Curve Ball

Published on June 22nd, 2011 by Christina Echegaray.

Written by Christina Echegaray

Photo by John Russell

For five weeks, Ashleigh Hammer lay tethered to machines and bound in a web of wires and intravenous lines. On a day in early September, she gazed up at the blinking heart monitor beside her hospital bed.

Faster, faster, faster the monitor flashed. 120 beats – 200 beats – 250 beats – back to 200. Her heart was racing out of control.

“Mama, it’s happening again,” the 15-year-old anxiously advised her mother.


For the second time in 10 minutes, Ashleigh’s heart was racing so fast it was not able to pump blood. She went into cardiac arrest, a sign her failing, diseased heart couldn’t hold on much longer.

James Johns, M.D., professor of Pediatric Cardiology, who was walking by her room, revived her. But she needed a heart transplant. She was on the waiting list for a donor.

“It’s hard to come in and see your child laying there hooked up to a machine. But you know you’ve got to go through this to get to the next step,” said Patty Hammer, Ashleigh’s mom.

The waiting game had begun for a donor heart to be found.

Nearly 30 years ago, young patients, such as Ashleigh, wouldn’t have survived. The first pediatric heart transplants were not performed until the mid-to-late 1980s, when a new anti-rejection medication, cyclosporine, became available and improved patients’ chances of survival.

Vanderbilt Children’s Hospital, as it was known then, was an early innovator in pediatric cardiology and performed
Tennessee’s first heart transplant on a child in 1987, joining only a handful of centers that offered the surgery. Since the first transplant, the Monroe Carell Jr. Children’s Hospital at Vanderbilt has done more than 155 heart transplants in children, and remains the only pediatric heart transplant center in Tennessee.

Debra Dodd, M.D., visits with 1-year-old heart transplant patient Witt Deane. Photo by Susan Urmy.

“We initially did transplants for infants who had no other options,” said Debra Dodd, M.D., medical director of the
Pediatric Heart Transplant Program and associate professor of Pediatrics. “Since we started early, we are a getting a lot of follow-up from long-term patients, and what we have learned from them, we are able to apply those benefits to our patients today.”

About 300 pediatric heart transplants are performed worldwide each year. Children’s Hospital averages about 12-15 heart transplants annually to replace diseased hearts caused by congenital heart defects and acquired heart disease. Children’s Hospital stands among a select few centers that are considered to be high volume, and studies show that outcomes for adult and child transplant patients are best in high-volume programs.

Dodd, who has been with the transplant program since the beginning, has personally developed the program with help from a team of cardiologists and nurses, focusing on quality of care and success of outcomes. Children’s Hospital’s heart transplant patients have first-year survival rates of 94 percent compared to the national average of 89 percent, putting the heart program among the most successful in the nation.

Physicians in the Pediatric Heart Institute at Children’s Hospital follow as many as 120 pediatric heart transplant patients at any time. They offer what other centers don’t: steroid-free medications, fewer invasive procedures, and ultimately, a better quality of life.

“Each transplant throws something new at us that we have to work out,” said Dodd. “We see children who are very ill, slowing dying from heart disease. Two months out from a heart transplant, they are running around, and you can’t tell they are different from any other child.”

When Ashleigh was born in Morristown, on Tennessee’s northeast border, she appeared to be like any other infant, cooing and gazing at objects in the new world around her. But at 2 months old, Ashleigh stopped breastfeeding. Thinking she might be sick, Patty and Walter Hammer took her to the doctor.

She was diagnosed with cardiomyopathy, an acquired form of heart disease in which the heart muscle is too weak to perform properly. The cause of many cases is unknown, though it can be acquired after a viral infection.

Doctors told the Hammers that the muscle couldn’t be repaired, and the only option, when the heart is at end-stage function, is a heart transplant.

“Her doctor said she could stay the same until she was an old lady, or she could get worse,” Patty said.
Even with a weak heart muscle, Ashleigh became a rising softball star. Athletically, she outdid most peers with healthy hearts – until she was 11 and her heart started to weaken.

