A little over three decades ago, a Swiss surgeon fashioned a balloon-tipped catheter in his own kitchen, then used it to perform the first successful coronary angioplasty on a human. The concept was not entirely new; catheters had been used for medical purposes by the Egyptians as early as 3000 B.C. Yet in 1976 when Dr. Andreas Gruentzig presented results of his studies using angioplasty on dogs, there were skeptics in his audience at the American Heart Association annual meeting.

A year later, a similar AHA audience burst into applause when Dr. Gruentzig presented results of his first four cases using angioplasty to open the blocked coronary arteries of human patients.

Balloon angioplasty, known medically as percutaneous transluminal coronary angioplasty (PTCA), has been a breakthrough for relieving heart symptoms such as chest pain or shortness breath and is now primary treatment for a heart attack in progress. About 1.2 million Americans undergo it every year.

A physician inserts a catheter, or thin, flexible tube, into the femoral artery near the groin and, with the help of x-ray images on a monitor, guides it through blood vessels to the coronary artery that has become narrowed or blocked by plaque deposits.

Inside the catheter is an even thinner catheter with an inflatable balloon near its tip. When it reaches the proper place in the artery, the balloon is inflated repeatedly for several seconds, compressing the plaque and opening the artery. When performed on arteries that are less than 50 percent blocked, about 90 percent of patients notice an immediate improvement in symptoms such as chest pain and shortness of breath.

Minimally Invasive

Starting with Dr. Gruentzig’s first case, angioplasty is an outpatient procedure that can be performed in one to two hours in a cardiac catheterization laboratory. No general anesthesia is required, and the patient can usually return home the next day.

Angioplasty does not remove any plaque but rather works by squeezing the plaque against the arterial wall and stretching the artery, thereby improving blood flow.

When Dr. Gruentzig’s first patient was brought in for testing 10 years later, the artery treated with angioplasty had narrowed only slightly–less than 10 percent. It soon became apparent, however, that this kind of result could not be expected consistently.

In a small number of cases, the artery would collapse soon after the balloon was deflated, creating the need for emergency bypass graft surgery to correct the problem. More commonly, in about 30 percent of cases, the artery would begin to narrow again, a process known as restenosis, requiring a repeat procedure.

During the early- to mid-1980s, several new catheter-based devices were introduced–tiny blades that would slice away plaque or lasers that would vaporize it. None of these proved any more effective than traditional balloon angioplasty.

The biggest advance came in the early 1990s with the introduction of the stent, a mesh tube that could be inserted after the balloon had completed its job to provide a scaffolding to hold the artery open. The first stent was used in 1986, and the Palmaz-Schatz stent was approved for use in the United States in 1994.

Stents solved the problem of immediate artery closure, and they lowered the rate of restenosis...but unfortunately without eliminating it. The stent, in fact, revealed a new reason for restenosis: the growth of smooth muscle or scar tissue at the site of the stent, occurring typically after about six months in 25 percent of cases.

The next step was to try to stop this growth by coating stents with a substance known to inhibit the process of restenosis. Low doses of radiation have been tried but the current focus involves medication coated on a metal stent with a timed release.

The first two drug-eluting stents (DES) approved for use in the United States were the Cordis Cypher (sirolimus-eluting) and Boston Scientific’s Taxus (paclitaxel-eluting). More recently approved were the Medtronic Endeavor and the Xience/Promus stent. All of these were approved for certain patients–those with less extensive artery disease who are not at immediate risk of a heart attack and have no other complications such as diabetes or kidney disease.

Because drug-eluting stents proved so successful at reducing the rate of restenosis, they became widely used, sometimes for patients who did not meet the initial qualifications. This is a practice known as off-label use, and it may be partly responsible for a new problem that has surfaced–the potential for late-developing blood clots at the site. Blood clots are always a risk right after insertion of a stent, but with drug-eluting stents they may develop months or years later–a problem known as late thrombosis. While late thrombosis is not common, it can lead to a heart attack or sudden death.

An expert panel convened by the FDA in December, 2006 reviewed all the evidence and concluded that, when used as directed, drug-eluting stents are a safe, beneficial choice that do not increase the risk of death. Patients, however, should take two anti-clotting medications, aspirin indefinitely and Plavix for at least one year.

Advances in stent design continue; one now being tested is made to be absorbed and disappear after it has done its work. But even with all of the advances that have come since 1977, it is important to remember that angioplasty, while an effective way to open a partially blocked artery, is not a cure for atherosclerosis.

The best treatment for arteries, whether healthy or diseased, includes exercise, a healthy diet, not smoking and control of blood pressure, blood sugar and cholesterol. Some individuals with mild heart disease can manage their condition effectively, at least for a time, with medication while those with severe or multiple blockages may need bypass surgery.

Kerri T. Musselman, PharmD