Game changer

Imagine for a moment that it’s 2001, and you’re Jennifer Miller. You’re pregnant with your second baby, and an ultrasound shows that his heart isn’t developing normally: In fact, the left side of his heart has a problem so significant it will stop developing normally from that point on. Your unborn baby has a severe blockage of the aortic valve, known as stenosis, which will lead to a rare and potentially fatal condition called hypoplastic left heart syndrome (HLHS) at birth.

Now imagine that you’re Jack Miller. As you float in the quiet darkness of the womb, your heart is the size of a grape and that troublesome valve that won’t deliver blood from the left ventricle of your body is only as big as the head of a ballpoint pen.

What happened next put the Millers on the front page of the New York Times and in TIME magazine.

A star is born

An ultrasound technician noticed a problem with Jack’s heart during the 18th week of Jennifer’s pregnancy. Further testing and a more detailed ultrasound showed his aortic valve was too narrow, restricting blood flow and thus weakening the development of the left ventricle. Thankfully technicians detected it early—about half of all serious congenital heart defects, including serious defects like HLHS, are missed in ultrasounds or just discovered too late for anything to be done. But even with the advance knowledge, doctors still needed to act quickly to reverse the damage, because without treatment, the left half of Jack’s heart could inevitably stop developing, resulting in HLHS.

Jennifer and her husband Henry were devastated by the diagnosis. Kids with HLHS have anywhere from a 20 to 30 percent mortality rate depending on the severity of the condition and where care is provided, and treatment for the condition requires multiple open-heart surgeries within the first four years of life. Even after successful surgeries, they are left with a single pumping chamber in their hearts, rather than the normal two. It’s also not unusual for kids with HLHS to need a heart transplant later on in life.

But after a careful examination, doctors told the Millers that there might be another option. As it turned out, Jennifer and her unborn baby were thought to be a good match for an experimental procedure that in theory could help their child avoid HLHS by opening his heart valve while he was still in the womb.

That afternoon Jennifer and Henry met Wayne Tworetzky, MD, director of Children’s Fetal Cardiology Program and co-director of Children’s Advanced Fetal Care Center. With the help of a few hand-drawn illustrations, Tworetzky explained that he and his team could possibly correct Jack’s obstructed valve by opening it while Jack was still in the womb. This procedure would be done by inserting a 19-gauge needle (about the thickness of an uncooked piece of spaghetti) through Jennifer’s stomach, into Jack’s left ventricle, after which a tiny wire and balloon catheter would be threaded across the blocked heart valve. Once in place the balloon would be inflated, forcing the valve open and letting the blood flow freely from his left ventricle to his body, thereby helping his left ventricle grow and function more normally.

The idea of sticking a needle into such a small, moving target sounded far-fetched to the Millers at first, but the more Tworetzky described it, the clearer it became that this was the right choice.

Wayne Tworetsky, MD

“We knew this [kind of fetal intervention] had never been done with the desired outcome, and that the amount of planning and precision it required from the surgical team was mindboggling,” says Jennifer. “But we had faith in the teams from Children’s and Brigham and Women’s. We focused on the fact that if it was successful it would give Jack a better shot at life. That kind of payoff was so huge we knew that we wanted to undergo the risks, even though they were so substantial.”

On September 13, 2001 — under the watch of Boston Children’s Cardiologist-in-Chief James Lock, MD — Tworetzky, fetal surgeon Russell Jennings, MD, and cardiologists Stanton Perry, MD, and Audrey Marshall, MD, joined Brigham and Women’s experts Louise Wilkins-Haug, MD, PhD, and Carol Benson, MD, in the surgical suite.

To begin, Wilkins-Haug massaged Jennifer’s stomach, coaxing the fetus into an ideal position for the intervention. Once aligned, Jennings held the fetus in place, giving Wilkins-Haug time to insert the needle into Jennifer’s abdomen, guiding it towards the fetal heart using ultrasound images being monitored by Tworetzky and Lock.

Time is a crucial factor in any fetal intervention, so the team worked quickly to reach its target. Wilkins-Haug made contact with the valve, thereby setting the stage for Dr. Perry and Dr. Marshall. Working in tandem, the cardiologists threaded and inflated the tiny balloon across the valve, opening it and letting substantially more blood to flow from the left ventricle to the aorta and the body.

“When I woke up everyone in the room was elated and anxious to show me the echocardiogram,” remembers Jennifer. “It was a little overwhelming at first, I was coming out of anesthesia and didn’t have my glasses on, but seeing those tiny digitalized spurts of blood pass through his heart confirmed everything. It was beyond thrilling.”

Two months later Jennifer and Henry welcomed their son into the world. Weighing 5 lbs. and 8 ounces, initial echocardiograms confirmed what the Miller’s and their medical team had been hoping for: Thanks to the fetal cardiac intervention, baby Jack was born healthy with a typical, four-chambered, two-ventricle heart.

Replicating success

Ten years ago, the care team’s accomplishment landed baby Jack in the midst of national headlines. He’ll always be remembered as the procedure’s first success story, and he’s certainly paved the way for others. Since 2001, Jack’s medical team has done more than 140 fetal cardiac interventions — more cases than the combined total of every other hospital in the world.

Tworetzky says their increased success over the years isn’t the result of improved technology, but from a better understanding of the procedure itself. The team now functions like a well-oiled machine, which allows them to intervene even earlier in a pregnancy, and gives the underdeveloped chamber more time to develop properly before birth. They have also gotten better at identifying which patients are ideal fetal cardiac intervention candidates, which leads to better overall outcomes.

In Jack’s case, early identification and intervention meant everything. Ten years after his historic procedure, Jennifer and Henry are reminded of that every time their son snags a fly ball and sinks a basket.

“Jack really defines himself as an athlete, and given his original diagnosis, that’s pretty amazing,” Jennifer says. “Had we not addressed his heart condition before he was born he may have never been given that opportunity. Watching him come into his own as a player and teammate is a real reminder of just how lucky we are.”

For more information about fetal cardiology and resources for expectant parents, visit