March 24, 2000

Rare procedure used to open newborn’s blocked heart valve

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Dr. Thomas Doyle

Rare procedure used to open newborn's blocked heart valve

Membranous pulmonary atresia is a rare disorder. Vanderbilt treats a few cases each year.

The condition, a variation of pulmonary atresia, is detected in newborns with imperforated pulmonary valves, which block the flow of blood to the lungs.

There are a number of methods available for the treatment of this abnormality. The valve can be surgically opened. Alternatively, cardiologists have employed a number of techniques to open the valve in the cath lab including pushing a stiff wire across the valve or burning a hole with standard radio frequency equipment.

Now a new procedure using a not-yet approved device called the Nykanen Radio Frequency Perforation Catheter is being touted as a more effective, safer technique to remedy the condition. The device is designed to instantly heat up the designated tissue, cause the cells to burst and create a small hole.

Recently, Vanderbilt's Dr. Thomas P. Doyle, assistant professor of Pediatrics, requested emergency IRB and FDA approval to use the device. It was granted and Vanderbilt became the first hospital in the state to use it.

"I think it has the potential to become the safest, most effective way to treat this condition," says Doyle. "With other techniques, we would use a wire or catheter to open the valve. There is always the chance of puncturing the wall of the heart. It is very risky because of the potential for bleeding to death.

"Although this new technique is not without risks, the novelty of it is it functions specifically to create a small hole."

Doyle says the perforation device worked in less than a second. It works by inserting and guiding a catheter into the heart; the perforation catheter is then guided through it. Once positioned on the closed valve, energy is applied. The cells at the tip of the catheter burst leaving a small hole. (In previous treatments, it could take a few tries before a hole was made.) A wire is then passed through the hole to allow balloon dilution of the valve.

This procedure is not yet FDA-approved, but Doyle says Vanderbilt is moving forward with plans to be listed as one of the investigational sites.

"This particular device is different primarily because of the two safety features," Doyle says.

"One, it is exceedingly small. Should a puncture be made in the wrong place, the risk of a life-threatening injury is much smaller; two, the instantaneous effect of the device versus a continued try at making a hole is better.

"There are other advantages also. If this technique can be used, it should improve recovery time and diminish the cost of hospitalization as well."

Drs. Ann Kavanaugh-McHugh, assistant professor of pediatrics, and Mary Porisch, a senior pediatric fellow, assisted Doyle.