by Gila Reckess, Washington University Medical Public Affairs

A physician skillfully threads a thin catheter over a wire and through an artery, inching toward the heart of a patient whose health hinges on the procedure''s outcome. Following the catheter''s tip via an X-ray monitor, the cardiologist wields tiny tools to forestall life-threatening coronary disease. The journey, from a small puncture site in the thigh through the body''s inner recesses to the vital heart, has taken modern cardiology 50 years to envision, refine and put to effective use.

Roots of intervention
In 1929, a German surgical trainee named Werner Forssmann inserted a catheter into a vein in his arm and guided it into the right side of his heart. He then walked to the X-ray room and became the first person to prove, using imaging, that catheters could be used to study the living, human heart. His intrepid experiment got him fired; later, in 1956, it earned him a Nobel Prize.

By that time, the use of catheters was revolutionizing the state of cardiac diagnosis by measuring the amount of oxygen in the blood and locating clogged arteries. Two decades later, Dr. Andreas Grunzig went a step further, using balloon catheters to treat heart patients. With that, the non-surgical treatment of heart conditions — interventional cardiology — was born.

Cardiac cath can: Expand and clear passages, insert a tube to hold an artery open, place long-acting drugs for continued treatment, attack a little tissue to rescue the heart, plug a hole in the heart.

Opening the way
The rapid evolution of interventional cardiology over the past 30 years can be traced by the progression of treatment for coronary artery disease (CAD), a condition in which the heart''s main blood vessels become narrowed or clogged by the buildup of plaque. According to the American Heart Association, more than 13 million Americans have CAD, and it remains the leading cause of death in this country.

Before the use of catheters, patients whose conditions did not improve with drugs typically underwent surgery in which the diseased artery is bypassed by a blood vessel from the leg, arm or chest. The operation not only harvests a blood vessel from another part of the patient''s body, it also necessitates making a 12- to 18-inch incision in the chest — both of which result in scarring and postoperative pain.

The most dangerous aspects of bypass surgery, however, are the use of general anesthetic and a heart-lung bypass machine to divert blood away from the heart during the operation, temporarily stopping the heart from beating.

The catheter-based alternative, percutaneous transluminal coronary angioplasty (PTCA), avoids those issues. Interventional cardiologists typically insert the catheter into a blood vessel in the groin and watch X-ray images as they maneuver it through the artery''s natural twists and turns. When it reaches the clogged portion of a coronary artery, a balloon on the tip of the catheter is inflated, compressing plaque buildup against the blood vessel''s wall and reopening the passage to blood flow.

The advent of this less invasive approach has revolutionized both the treatment and prognosis of CAD. More than 1 million PTCAs will be performed in the United States in 2004, surpassing the number of bypass operations by more than 50 percent.

And while the essence of balloon angioplasty, as PTCA is also called, is the same as when it debuted in 1977, what has changed are the balloon''s accessories —and, as a result, the procedure''s effectiveness.

Keeping it open
In 1989, John M. Lasala, MD, medical director of the School of Medicine''s cardiac catheterization laboratory, witnessed a seminal moment in the history of heart care.

Then a cardiology fellow at Yale University, Lasala observed as his mentor Henry Cabin, MD, used a small metal cylinder to prop open a patient''s clogged artery — one of the first times the device, called a stent, was used in the United States.

"There was silence in the room," recalls Lasala, who also is director of interventional cardiology at Barnes-Jewish Hospital. "Henry said, ''You''re looking at the future.'' It literally sent a shiver up my spine."

His mentor was right.

While balloon angioplasty generally succeeds in opening arteries, about 30 to 50 percent of blood vessels become reclogged, or restenosed, within months of the procedure. Furthermore, balloon results were acutely unstable, requiring urgent bypass surgery in 3 to 7 percent of cases. As Lasala witnessed first-hand in 1989, the addition of stents — short narrow metal tubes often in the form of mesh- — significantly alleviates both problems. These small cylinders fit around the balloon and expand as it inflates. The stent then remains in place after the balloon and catheter are removed, serving as scaffolding and holding plaque buildup at bay.

Since the Food and Drug Administration (FDA) approved the first stents in 1994, the number of patients whose arteries become reclogged is about half the rate of traditional balloon angioplasty. The Washington University cardiology team at Barnes-Jewish Hospital has one of the lowest restenosis rates in the country, with an average of just 16 percent of all patients returning for further treatment.

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