Catheterization Offers Less Invasive Treatments, pg. 2

But Lasala still isn''t satisfied. That''s why he''s been at the forefront of the most recent innovation in catheter-based CAD treatment: drug-coated stents. Lacing the mesh cylinders with low doses of drugs designed to slowly diffuse into the artery appears to further decrease the risk of restenosis. Lasala''s team was one of the key participants in research that led to the FDA''s landmark approval of a Johnson & Johnson stent in April 2003, the first federally approved drug-coated stent.

"It is absolutely astounding how much progress we''ve made in such a short period of time," Lasala says. "Our early results with drug-coated stents are almost too good to be true — restenosis rates have dropped to less than 5 percent, and we expect them to be even lower as we continue to smooth out the wrinkles. This may be the most important advancement in interventional cardiology this decade.

Tiny heart attack
Along with such impressive results in treating conditions like CAD, catheter-based interventions have gone beyond clogged arteries to treat other serious heart conditions.

One of the newer procedures, developed in the early 1990s by a European scientist named Ulrich Sigwart, relies on an unlikely ally: a heart attack.

Richard G. Bach, MD, associate professor of medicine and director of the cardiac intensive care unit at Barnes- Jewish Hospital, helped to introduce the procedure, called septal ablation, in the St. Louis region. Then a faculty member at Saint Louis University, Bach was part of a team that was among the first centers in the United States to use septal ablation in the treatment of patients with hypertrophic obstructive cardiomyopathy (HOCM).

Patients with HOCM have abnormally thick heart muscles, particularly between the two lower chambers of the heart. The thickened muscle makes it more difficult for the heart to pump blood to the rest of the body, and its enlarged size obstructs the passageway through which blood normally flows. HOCM often affects very young individuals and is the leading cause of sudden death in athletes.

Previously, the only option for treating HOCM patients who didn''t improve with drug therapy was to surgically remove a portion of the enlarged heart muscle.

Using septal ablation, cardiologists inject 200-proof alcohol through a catheter into the branch of the artery that feeds the section of muscle obstructing blood flow. The alcohol causes a localized heart attack, killing an area of tissue about the size of a grape.

Bach found it hard to imagine that this less invasive approach would help a patient so severely afflicted by HOCM that he could barely get out of bed. But it did.

"The result was beyond what I ever expected," Bach recalls. "Our patient''s condition was so extreme that I didn''t know if we could help him. But we did the procedure and the next day he was up and walking, feeling dramatically better. I''ve now seen that remarkable outcome re-iterated over and over again in many other patients."

Though septal ablation doesn''t actually cure the underlying condition, it does substantially relieve symptoms more than 90 percent of the time. For this reason, Bach''s team proceeds with cautious optimism and is investigating the long-term benefits of the procedure, as well as studying ways to improve the technique.

In collaboration with Bruce D. Lindsay, MD, associate professor of medicine, Bach recently performed the first septal ablation for HOCM using a magnetically guided catheter. Instead of a wire, catheters used in the Magnetic Navigation System contain a magnetic tip, which is directed by a computer-controlled magnetic chamber positioned around the patient. The system, which was developed by St. Louis-based Stereotaxis, Inc., in collaboration with School of Medicine researchers, enables cardiologists to maneuver the catheter around particularly sharp twists in the arteries that are difficult to navigate with a traditional, wire-threaded catheter.

On the horizon
Washington University cardiologists also have been selected to test three catheter-based approaches to fixing leaky valves in the heart and are evaluating a catheter alternative to surgical treatment of a common birth defect called patent foramen ovale (PFO), a type of hole in the heart that is one of the main causes of strokes in people under age 55.

"For the foreseeable future, there will always be complex cases in which open-heart surgery is the best option for patients with heart or blood vessel diseases," Bach says. "But what''s truly exciting — and the reason I went into interventional cardiology — is that angioplasty allowed us to begin radically altering someone''s condition without surgery. Now we''re extending that to a wider range of diseases, like HOCM and treatment of valvular disease and PFOs. It just keeps getting better."