such as pneumothorax, bleeding, vocal cord palsy, and chylothorax. Long-term sequelae such as scoliosis and restrictive lung disease have been reported. Percutaneous patent ductus arteriosus closure is not only associated with a more rapid improvement in respiratory status compared to surgical ligation but is also less likely to develop post-ligation syndrome. ^{Reference Ogando, Asensio, Sanchez de la Blanca and Martı2} Percutaneous device placement would seem to be a favourable alternative to surgical ligation in light of these potential risks. ^{Reference Sathanandam, Dalduf and Chilakala3}

A recently published prospective multicenter study of 200 patients, including 100 patients <2 kg showed that the Piccolo device could be used safely in infants >700 g. ^{Reference Sathanandam, Gutfinger and Brien1} Left pulmonary artery stenosis has been described in patients immediately after implantation. A prospective review of patients who had undergone device closure of patent ductus arteriosus with the Amplatzer Piccolo Occluder showed that device deformation and left pulmonary artery obstruction was a common complication occurring in 8 of the 14 patients. Three infants developed obstruction (“coarctation”) of the aorta all of which resolved gradually with time. These were believed to be due to oversizing of the device. ^{Reference Chien, Wang and Lin4} The cases of mild “coarctation” did not translate into clinical significance. Recently there have been reports of neo-coarctations following placement of this device, most are self-resolving but there has been a report of at least one case requiring surgical intervention. ^{Reference Malekzadeh-milani, Akhavi, Douchin and Dauphin5,Reference Tomasulo, Munson and Dori6}

The Piccolo is designed for both the pulmonary and aortic ends of the device to be positioned in the ductus itself for patients below 2 kg; in patients above 2 kg this is not the case. The Piccolo device is made of Nitinol which is a Nickel−Titanium alloy with elasticity and memory. The elasticity allows the device to fit through a small calibre long sheath and the memory allows it to reform in its original shape when it comes out of the long sheath. On review of the angiograms, it seems like the device was under more compression than usual, and over time, the device tried to regain its native shape. Since the patent ductus arteriosus was closed, the only place for it to expand was into the aorta. The authors hereby acknowledge that the device used was oversized for the patient. It is important to note that in the current era, many operators deviate from the Amplatzer size charts (Fig 6) based on personal experience with these devices. In this case, the interventionalist’s choice of device was guided by manufacturer representative and visiting proctor.

Figure 6.

Amplatzer Piccolo sizing chart (Year 2020).

Had a smaller device been used as predicted by either the <2 kg or the >2 kg manufacturer sizing charts, it seems this complication would have been unlikely to happen. There are some important lessons learnt from this case. Embolisation of Piccolo devices occurs more frequently in patients > 2 kg. ^{Reference Sathanandam, Gutfinger and Morray7} Careful selection of device based on patient’s dry weight is important. The decision of intra or extra ductal placement of the device depends on the patient’s weight. A smaller, longer device was indicated in this case and oversizing does not prevent complications. A combination of high quality transthoracic echocardiography and angiographic appearance and lie of device during placement should guide decision to release device. In patients above 2 kg an aortogram should be performed if there is any doubt about device position. Early retrieval of device should be undertaken if the appearance of the device is not favourable.

The Piccolo device has revolutionised management of the small infant with patent ductus arteriosus but it is not without risk. This case is intended to draw the attention of cardiologists to the risk of aortic migration. Should the device be oversized for the patient.