Amir H. Ashrafi
Newborns with the congenital heart defect patent ductus arteriosus face many potential complications such as respiratory failure, acute kidney injury, necrotizing enterocolitis and HF. But closing it has been much easier said than done.
Surgical closure has been shown to yield numerous complications, some of them severe. Closure via medical therapy can have a success rate of less than 50% in some studies and can be contraindicated in certain patients. And leaving the patent ductus arteriosus (PDA) open was a common option until clinicians realized its long-term consequences. Of the approximately 60,000 U.S. babies born premature each year, around 20% have a PDA that requires urgent closure.
However, there is now a new option that may be safer than surgical closure for patients who are not candidates for medical closure. In January, the FDA approved a transcatheter device (Amplatzer Piccolo occluder, Abbott) that is inserted via an incision in the leg and moves through the femoral vein to close the PDA.
Amir H. Ashrafi, MD, director of neonatal-cardiac intensive care at Children’s Hospital of Orange County in California, one of the first U.S. hospitals to perform procedures with the device after it was approved, spoke with Cardiology Today about the challenges faced by preterm babies with a PDA, how the device works and the prospects for patients going forward.
Question: What are the potential consequences if a PDA is not treated?
Answer: There are three major physiological consequences of a PDA. No. 1, there is a pressure load on the right ventricle and pulmonary arteries. No. 2, there is a volume load on the lungs and left ventricle. No. 3, most importantly, it leads to systemic “steal” and therefore decreased oxygen and nutrient delivery to developing organs. This is problematic for all neonates, but especially the premature neonates who are in a critical phase of development.
Q: What treatments did you use before the Piccolo device?
A: Treatments have greatly changed over the last several decades. Previously, the focus was on early closure of the duct, both through medical closure and surgical ligation. Over time, we realized that while we successfully removed the shunt, it did not necessarily improve patient outcomes. In fact, some patients experienced serious ramifications. Large, well-designed studies showed that surgical ligation increased both short-term and long-term morbidities, which was unexpected.
As a result, the field of neonatal cardiology has shifted over the last 10 to 15 years towards a more permissive approach. However, we are now beginning to realize that is not the right answer either. Interestingly, as more neonates are being discharged to home with a PDA, we have shifted the burden of this continuous ductal shunt to the pediatrician and outpatient cardiologist. Determining the appropriate intervention was a therapeutic conundrum.
Until recently, we had three therapeutic options: the permissive approach, medical closure or surgical ligation. Now for the first time there is a fourth option, catheter-based closure. This is nice because you avoid surgical morbidities such as lung manipulation, vocal cord nerve injury and complications associated with a chest wall incision. The Piccolo device resulted from a nice collaboration between physicians and industry to get the exact device we need for a select patient population.
Q: Does the device work similarly to catheter-based structural heart interventions for adults?
A: It is very similar to some of the other devices out there. However, its engineering, design, size and shape are specific to premature neonates. This has never been available to us before.
Q : Who is a candidate for treatment with this device?
A: Any infant, full-term neonate or preterm neonate who suffers from a hemodynamically significant PDA that needs closure and has either failed or is not a candidate for medical closure.
Q : What sort of results have you seen with catheter-based closure so far, and how do those compare with prior treatments?
A: The device was approved by the FDA in January 2019 and is in the early stages of launch. Prior to approval, there were a few centers that conducted clinical studies. The results at those centers were impressive and showed the device was effective in babies as small as 600 g, or approximately 1 lb. Those operators were able to close these PDAs with very few complications.
The procedure is performed entirely through a femoral venous approach as opposed to the early days in which both the femoral vein and artery were accessed. That is a huge step forward in making it feasible. When a sheath is put in the femoral vein, there is always the risk for injury or thrombosis to the vein. There is also the risk that the device could be too long and find its way into the descending aorta or the left pulmonary artery, causing coarctation or reverse coarctation. However, because of the great collaboration between physicians and industry, appropriate modifications to the device were made, and its length was reduced to as small as 2 mm, making it much less likely to encroach on the descending aorta or the left pulmonary artery. In addition, the device is exceptionally compliant and can get dislodged during deployment. However, the design enables the operator to retrieve it and retry.
Q : What are the implications for this population going forward?
A: We know that the hemodynamically significant PDA can have significant short-term and long-term morbidities for newborns. We know that those who are refractory to medical management had only one option, surgical ligation, which has been shown to potentially cause short-term and long-term problems. Catheter-based closure allows for elimination of that duct without the morbidities associated with surgery. The long-term neurodevelopment impact remains to be seen but is an outcome our team, driven by Sanjay P. Sinha, MD, is following prospectively. – by Erik Swain
For more information:
Amir H. Ashrafi, MD, can be reached at firstname.lastname@example.org.
Disclosure: Ashrafi reports no relevant financial disclosures.