Her doctors sent her to Vanderbilt, more than four hours away, for the comprehensive care she needed, and that only Children’s Hospital could provide. An implantable cardioverter defibrillator (ICD) was placed in her heart to control the pace. Her softball career ended.

“You could never tell by looking at her that there was anything wrong,” Patty said.

Then at the end of the school year in May 2010, she couldn’t breathe going up a flight of stairs.  Another echocardiogram revealed her heart was not pumping blood properly.

Dodd admitted Ashleigh to the Pediatric Cardiology Intensive Care Unit in August to wait for a donor heart. To get on the national donor registry, cardiac physicians and surgeons evaluate the child for overall health and strength for surgery and eliminate any possible alternatives. Several factors determine the right match – blood type, weight, severity of illness, the use of mechanical support devices and distance  between the donor and receiving hospitals. The average wait for a donor heart is about six to eight weeks.

“We live in an advantageous spot in Tennessee,” said Bret Mettler, M.D., assistant professor of Pediatrics and surgical director of the Pediatric Heart Transplant Program. “We are centrally located, and we can go almost coast to coast to retrieve an organ.”

Previously, some children who needed a transplant might have died waiting, but more are surviving with the help of a Ventricular Assist Device (VAD).

Children’s Hospital employs the newest forms of mechanical support for pediatric patients. The devices mechanically pump blood for the heart throughout the body.

The VADs for children and infants are similar to those used in adults, though smaller versions.

Older children and adolescents, such as Ashleigh, have VADs more like the adult version. But for the smallest infants, doctors at Children’s Hospital received special permission to use the Berlin Heart, a small VAD designed for infants and small children – not yet approved by the U.S. Food and Drug Administration. In May 2010, Children’s Hospital successfully implanted Tennessee’s first Berlin Heart in 11-month-old Nathan Roberts, who thrived on the device until a heart was available seven months later. A happy, healthy Nathan, almost 2 years old, is now home in Alabama with his parents and two older sisters.

Doctors also utilize another device as a bridge to transplant, an extracorporeal membrane oxygenation (ECMO) machine. Patients can only be on ECMO for about three weeks, and must be sedated and on a ventilator.
On the VAD and the Berlin Heart machines, patients can be awake and active, allowing their bodies to regain strength in preparation for transplant.

“They may not be a suitable transplant candidate – yet,” said Mettler. “We look at how we can assist them to transplantation, through acute hospitalizations, to give their other organs a chance to recover and grow stronger.”
Ashleigh was Children’s Hospital’s first pediatric patient to use two ventricular assist devices (biVAD), one for each side of her heart. For about a week, two pumping mechanisms sat outside her body funneling blood in and out of her chest through a plastic tube.

“I woke up, and it was like a fish out of water batting on on my stomach,” Ashleigh joked.

On Sept. 21, two teams of surgeons – one to do the transplant and one to retrieve the donor heart – transplanted
Ashleigh’s new heart.

Now more than six months out from her transplant, she comes to Children’s Hospital once a month for checkups. With her healthy heart, she hopes to return to her second-base position on the softball field.

“I feel great. I’ve never felt this good,” Ashleigh said.

Ashleigh Hammer performs a stress exam to test her transplanted heart. Photo by John Russell.

The goal now for Ashleigh and other heart transplant patients is to have a quality of life for the long term, said Scott Baldwin, M.D., chief of the Division of Pediatric Cardiology and the Katrina Overall McDonald Chair in Pediatrics.

“Dr. Dodd has developed a quality program that allows children with heart transplants to live an essentially normal life,” said Baldwin.

Unlike many other transplant centers, Children’s Hospital uses a steroid-free immunosuppressant regimen, allowing the child’s body and heart to grow normally. Also, transplant patients used to have 14 biopsies in the first year to check the heart muscle, but Dodd’s team has limited the number of biopsies to two or three.

Most children can participate in regular activities, attend school and practice some competitive sports. Few are re-admitted to the hospital outside the immediate post-operative period.

“I don’t think there is any reason that someone from Tennessee would ever feel the need to leave the state to get the best care,” said Baldwin. “Our goal is to make sure people from all over the Southeast and the country will want to come here.”