Johns Hopkins experts discuss these two life-saving procedures and reviews the advantages and risks of each.
The pain of angina, usually experienced in the chest, is caused by a shortage of blood and oxygen to the heart muscle due to partial blockage of a coronary artery. The two goals in treating angina symptoms are to decrease the heart’s demand for oxygen and to increase its blood supply.
Several types of drugs can often help control angina pain. But when medication is not successful, revascularization—bypass surgery or angioplasty—may be necessary.
Since neither bypass surgery or angioplasty is a cure for atherosclerosis, it is essential to continue dietary and other preventive lifestyle measures and, in many cases, to take lipid-lowering drugs, blood pressure-lowering drugs, and aspirin after undergoing one of these procedures.
Angioplasty and Bypass Surgery -- Two Techniques to Improve Blood Flow
Each year more than 300,000 people in the United States undergo coronary artery bypass graft surgery (often called CABG or, simply, bypass surgery). During bypass surgery, a blood vessel from elsewhere in the body is used to reroute blood around a segment of a coronary artery narrowed by atherosclerosis. When needed, five or more bypass grafts can be performed during a single bypass surgery.
About 90%of people who undergo bypass surgery experience relief of angina symptoms after the procedure. Bypass surgery is extremely successful, even for people with extensive heart disease or who are elderly. But bypass surgery is arduous for patients, requiring general anesthesia and four to six days of hospitalization. And bypass surgery is usually performed with the help of a heart-lung machine that maintains blood circulation while the heart is stopped.
About 640,000 Americans a year undergo percutaneous transluminal coronary angioplasty (often called PTCA or, simply, angioplasty). Angioplasty involves inserting a balloon-tipped catheter into an artery; the balloon is guided to the diseased section of the coronary artery and inflated to break up and compress artery-clogging plaque.
Conventional angioplasty does not remove atherosclerotic plaque from the coronary arteries but instead widens the channel (lumen) through which blood flows by squeezing the plaque against the artery wall, cracking the hard part of the plaque, and/or stretching the artery.
About 90% of people notice an immediate improvement in symptoms when the artery lumen is at least 50% open after angioplasty. In about 85% of cases, a small, scaffold-like device called a stent is permanently placed in the artery during angioplasty to help keep the artery open. This helps reduce the rate of restenosis (further narrowing of the artery) to 10% to 20% (compared to 20% to 40% without a stent).
Angioplasty is performed in a cardiac catheterization laboratory and generally takes about one to two hours. Angioplasty does not require general anesthesia and usually involves no more than a night’s stay in the hospital. The risks associated with angioplasty are low.
Factors To Weigh in Choosing Angioplasty or Bypass Surgery
Angioplasty has several advantages over bypass surgery. Angioplasty is a relatively simple procedure, there is no need for general anesthesia, and the rigors of open heart surgery are avoided.
A major disadvantage of angioplasty is restenosis in the first six months after the procedure. People who undergo angioplasty must accept the risk that a repeat angioplasty or, ultimately, bypass surgery may become necessary.
Recurring angina is another consideration. These risks are considerably decreased with the implantation of a stent. Another disadvantage to angioplasty is that many people with coronary heart disease are not suitable candidates for angioplasty.
Bypass surgery may keep arteries open longer and improve blood flow through the coronary arteries more than angioplasty. Bypass surgery generally provides good relief of angina for at least five years.
In addition, bypass surgery is generally favored over angioplasty in people with one or more of the following:
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Disease in the left main coronary artery. This vessel is the main artery supplying blood to the heart, and even a brief period of blockage could damage heart muscle or be fatal.
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Diffuse coronary heart disease. Angioplasty is not effective for the treatment of multiple blockages in several vessels.
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Blockages at an arterial branch. If the blockage is at a point where one artery meets another, angioplasty may move the plaque into the adjacent artery, causing a new blockage.
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Diabetes. In the Bypass Angioplasty Revascularization Investigation (BARI) study, seven-year survival for people with diabetes was significantly better in those who underwent bypass surgery (76%) than angioplasty (56%). However, this study was conducted before traditional and drug-coated stents were available, and if the study were repeated today the results may be different.
Other factors. Other factors that make bypass surgery a better choice than angioplasty include severe disease of the three major coronary arteries (especially in people with reduced left ventricular function) and a history of heart failure.
Two drawbacks to bypass surgery are longer hospital stays and rehabilitation time than with angioplasty. In addition, a recent study of 261 bypass surgery patients found that about 40% of them had a decline in cognitive function that persisted five years after surgery. It is possible, however, that this decline was caused by underlying vascular disease in these patients and not the bypass surgery itself.
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