• Study compares success rates of coronary bypass procedures

    September 2009

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    Coronary artery bypass graft (CABG) surgery is one of the most common surgical procedures performed in the United States. According to the National Center for Health Statistics, 450,000 CABG surgeries were performed in 2006, with many people requiring more than one operation. The procedure involves replacing clogged vessels in the heart by harvesting an artery or vein from another part of the body, then grafting it to the blocked coronary artery, thereby bypassing the blocked portion of the coronary artery.

    In people who are candidates for CABG surgery, the results are usually excellent, with 85 percent of patients having significantly reduced symptoms, less risk for future heart attacks and a decreased chance of dying within 10 years following the surgery.

    In the past, vein grafting was done by open harvesting - making a long incision in the patient’s leg from ankle to groin. Unfortunately, this method often resulted in wound infections and pain for the patient. But in 1996 scientists developed a minimally invasive vein-removal technique using an endoscope. Patients have come to prefer endoscopic vein-graft harvesting over open harvesting because it reduces the risk of infections, lessens pain and shortens the length of hospitalization. It is now used in 70 percent of CABG surgeries. But there hasn't been much scientific data on the clinical outcomes.

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    How the study was conducted

    Researchers at Duke University recently conducted a secondary analysis of 3,000 patients who had undergone CABG. They looked at 1,753 patients who had endoscopic harvesting and 1,247 who had open harvesting. They found that endoscopic vein harvesting was associated with increased vein-graft failure and adverse clinical outcomes. Their findings were published in the July 16, 2009, issue of the New England Journal of Medicine.

    They used a database from the PREVENT IV trial, a multicenter trial conducted to test a new drug that was developed to prevent vein failure following CABG. Vein-graft failure can cause grafted arteries to become blocked, requiring additional surgeries. The drug tested in the PREVENT IV trial, edifoligide, proved to have no effect on preventing vein-graft failure.

    “A year to 18 months after the surgery, patients who received endoscopically harvested veins had a 47 percent rate of vein-graft failure, while those in the open harvesting group showed a 38 percent failure rate.” 

    For purposes of their study, the Duke researchers defined vein-graft failure as blockage of at least 75 percent of the graft. Clinical outcomes they looked for included death, myocardial infarction and repeat revascularization. A year to 18 months after the surgery, patients who received endoscopically harvested veins had a 47 percent rate of vein-graft failure, while those in the open harvesting group showed a 38 percent failure rate. At three years, the endoscopic group also had higher rates of death, myocardial infarction or repeat revascularization (20.2 percent in the endoscopic group vs. 17.4 percent in the open harvesting group).

    Study limitations

    The authors note that their study was not randomized and did not take into consideration the level of experience of the practitioners who harvested the veins. At the time of the PREVENT IV trial, from which the current data was taken, there were two different endoscopic devices for harvesting the vein. The different techniques employed by each could have played a rol in their findings, the Duke researchers note.

    They do not recommend that doctors return to open-vein harvesting. Instead, they state that further investigation and randomized clinical trials evaluating the effect of endoscopic harvesting should be conducted.

    Until further data is available, they state, the increased risk of worse outcomes with endoscopic harvesting should be weighed against its known short-term benefits.

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Page last updated: 8/7/2015 1:42:02 PM
  • What the news means for you

    Endoscopic procedure still best alternative

    Chand Ramaiah, MD, PhD
    Cardiothoracic surgery

    Wright, Heather, MDOpen harvesting, if done properly by an experienced practitioner, gives very good quality veins. The downside of that is the long incision in the leg, resulting in an enormous amount of complications. Ten to 20 percent of the patients will have complications after this procedure. They may also have long-term chronic pain. I have seen personally patients losing a leg as a result of open-vein harvesting. So at UK, we have stopped using this method.

    With the endoscope, you can harvest the leg vein with a 1-inch incision and perhaps a couple of 5-millimeter stab incisions. But like any advanced procedure, it takes experience. There are several devices in use today. We use the Vaso-View, which is one of the most widely used and is now in its seventh generation. It took me 20 to 30 cases to really get comfortable with the device. In the hands of a less experienced person, the vein can be destroyed.

    Limitations of the Duke study

    The Duke study is based on early data, when these devices were first coming out. I have done more than 1,000 endoscopic procedures.

    The data used by the researchers comes from the PREVENT IV trial, which was not designed to look for problems with the method of vein harvesting. Its purpose was to look at the drug E2FD to see if it prevented vein stenosis when a person has coronary artery bypass surgery. At the time of this trial, the majority of people who do vein harvesting were being trained.

    “The data used by the researchers comes from the PREVENT IV trial, which was not designed to look for problems with the method of vein harvesting.” 

    The actual vein harvesting is usually done by physician’s assistants (PAs), who do excellent work once they are trained. Patients coming to UK for surgery almost always request the endoscopic procedure. However, there are circumstances which make this a poor option for some. For example, if the vein is very superficial and the skin very thin, we would have to do open harvesting.

    Coronary artery bypass surgery

    The majority of patients who undergo surgery for bypassing blocked arteries are those who have had a heart attack, kidney failure or diabetes. Most have multiple blockages. Many have previously had stents inserted in arteries, but stents generally do not provide as long-lasting results as surgery, especially in diabetic and renal failure patients.

    However, because of the popularity of stents in recent years, bypass surgery numbers have actually gone down significantly across the nation. The reason bypass surgery is recommended over stents is that it provides long-lasting results, albeit at the expense of invasiveness. Stents can be inserted through a catheter that goes up through the groin to the artery, without an incision. Patients can usually go home the next day.

    The cardiologist will consider whether a particular patient is better served with surgery rather than stents. We make sure they need the surgery and are not too sick. Our goal is to achieve long-lasting results for the patient and, if surgery is necessary, make it as painless as possible.  

    Dr. Ramaiah is director of both minimally invasive cardiac surgery and the UK Heart Transplant Program, as well as associate professor of surgery in the UK College of Medicine.

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