The Delicate Art of Intervention
It’s a little after 8 am on a Thursday in September when a neonatal ICU nurse wheels two-day-old Ryder Uhlendorff into catheterization lab 8 in the Heart and Vascular Institute of Inova Fairfax Hospital. Asleep in an incubator and wrapped in a blanket, Ryder barely stirs as the nurse leans over him.
“Bye-bye, baby,” she says softly as she leaves the room.
Russell D’Sa, a cardiovascular invasive specialist and supervisor of the cath lab, lifts the infant onto a table covered with sterile cloth. The lab temperature is 60 degrees, and Ryder cries when he’s exposed to the cool air.
Dr. Robert Mesrobian, section chief of pediatric anesthesiology, leans over Ryder to administer the muscle relaxant propofol through an intravenous line. This allows Mesrobian to slide an endotracheal tube down Ryder’s throat and put him on the ventilator that takes over his breathing. Mesrobian also administers nitrous oxide and sevoflurane, putting Ryder into an anesthetic sleep. The digital monitors above Ryder read out his vital signs—heart rate 169, oxygen level 92 percent. His blood pressure fluctuates but remains in the normal range.
Although dark blue at birth, Ryder is pinker now and looks almost normal. Yet he’s so gravely ill that he would die in days, perhaps hours, without medicine or intervention. Because surgery is inherently risky, Dr. James Thompson, an interventional pediatric cardiologist, will try to correct Ryder’s heart problem with a catheter, but he knows this will be a challenging case.
D’Sa preps Ryder for the catheterization procedure. “You know what they say about interventional cardiology,” he says. “It’s only as good as the jerk on the end of the wire.”
The specific procedure is balloon pulmonary valvuloplasty, developed in the early 1980s at Johns Hopkins by pediatric cardiologist Jean Kan and her associates. Just 37 years old when she devised the procedure, Dr. Kan is now retired and living outside St. Louis. A modest woman who speaks with a soft voice, she seems almost embarrassed to accept credit for her pioneering work when I telephone her to talk.
She says her contribution stood on the shoulders of many, especially the ground-breaking research of Dr. Andreas Grüntzig, a German physician who in the 1970s developed the balloon-catheter technique, commonly called angioplasty, for opening blocked coronary arteries.
Kan says they first needed a larger balloon because the pulmonary artery is bigger than a coronary artery. They then tested the procedure on animals and found that it didn’t set off a fatal cardiac arrhythmia or cause a vessel rupture, their two major concerns. With additional research and permission from the Johns Hopkins investigational committee, Kan and her colleagues performed the first human valvuloplasty in 1981 on Sharon Owens, a young Maryland girl with pulmonic stenosis. The procedure worked perfectly, and her stenosis was cured.
“We followed Sharon for several years, and she never needed to be recatheterized,” Kan says.
The impact of Kan’s research is evident in a recent Pub Med literature search that turned up nearly 3,400 articles on balloon valvuloplasty.
The manufacturer named the device the Owens Pulmonary Valvuloplasty Balloon because Kan didn’t want it named for herself. “I never considered myself a medical pioneer,” says Kan, now in her mid-sixties, “I was part of a continuum.”
While ballooning technology became the first major application of interventional cardiology, over the past 20 years the field has revolutionized the treatment of heart disease in children and adults. Besides pulmonic stenosis, catheter techniques today routinely repair septal defects (the single most common congenital heart anomaly), install vascular stents, open constricted aortas, and are in the beginning stages of replacing malfunctioning heart valves. They’re also used in “hybrid” procedures in ORs in conjunction with surgery to correct certain complex heart defects, and at Children’s Hospital Boston catheter techniques have successfully repaired certain congenital heart defects in utero.
Standing six feet, five inches, well conditioned from running every morning, wearing clogs and a lead apron so heavy that it gives him back trouble from time to time, Dr. Thompson leans in to get a closer look at the monitor displaying fluoroscopic x-ray pictures of Ryder’s beating heart, made clearer with contrast dyes. He shakes his head.
“That’s a very sick-looking right ventricle,” he says. “This is why this case could not be put off for another day.”
In the lead-protected control room just outside the cath room, Thompson points out what he’s talking about.
“See the right ventricle right there?” he says. “See the blood in there, this dark area? It just pools inside the ventricle. It’s not getting pumped out because the pulmonary valve won’t open.”
The first sign that Ryder might have a congenital heart problem appeared in May when his mother, Rebecca, a special-education teacher in the Frederick County public-school system, underwent a routine prenatal ultrasound exam that revealed a single umbilical artery where there are normally two. Though the condition isn’t alarming in itself, Rebecca and her husband, Ryan, learned from the doctors that a single umbilical artery caries a 20-percent risk of a birth abnormality and a 5-percent chance of a cardiac abnormality.
Congenital heart defects are the most common birth defects, affecting 1 in every 125 live births, and even in this era of modern technology they remain the deadliest birth anomaly.
The first ultrasound exam of Ryder’s heart, then about the size of a grape, suggested that he had a relatively mild pulmonic stenosis, or narrowing of the pulmonary artery. This is the same congenital heart defect I was born with in 1939. The pulmonary artery transports unoxygenated blood from the right ventricle to the lungs. If the stenosis is severe enough, the right heart eventually fails from overwork, and death quickly follows.
