Bypass Surgery Vs Coronary Stents Biology Essay

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This paper compares two common procedures to eliminate coronary artery disease or treatment for heart attacks. The two procedures compared are the bypass surgery and the implanting of coronary stents. This paper states how both procedures are carried out and some benefits of each. Also, this paper provides studies that have been done that compare the two procedures. It was hypothesized that bypass surgeries are preferred to correct heart disease or treat a heart attacks. However, after reviewing many studies, it can be found that bypass surgeries are more preferred when there are a greater number of blocks in the heart and coronary stents are used more when there are fewer blocks. Also, many times, stents are used in combination with a bypass surgery.

Keywords: bypass surgery, stent, artery

During one year, more than one million Americans will experience a heart attack causing severe permanent damage to the heart muscle. In order for the heart to function correctly, oxygen must be supplied to the heart by blood through the coronary arteries. If the arteries have plaque buildup, the blood cannot flow through correctly and therefore the oxygen supply to the heart is inadequate. If the plaque hardens, it will then crack and coagulation will begin. Platelets will come to the injured area and form a clot, if the clot blocks off the artery, the blood will not be able to flow through to the heart and the heart will not receive the necessary oxygen. When the heart is depleted of oxygen, severe damage to the muscle occurs which is called a heart attack (WebMD, 2010). There are a few different ways to prevent a heart attack, or improve the condition of the heart shortly after a heart attack has occurred. The most common treatments of a heart attack are to place stents in the narrowed arteries or to have a coronary bypass surgery. It is hypothesized that coronary bypass surgery is a better treatment for a heart attack.

Stents may be placed in narrowed arteries in order to reopen the artery and allow blood to flow correctly through the artery. Stents are small mesh tubes that are made of metal. They provide frame work for the artery to keep them from closing up. In order for the stent to be put into place, a guide wire that contains a balloon catheter will be placed into the artery. Then the balloon tip is inflated and the stent enlarges to hold the artery open. The balloon is then deflated and taken out but the stent will remain in the artery. The artery will then heal around the stent. In recent medicine, some stents contain medicines that will reduce restenosis or re-narrowing of the artery (Berger, 2009).

A very common surgery done in the United States is a bypass surgery. A bypass surgery is essentially making a new path for blood to flow to the heart. During a bypass, the heart must be fully exposed. Most people are connected to a heart lung bypass machine since the heart is stopped. This machine allows the blood to stream throughout the rest of the body during the surgery. A blood vessel is taken from one part of the body and attached to the heart near the area of the blockage (WebMD, 2010).

About one third of patients with coronary artery disease will have stents placed in their arteries. Many people prefer this procedure rather than the bypass because it is less invasive. The entire procedure can last from one to two hours and be done with local anesthesia or with mild sedation (Michaels, 2002). Stents should be placed in arteries within ninety minutes of arriving at the hospital and no later than twelve hours after a heart attack has occurred (Berger, 2009). Most of the patients will be able to leave the hospital the next morning after the procedure and get back to regular activities within one week. After the procedure, the patients will need to take aspirin and a blood thinner in to prevent a clot from forming on the stent (Michaels, 2002).

Almost ten percent of patients with coronary artery disease will have a bypass surgery to correct the problem (Michaels, 2002). This procedure is better for patients that have two or three coronary arteries that are narrowed. This surgery will require general anesthesia. The patient will then need to remain in the hospital for four to seven days for observation. This procedure may take up to three months to fully recover.

Although both procedures are used quite frequently, a choice must be made when the arteries are blocked. A bypass is more preferred by physicians when diabetes, heart failure, or numerous narrowed arteries are present. Some physicians prefer to do a bypass surgery because with stenting, restenosis is likely to occur. Recently, stents that are coated with medication that will prevent the unwanted growth in the artery have drastically reduced restenosis. New development for a bypass surgery is a minimally invasive direct coronary artery bypass. This procedure is much less invasive; small incisions between the ribs are made to operate on the artery rather than cutting through the sternum to reveal the entire heart. Also, the heart is not stopped during this procedure. However, if there is more than one artery that needs bypassed, this minimally invasive procedure may not be an option (Michaels, 2002).

In October of 2003 through December of 2004, a study was done that compared coronary artery bypass surgery and coronary stenting. In this study, patients that had mulit-vessel coronary artery disease and received the stents containing drugs to prevent re-narrowing or who had a bypass surgery were compared on death, heart attack, or the patient needing another artery procedure (Hannan, 2008).

The results of the study showed that with the bypass surgery there was a lower rate of death and heart attack than the stents containing medicine with patients having a multi-vessel disease. For patients with the two-vessel disease, there was no significant difference in the death rates noted. Also noted in the study were three subgroups at high risk. These groups were patients with diabetes, patients eighty years or older, and patients having left ventricular ejection below forty percent. There were no drastic differences in the death rate between the bypass and the stents but for the left ventricular ejection group and the eighty or older group had lower death rates with the bypass.

Research, in accordance with the above study, shows that stents are as effective as a bypass surgery, but the benefit of the stents are shorter than the bypass surgery. After a patient has received stents, it is very common for the need of further interventions. Some research has shown that the location of the blockage will change the effectiveness of the particular procedure. For example, if a blockage occurs in the left main coronary artery, the bypass surgery may improve survival rate rather than stents.

A study published in the New England Journal of Medicine in 2008 from Korea shows comparison of patients with the left main coronary artery blocked and the outcome of having stents or the bypass surgery. In this study, there were 1100 patients receiving stents and 1100 patients receiving the bypass surgery. All of the patients had been studied on basis of having a heart attack after the procedure or needing further interventions to fix the artery again, and death. Going along with other previous studies, again there was no drastic difference in death rates or of heart attacks of the different groups. However, again, the patients who had the stents placed in their arteries were about five times as likely to need further intervention and to re-open the blocked artery again (Wascher, 2009).

When trying to alleviate coronary artery disease, it is obvious that bypass surgeries and stents are both acceptable means of allowing the blood to flow through the heart. In both procedures, the heart gets what it needs most, oxygen, in a more adequate manner. However, As hypothesized, a bypass surgery is a better treatment for heart attacks. This way, there is no need for further interventions a couple of years after the procedure. When using stents, studies stated that almost all patients had re-narrowed arteries.