What is unifocalization?
Unifocalization is a surgery that brings together abnormal pulmonary arteries into a single, functioning pulmonary artery system. Our pulmonary artery reconstruction team at Boston Children’s is among the few in the world to offer the procedure.
Treating MAPCAs with unifocalization surgery and cardiology care
Our heart team’s specialized care of the rare condition tetralogy of Fallot with MAPCAs reduces the number of operations an infant needs and improves their heart and pulmonary health.
What does unifocalization treat?
Unifocalization treats a rare and serious type of congenital heart disease known as major aortopulmonary collateral arteries (MAPCAs). MAPCAs are most commonly part of an extreme form of the heart condition Tetralogy of Fallot (ToF) with pulmonary atresia.
When a child has MAPCAs, their pulmonary valve is either blocked or missing. MAPCAs form in utero to help deliver blood to the lungs. They are often tiny — one millimeter or smaller in diameter — and after a child is born they become an unreliable source of blood to the lungs. Typically, MAPCAs must be treated within the first several months of life.
This front view of an illustrated heart shows foundational cardiovascular structures: the left atrium (LA) and right atrium (RA), left ventricle (LV) and right ventricle (RV), and aorta. It also shows what happens when a child has the complex congenital heart defect tetralogy of Fallot (ToF) with pulmonary atresia and major aortopulmonary collateral arteries (MAPCAs). Several MAPCAs extend from the aorta and branch off around the left pulmonary artery and toward the right side of the heart. Meanwhile, an overriding aortic valve extends over a ventricular septal defect that’s often associated with ToF.
How does unifocalization treat MAPCAs?
In a procedure that can last as long as 20 hours, our cardiac surgeons bring together MAPCAs and a child’s natural pulmonary arteries, reconstructing them into a single, functional pulmonary artery system.
What to know about MAPCAs treatment
There are four things every parent should know about MAPCAs treatment, according to Hannah’s parents. They just saw her get specialized care for the rare cardiovascular condition and are happy she got healthy in time for her first birthday.
What are the benefits of unifocalization?
Before unifocalization was developed, treatment for ToF and pulmonary atresia with MAPCAs frequently required several surgical procedures. Operations included one to connect the right ventricle to the pulmonary artery, while additional operations attached the MAPCAs to the natural pulmonary arteries. Only after all of the vessels were treated would a patient possibly be considered for closure of the ventricular septal defect (VSD), which is associated with ToF. Fortunately, the creation of the specialized unifocalization surgery has shortened the treatment process to only one or two procedures.
This front view of an illustrated heart shows how unifocalization surgery combines major aortopulmonary collateral arteries (MAPCAs) and natural pulmonary arteries to create a single functioning pulmonary artery system. As part of that reconstruction, homograft patches are used to improve blood flow in the natural arteries and MAPCAs. Also, a right ventricle (RV)- to pulmonary artery (PA)-conduit stabilizes blood flow after a ventricular septal defect (VSD) patch is applied. The illustration also shows the left atrium (LA) and right atrium (RA), left ventricle (LV) and right ventricle, left pulmonary artery, and aorta.
During unifocalization, the surgical team performs a unique test known as an interoperative flow study to confirm whether the pulmonary vascular network will be able to handle closure of the VSD. If the arteries can’t handle enough blood flow to allow the VSD to be closed, the VSD is left open and a connection between the right ventricle and pulmonary artery is created. (Additional cardiac catheterizations may be performed on that connection.) Typically, if a child is unable to have the VSD closed at the initial operation, it can be closed six months later with the placement of a larger right ventricle-to-pulmonary artery conduit. Like unifocalization itself, Boston Children’s is one of the few pediatric heart centers that performs the interoperative flow study.
How do cardiology interventions help with care?
Our cardiologists have a key role in the care of children who have ToF and pulmonary atresia with MAPCAs. After a diagnosis, cardiac catheterization helps our cardiologists evaluate a child’s MAPCAs and natural pulmonary arteries in detail, including assessing pressures in the vessels and determining whether there are regions of narrowing (stenosis).
After the unifocalization operation, cardiac catheterization continues to help with care by rehabilitating pulmonary arteries. Rehabilitation procedures may involve balloon dilation or the placement of stents to help vessels grow and improve blood flow to the lungs. The procedures may also prepare the VSD for its eventual closure or to ensure that right ventricular pressure remains low after the VSD is closed.
Our pulmonary artery reconstruction team is one of the world’s most experienced in treating ToF and MAPCAs. We provide individualized, lifelong care to maximize a child’s heart and lung function and help them grow.
