Rebuilding Children's Hearts: Norwood Procedure Survival Rates Best in the US

A few times a month, Medical College of Wisconsin surgeons begin the long process of reconstructing the heart of an infant born with part of the vital organ that's either too small or not there at all.

The first step in treating the often-fatal defect is the Norwood procedure, and physicians in the Medical College Children's Specialty Group have refined the surgery and related monitoring to the point where they publish survival rates that are the highest in the US and among the highest in the world.

"The Norwood procedure is the first in a series of three operations that are designed for palliation or intervention for a very complex, serious congenital heart lesion called hypoplastic left heart syndrome," said Stuart Berger, MD, Medical College Professor and Chief of Pediatric Cardiology who practices at the Children's Hospital of Wisconsin Herma Heart Center.

"That is a type of cardiac abnormality where essentially the majority of the left side of the heart is either missing or is too small to support the circulation," said Dr. Berger. "The three operations over a period of several years are designed to reconstruct the heart so that the heart can work as a single ventricle. Up until several years ago, the success rate for Norwood palliation was much less than it currently is. This is the case for most, if not all institutions.

"In fact, up until the early 1990s, if you were born with this abnormality it was essentially a sentence of death."

Supplying the Body with Blood
Typically, infants treated with the Norwood procedure go into the operating room at about 7:00 a.m. and come back to the Intensive Care Unit in the early afternoon, Dr. Berger said. The actual reconstructive portion of the surgery itself takes about one to two hours.

"What is done during the first procedure is a reconstruction of the aorta using the native proximal pulmonary artery augmented by homograft tissue," said Dr. Berger. This reconstruction incorporates the native aorta and is carried out all the way down to the descending aorta. "Blood flow must also be supplied to the lungs. Therefore a shunt is provided to the lungs, either via a connection from the innominate artery to the pulmonary artery or via a connection from the right ventricle itself.

"What is accomplished is a reconstruction of the heart so that a single ventricle, the right ventricle, will then be able to pump into an unobstructed aortic outflow as well as provide blood flow to the lungs. There have been many innovations in the surgical technique and in the postoperative care of these infants. These modifications and innovations in therapies have contributed to the much better success rate."

Success Rate Now Over 93%
The innovations developed at the Medical College, Dr. Berger said, include the surgical techniques, new drugs used in the operating room, and enhancements in the way that the infants are monitored in the operating room and in the immediate post-operative period, as well as after they are discharged from the hospital.

"All of these innovations, many of which have been piloted here, have resulted in our institution having a success rate that is probably the best in the country and maybe the best in the world right now," said Dr. Berger. "Traditionally, maybe ten years ago, good success was 70% survival for this abnormality. At our institution over the last seven or eight years we have achieved a 93-plus percent survival.

"There are three stages of surgical intervention. The first operation is done at birth, the second operation is done typically around 4 to 6 months of age, and the third operation is typically done at about 2 to 4 years of age. But up until recently, even if the infant made it to hospital discharge, there was a 15% to 20% mortality while at home and prior to the second stage operation."

Home Monitoring Enables Intervention
Dr. Berger credits the home monitoring program for hypoplastic left heart syndrome patients, instituted by the Medical College and Children's Hospital, for playing a big role in getting infants from discharge after stage one to the stage two operation with minimal to no mortality.

"Monitoring infants at home after the Norwood operation allows us to detect abnormalities that may alter oxygen saturation or growth. These alterations may involve either a progressive anatomic abnormality of the heart or an acquired abnormality such as a viral infection. Either can potentially be life-threatening in this population of patients.

"Early detection by the monitoring of oxygen saturation and growth at home can allow for early intervention, thereby preventing a catastrophic event from occurring. This approach has reduced the interstage mortality (between the first and second operations) to near zero and is currently being adopted by other institutions," said Dr. Berger. In addition, he noted, the success rate for the second operation was close to 100%. Therefore the most vulnerable period of time for this group of patients is after the first stage operation up until the second stage of repair.

Generally, all infants born with hypoplastic left heart are candidates for the Norwood procedure. Dr. Berger said it is very rare for an infant to have risk factors that preclude the surgery or would make them better served by heart transplant, estimating that more than 95% of the infants diagnosed with the abnormality would get this intervention.

Treating Kids from Around the Country
"We perform the Norwood operation here between 20 and 30 times per year," said Dr. Berger. "Our outcomes have been recognized outside the institution, so we're now seeing infants with this abnormality from all over the country. We've taken care of infants and families from Illinois, Colorado, Florida, and Georgia. So the word is out as people look on the Internet and physicians read the literature. Our approach in Milwaukee, with the use of innovative medications, newer methods of intra-operative and post-operative monitoring, and out-of-hospital home monitoring have all been major reasons for our success.

"I am very fortunate to work with a group of people who have been at the cutting edge of innovation and dedication in the care of this group of patients. The talented group of people led by Dr. James Tweddell, Dr. George Hoffman and Dr. Nancy Ghanayem has pioneered techniques and has spent countless hours at the bedsides of this complex group of infants. This is complemented by the cooperative multi-disciplinary approach to care of these infants that includes the input of nurses, nurse practitioners, intensivists, surgeons, physician assistants, anesthesiologists, cardiologists, neonatologists, respiratory technologists, etc. Their hard work, dedication, innovation, and collaboration have allowed us to achieve great outcomes."

Dan Ullrich
HealthLink Contributing Writer

MCW Health News presents up-to-date information on patient care and medical research by the physicians of the Medical College of Wisconsin.