Balloon angioplasty is an invasive surgical procedure to relieve a condition called atherosclerosis in which the arteries become clogged by deposits of fatty material called plaque, severely restricting blood circulation to the heart, brain, or extremities. In severe cases, the end result is heart attack, stroke, or the amputation of a limb due to gangrene. By inserting a balloon-tipped catheter into a blocked artery and inflating the balloon, plaque is compressed against the inner vessel walls allowing blood to pass freely.
In 1929, German physician Werner Forssmann (1904-1979) devised a way to thread a catheter--a long, thin, flexible tube--through a vein from an arm into the heart. In 1958, Mason Sones invented a way to visualize individual coronary arteries, a technique called selective coronary arteriography. In 1964 Charles T. Dotter and Melvin Judkins of the University of Oregon combined these advances to successfully perform transluminal (along the lumen, or cavity, of a blood vessel) angioplasty (blood vessel repair) using a fluoroscope to guide a catheter to the artery and dilate the blocked area. At the University Hospital in Zurich, Switzerland, Andreas Gruentzig began investigating ways of adapting transluminal angioplasty to clear blockage in the relatively small coronary arteries by adding a tiny inflatable balloon to the tip of the catheter. On September l6, 1977, he performed the first coronary balloon angioplasty on a human patient, a thirty-six-year-old insurance salesman, avoiding the need for coronary bypass surgery.
With refinements in technique and technology, Percutaneous Transluminal Coronary Angioplasty (PTCA), a procedure in which the catheter is inserted via the arteries and the aorta into a coronary artery, rapidly came into widespread use around the world as a relatively simple, inexpensive, and safe alternative to open-heart surgery for coronary bypass, dramatically improving the quality of life for many patients suffering from angina (heart pain). However, results are temporary due to restenosis, or renarrowing of the arteries, which occurs in 20- 50% of cases, often within weeks or months of the procedure. Stents are often inserted to hold the vessel open.
A technique pioneered by several groups of researchers in the early 1980s uses lasers, introduced by catheter, to vaporize plaque in arteries followed by balloon angioplasty. Laser angioplasty is currently approved for use in leg arteries only, as it carries a significant risk of perforating the blood vessels being treated. Ultrasound devices are often used to remove plaque, and device called a "Rotoblator"--an extremely thin catheter wire tipped with a miniature diamond-coated drill which revolves at 190,000 rpm--is used in severe cases. Phase II clinical trials scheduled to begin in 1998 will test the AngioRad(TM) Gamma System, a procedure designed to reduce the risk restenosis. During this procedure--the first to focus on in-stent restenosis--a tiny radioactive wire is inserted into the artery or stent, which appears to inhibit growth of smooth muscle cells, lowering the incidence of restenosis.
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