From the NICU to the Swimming Pool: Preemie Heart Surgery Patient Making a Big Splash

By Evan Koch

Alex’s journey has taken her from a heart procedure in the NICU to the swimming pool.

Alexandra “Alex” Merhan’s trip to the pool in mid-August was a milestone event for many reasons.

After more than a year of swim lessons, the 3-year-old was skilled and confident enough to join her instructor in the water for the first time without either of her parents by her side.

But the occasion was extra special for Pamela and Matthew Merhan, benchmarking just how much progress their daughter has made since she was born more than two months premature with a congenital heart defect at Children’s Memorial Hermann Hospital at Memorial Hermann-Texas Medical Center.

“I look at the pictures of Alex when she was born and it’s crazy to think how far she has come,” Pamela Merhan said. “I wasn’t sure she’d be able to do things like swim lessons and now she’s running all around.”

Complications emerge following a premature birth

Alex weighed only 2 pounds, 7 ounces at birth and was immediately placed in the Level IV neonatal intensive care unit (NICU) at Children’s Memorial Hermann Hospital for round-the-clock care.

Soon after she was born, it was discovered that a vessel in Alex’s heart was not closing as it should and would require medical intervention.

Typically, the vessel, called the ductus arteriosus, remains open during fetal development to allow blood to bypass the non-functioning lungs. For most newborns, the vessel closes within days of birth. When it doesn’t properly close, the open vessel is called a patent ductus arteriosus (PDA).

PDA is a relatively common and problematic congenital heart defect among extremely premature babies because of the stress it places on the heart and lungs, which can lead to permanent damage and complications with other organs. The resulting fatigue can also severely inhibit growth and development, something the Merhans witnessed firsthand with their daughter.

“Alex was a fighter and spunky, but the PDA left her too tired to take a bottle and affected her ability to function,” Pamela Merhan said.

Advanced technology creates another option for PDA repair

Alex weighed less than 3 pounds when she was born more than two months premature, and with a congenital heart defect.

While some infants and newborns are able to treat PDA with medicine, in cases where that isn’t an option or when medicine has proved unsuccessful, the remaining alternatives are minimally invasive cardiac catheterization repair and open heart surgery.

Cardiac catheterization procedures have been used for decades to successfully manage PDA, but were not available to extremely premature babies, like Alex, until recently. That’s because the devices used in such procedures, which navigate the veins or arteries to reach and repair the heart defect, were too large and considered unsafe for babies as small as Alex.

“Catheterization was previously reserved for children who were older, home from the hospital and oftentimes weighed more than 12 pounds,” said John Breinholt, M.D., co-director of Children’s Heart Center at Children’s Memorial Hermann Hospital and chief of pediatric cardiology. “For the smallest, premature patients whose PDA was much more significant, their only option was surgery.”

Open heart surgery, while effective, requires a much longer recovery than catheterization. It was a prospect the Merhans did not want to face.

Luckily, they didn’t have to.

By the time Alex was born, Children’s Heart Center  had already begun using new, advanced technology to perform a catheterization procedure called transcatheter device closure for PDA repair on extremely premature babies.

The tiny preemie would not need open heart surgery.

“In the past few years, we have performed PDA closure exclusively in the catheterization lab for these tiny babies in a way that is minimally invasive,” said Dr. Breinholt, who is also the director of the Division of Pediatric Cardiology in the department of Pediatrics at McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth). “The benefit to doing this procedure earlier is that we get the children out of the NICU sooner and back to growing and developing.”

A quick procedure jumpstarts Alex’s growth

When Alex had grown to nearly 5 pounds at two-and-a-half months of age, she became one of the first extremely premature babies at Children’s Heart Center to have the PDA repaired through a transcatheter device closure.

“I was a worried mom, so I did a lot of research,” Pamela Merhan said. “But Dr. Breinholt made us feel as calm as we could.”

Alex was put under general anesthesia for the procedure. Dr. Breinholt then passed a catheter roughly the diameter of a coffee stirrer through a vein in Alex’s leg, and used advanced imaging to navigate the path to her heart, where a small device was placed to close the PDA.

The procedure took approximately 20 minutes.

“The recovery from a transcatheter device closure is quick and there is little more than a small bandage placed over the catheter entry point in the leg,” Dr. Breinholt said.

The Merhans’ “little peanut” responded immediately.

“Alex was able to take an entire bottle for the first time 30 hours after the procedure,” Pamela Merhan said. “We were able to go home two weeks later.”

More than 100 transcatheter device closures for PDA have been successfully performed at Children’s Heart Center since Alex’s procedure, including at least half on children who weigh less than 6 pounds.

Alex is thriving at home with her parents and big brother, Lucas.

Meeting milestones

The Merhans were grateful for their time at the hospital and the staff and providers who took care of Alex. But they knew their daughter would face challenges in catching up developmentally once she was discharged. Pamela Merhan admits the first year was a tough one for the family.

But Alex continued to battle outside of the hospital. Less than three years after leaving the NICU, Alex was thriving. Her parents enrolled her in soccer and music lessons—and swimming.

“Now that she’s older and we’re seeing her meet all these milestones, we are so thankful that Alex is going to be great,” Pamela Merhan said. “We are so grateful for her.”

“My daughter would not be alive today if not for this amazing medical technology.”

Click here to contact Children’s Heart Center at Children’s Memorial Hermann Hospital and learn more about the other patient stories and specialty services available.


  1. So happy for the whole family esxtended to grandma. I know how hard they have been working on Alex progress. It paid off❤️????

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