Coronary artery disease (CAD) is caused by “hardening” or “atherosclerosis” of the coronary arteries on the surface of the heart. The interior walls of arteries are normally smooth and flexible, allowing blood to flow easily. But, deposits of fat, or plaques that may build up inside the arterial wall would narrow down the artery and could reduce or even completely stop the blood flow.
Clinical syndromes of the disease, called Angina, include pain and discomfort in the chest, arms and lower jaw. The first suggestion for amelioration and resolution of these symptoms would be a change in one’s lifestyle including smoking cessation, a low fat/cholesterol diet, weight loss, regular exercise, stress management, diabetes control and blood pressure control, in addition to medications. In cases where medicine therapy fails one of the following procedures might be suggested:
This category of surgeries might be divided into two main subgroups: traditional open heart surgery called coronary artery bypass graft (CABG) and minimally invasive off-pump surgery. The former group includes a complete opening up of the chest with heart beat recessed. Therefore, a heart-lung machine artificially maintains circulation while the surgeon operates on the heart. In more recent techniques called “off-pump coronary artery bypass” or “beating heart”, CABG surgery is performed through relatively small incision in inter-rib spaces so that no cardiopulmonary bypass (heart-lung machine) is required. In bypass surgeries, the surgeon uses a portion of a healthy vessel (either an artery or vein) from the leg, chest, or arm to create a detour or bypass around the blocked portion of the coronary artery. About 10% of the patients require this category of surgery.
Angioplasty is the technique of mechanically widening narrowed or obstructed arteries. An empty and collapsed balloon on a guide wire, known as a balloon catheter, is passed into the narrowed locations and then inflated to a fixed size using water pressures. The balloon forces expansion of the inner white blood cell/clot plaque deposits and the surrounding muscular wall, opening up the blood vessel for improved flow, and the balloon is then deflated and withdrawn. A stent may or may not be inserted at the time of ballooning to ensure the vessel remains open. Unlike angioplasty and stents, which pushes the plaques into the vessel wall, atherectomy involves removing the plaque burden within the vessel and four types of devices might be used for this purpose: orbital, rotational, laser, and directional. Typically about one third of CAD patients undergo angioplasty.
Choosing between the two categories depends on surgeon diagnosis, patient preference, as well as physical characteristics of the patient including number and severity of blockage of arteries, medical history, etc.
Dr. Jones a medicine professor at Duke University believes that angioplasty’s main selling point is that it’s much less traumatic than a bypass and one can get back to his/her normal daily life within a few days. But it’s also less permanent. One recent review found that 89% of bypass patients were free of angina one year later, compared with 74% of patients who had an angioplasty. The convenience of angioplasty comes with a price. Up to one-quarter of people who have angioplasty must have it repeated, or have bypass surgery, within a few years. And anyone who gets a drug-eluting stent must take medicine for at least a year to prevent the formation of potentially deadly clots around the stent.
Summarizing the results of the studies up to year 2002 could indicate the relative preference of the two methods in the following situations.
This is while a review including 17,000 bypass surgeries and angioplasties performed in 2003 and 2004 indicated that the boundaries could not be set as clearly as the above classification. In this study the investigators compared deaths immediately after these procedures, deaths within 18 months, and heart attacks within 18 months. Bypass surgery was better, but not by much. An extra 1.6% to 2% of people in the bypass group were still alive and had not had a heart attack after 18 months. The biggest difference between the two procedures was in the need for repeat procedures. Among those who initially underwent angioplasty, 30% needed a second procedure within 18 months, compared with 5% in the bypass group. This study collected information from 2003 and 2004, when the use of drug-eluting stents was in full swing. So the results are relevant today. But the cardiologists and patients chose which procedure to have.
Hence, choosing between the two procedures is a complicated task but it could be expected that future comparative studies including more novel technologies like laser atherectomy would shed more light on the issue and facilitate patients’ decisions.
. A.D. Michaels, K. Chatterjee, “Angioplasty Versus Bypass Surgery for Coronary Artery Disease”, Circulation, vol. 106, pp. e187-e190, 2002.
. “Health.com, article Should You Opt for Bypass Surgery or an Angioplasty?”, Health Media Ventures, 2013.