Although the first glimpse of Ryder’s heart in May suggested a mild defect, pediatric cardiologist James Telep wanted to take a second look when Ryder’s heart was more developed. On July 26, when Ryder’s gestational age was about six months, Dr. Telep studied the ultrasound pictures and observed something not apparent earlier: There was no discernible blood flow through the pulmonary artery. It virtually stopped at the pulmonary valve. Telep knew that the unborn baby had a severe case of pulmonic stenosis.
He told Rebecca that the pulmonary valve had an opening the size of a pinhole, meaning that plans for her baby’s birth had to be changed. He recommended that she have Ryder at Inova Fairfax Hospital because the baby would need immediate medical attention for his heart condition and there was no better place.
Rebecca left Telep’s office trembling. She walked to her car, put her head against the steering wheel, and cried. Ryder wasn’t only her first child but also her parents’ first grandchild.
From her car, Rebecca phoned her mother in upstate New York. In a halting voice, she told her how scared she felt; her mother promised to drive down with Rebecca’s grandmother. Rebecca tried to reach her husband, an electrician, at work, but he didn’t answer his cell phone. At home, Rebecca went onto the Internet to learn more about Ryder’s condition.
“I finally had to stop reading about it,” she says, “because I was scaring myself.”
One thing would prevent Ryder from being stillborn. In a developing fetus, a vessel called a ductus arteriosis forms a connection between the pulmonary artery and the aortic arch. This permits unoxygenated blood to bypass the fetus’s fluid-filled lungs and go directly into the aorta to be pumped out to the mother’s placenta to acquire oxygen. The ductus arteriosis normally closes after birth, but researchers found that a naturally occurring hormone called prostaglandin would keep the ductus open when administered to newborns. Prostaglandin was one of the most significant discoveries in pediatric heart care and has saved the lives of countless newborns such as Ryder with congenital heart defects.
“A Light Went Off”
Shortly after birth, doctors give Ryder prostaglandin to allow blood to get to the lungs to be oxygenated. Two days later, Thompson studies the bank of monitors above Ryder’s cath table.
During medical school at the University of North Carolina, Thompson attended a lecture on interventional pediatric cardiology, after which the speaker invited anyone in attendance to cut pathology class to observe the cath-lab clinic. Thompson was the only one to take him up on the offer.
“A light went off that day,” he says, “and I knew I wanted to do interventional cardiology.”
On the monitors, Thompson sees evidence of the damage inflicted on Ryder’s heart during his fetal development. It happened because Ryder’s right ventricle labored with every beat to force blood into his lungs through a pulmonary valve that didn’t open. The fierce resistance causes the ventricle to work ever harder and its walls to thicken, much as any muscle thickens with repeated exertion. With this thickening, called cardiac hypertrophy, the amount of blood the right ventricle can hold is compromised and its ability to beat normally is hindered.
“See how stiff his right ventricle has become?” Thompson says, pointing on the monitor to the ventricle’s sluggish, shallow beats.
On the day I was born in February 1939, in what is now Yale–New Haven Hospital in Connecticut, a young doctor who listened to my chest and heard my heart murmur—a grade five on a scale of one to six—told my mother, “I’m afraid he won’t live beyond adolescence.”
His opinion, cruel as it was to my mother’s ears, reflected the fact that at the time the heart remained off limits to surgical intervention, eliminating any hope of fixing the defect.
I grew up often feeling sorry for myself because I loved sports but wasn’t allowed to play on any of my high-school teams once a doctor listened to my chest.
Now, gazing at the images of Ryder’s tiny heart and seeing how severe his stenosis is and how badly damaged his right ventricle, I understand as I never have before that my pulmonic stenosis could have been much more severe, and if it had been, I might not have lived beyond a few days, much less through adolescence.
Thompson has told Ryder’s parents he’s concerned about sliding a balloon catheter through the pinhole in Ryder’s pulmonary valve to open it up. As he studies the beating of Ryder’s heart on the monitor, his concern deepens. If he can’t open the pulmonary valve with a catheter, Ryder will need surgery.
The room darkens except for the bright lights beaming down on Ryder. X-ray fluoroscopy doesn’t show the heart or other soft tissue very well, but it shows the wire D’Sa has inserted as well as the catheter, so it is necessary. Thompson uses it sparingly to reduce Ryder’s radiation exposure. MRIs don’t emit radiation, but that technology isn’t yet up to this task. Besides radiation exposure, other major risks for Ryder are cardiac arrest, arrhythmia, bleeding, and stroke from a blood clot; in procedures such as this, the unexpected lurks.
On an overhead monitor, a 4 French catheter, the thinnest available for this procedure—and with the even thinner guide wire inside it—can be seen snaking its way up Ryder’s femoral vein on its way to his vena cava, the body’s largest vein, and into the right atrium. From here Thompson, with D’Sa assisting, maneuvers the catheter, which carries a deflated balloon, down through the tricuspid valve and into the right ventricle.
“I hope this pulmonary valve works normally after ballooning,” Thompson says, “but I don’t know.”
The room grows quiet as Thompson tries to position the catheter in the pulmonary valve, a challenge given the small size of Ryder’s heart and the pinhole opening in the valve. If Thompson can work the tip of the wire with a diameter of 14 one-thousandths of an inch through the hole, he’ll be able to position the catheter in the valve and expand the balloon.
When he thinks he has it where he wants it, Thompson inflates the saline-filled balloon.
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