Balloon angioplasty is performed over a quarter of a million times each year in the United States. It ranks as one of the most common surgical procedures in the country.
As an effective treatment of the atherosclerosis, or artery blockage, that results from coronary heart disease, it has an initial success rate higher than 90%. The operation itself is much less invasive and traumatic for the patient than coronary artery bypass surgery, with patients often leaving the hospital in 24 hours and able to perform even heavy activities in less than a month. As a result, balloon angioplasty is the preferred surgical procedure for correcting coronary artery disease, which is the single greatest cause of death in the United States.
Balloon angioplasty is currently one of three standard treatments for the disease, the other two being bypass surgery (Innovation #5) and medication. Whereas coronary artery bypass surgery involves re-routing the blood through venous grafts attached to the blocked arteries, balloon angioplasty actually clears the way through the blocked arteries themselves. This is accomplished by inserting a thin tube, known as a catheter, with an uninflated balloon at one end, into an artery. The balloon is threaded all the way up through this artery, typically the femoral artery, to the site of the blockage, most often in one of the coronary arteries. When the balloon reaches the blockage, the surgeon inflates the balloon at the end of the catheter. The swelling balloon flattens the plaque against the wall of the artery, which enables the blood to flow past the blockage. In many cases, the balloon is replaced with a "stent," a wire mesh tube which holds the artery open after the operation. An animated illustration of this procedure can be found at the following url: http://www.mdmercy.com/vascular/discoveries/balloon_stent.html
According to Dr. Christian T. Campos, Associate Professor of Surgery at the University of Massachusetts Memorial Hospital in Boston, "Every time we do an angioplasty, there’s a certain number of patients who come back with restenosis. When there’s a blockage in the left main artery, we tend not to do angioplasty because if it narrows back down the patient can die suddenly. But if you do one vessel, the chance of a patient coming back is pretty low." Because of the possibility of restenosis, angioplasty is most common among coronary artery disease patients with blockages in only one or two arteries. But new technology may allow physicians to use the relatively non-invasive procedure of angioplasty in more and more cases.
The first successful balloon angioplasty was performed in 1977 in San Francisco during a heart bypass surgery. But the first step towards the procedure may have occurred in 1929, when Dr. Forsmann pioneered catheterization by inserting a catheter in his own heart, from a vein in his left arm. Catheterization gave rise to the procedure of coronary angioplasty, and throughout the ‘40s, ‘50s, and ‘60s, both procedures improved and matured. In 1964, Dr. Charles Dotter first attempted to open limb arteries by means of a balloon-tipped catheter. Over the next decade, this procedure evolved, and the first angioplasty was performed thirteen years later. Since the mid-1980s, the success of the procedure has climbed more than 10%, and the technology continues to improve.
Many of angioplasty’s benefits have come as a result of the role it can play in combination with other procedures. While the procedure is used as a stand-alone in a minority of heart operations, it plays a vital role in a wide variety of potentially lifesaving operations. For many patients, the best solution to coronary heart disease is some combination of excimer laser angioplasty, directional atherectomy, stent angioplasty, and more conventional balloon angioplasty.
Balloon angioplasty is also an exciting procedure because of a number of new developments on the technological horizon. In March of this year, a study presented at a meeting of the American College of Cardiology demonstrated that stents coated with the drug rapamycin could reduce the chances of scar tissue’s forming around the stent. Currently, one out of five patients suffer from blockages caused by scar tissue. But, in this recent study, not one patient suffered from blockages.
In January of this year, Dr. James Joye presented a new technique known as cryoplasty at the 14th annual International Symposium on Endovascular Therapy. Cryoplasty is much like traditional angioplasty; but during cryoplasty, the balloon at the tip of the catheter is inflated with nitrous oxide, also known as laughing gas. The gas cools to -10 degrees Celsius, a temperature which freezes the plaque and induces cell death. The body itself then disposes of the dead cells. In the initial study, there was zero incidence of blockages due to scarring around the stent, a result which would be remarkable if it could be duplicated on a larger scale. Dr. Joye has since begun a clinical trial to test this new technique in the coronary arteries of approximately 100 patients. (More information on this development can be found at http://www.cnn.com/2002/HEALTH/01/21/cryoplasty/index.html.)
And, less than a month ago, on November 20, a new study technique which incorporates the use of a filter in traditional angioplasty was presented to the American Heart Association (AHA). One of the risks of angioplasty has been that, in some cases, the procedure can dislodge particles from the arterial wall, which can then be carried to the brain and cause stroke. But this new technology, known as the AngioGuard, might minimize or eliminate this risk.
The AngioGuard has been compared to an umbrella: the device is threaded from the thigh artery to the carotid artery, where it opens into a basket that can catch particles dislodged from the arterial wall. The doctors then inflate a balloon to open the clogged artery, and insert a stent, exactly as in conventional angioplasty. After the patient has been examined by a neurologist, the filter is collapsed and removed by the surgical team. So far, the procedure has cut the risks of stroke and other complications in half. The physician who led the study, Dr. Jay S. Yadav of the Cleveland Clinic, has suggested that the filter could make angioplasty the first choice of approximately 200,000 Americans who undergo carotid artery surgery every year. (More information on these findings can be found on the American Heart Association’s webpage at http://216.185.112.5/presenter.jhtml;jsessionid=PAFYOSSPPHKX5WFZOAGSCZQ?identifier=11981)
