Coronary artery bypass surgery - AbsoluteAstronomy.com

Coronary artery bypass surgery, also coronary artery bypass graft (CABG pronounced cabbage
Cabbage
Cabbage is a popular cultivar of the species Brassica oleracea Linne of the Family Brassicaceae and is a leafy green vegetable...

) surgery, and colloquially heart bypass or bypass surgery is a surgical procedure

Surgery

Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...

performed to relieve angina and reduce the risk of death from coronary artery disease

Coronary heart disease

Coronary artery disease is the end result of the accumulation of atheromatous plaques within the walls of the coronary arteries that supply the myocardium with oxygen and nutrients. It is sometimes also called coronary heart disease...

. Arteries

Artery

Arteries are blood vessels that carry blood away from the heart. This blood is normally oxygenated, exceptions made for the pulmonary and umbilical arteries....

or vein

Vein

In the circulatory system, veins are blood vessels that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart...

s from elsewhere in the patient's body are grafted

Medical grafting

Grafting refers to a surgical procedure to move tissue from one site to another on the body, or from another person, without bringing its own blood supply with it. Instead, a new blood supply grows in after it is placed. A similar technique where tissue is transferred with the blood supply intact...

to the coronary arteries to bypass atherosclerotic

Atherosclerosis

Atherosclerosis is a condition in which an artery wall thickens as a result of the accumulation of fatty materials such as cholesterol...

narrowings

Stenosis

A stenosis is an abnormal narrowing in a blood vessel or other tubular organ or structure.It is also sometimes called a stricture ....

and improve the blood

Blood

Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....

supply to the coronary circulation

Coronary circulation

Coronary circulation is the circulation of blood in the blood vessels of the heart muscle . The vessels that deliver oxygen-rich blood to the myocardium are known as coronary arteries...

supplying the myocardium (heart muscle). This surgery is usually performed with the heart stopped, necessitating the usage of cardiopulmonary bypass; techniques are available to perform CABG on a beating heart, so-called "off-pump" surgery.

History

The first coronary artery bypass surgery was performed in the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

on May 2, 1960, at the Albert Einstein College of Medicine

Albert Einstein College of Medicine

Albert Einstein College of Medicine is a graduate school of Yeshiva University. It is a not-for-profit, private, nonsectarian medical school located on the Jack and Pearl Resnick Campus in the Morris Park neighborhood of the borough of the Bronx of New York City...

-Bronx Municipal Hospital Center

Jacobi Medical Center

Jacobi Medical Center is a municipal hospital, under the direction of New York City Health and Hospitals Corporation, in Morris Park, Bronx, New York located at 1400 Pelham Parkway South; it is the largest Public Hospital in the Bronx with 470+ beds....

by a team led by Dr. Robert Goetz and the thoracic surgeon, Dr. Michael Rohman with the assistance of Dr. Jordan Haller and Dr. Ronald Dee. In this technique the vessels are held together with circumferential ligatures over an inserted metal ring. The internal mammary artery was used as the donor vessel and was anastomosed to the right coronary artery. The actual anastomosis with the Rosenbach ring took fifteen seconds and did not require cardiopulmonary bypass. The disadvantage of using the internal mammary artery was that, at autopsy nine months later, the anastomosis was open, but an atheromatous plaque had occluded the origin of the internal mammary that was used for the bypass.

Russian cardiac surgeon

Cardiac surgeon

A cardiac surgeon is a surgeon who performs cardiac surgery—operative procedures on the heart and great vessels.-Training:A cardiac surgery residency typically comprises anywhere from six to nine years of training to become a fully qualified surgeon...

, Dr. Vasilii Kolesov, performed arguably the first successful internal mammary artery–coronary artery anastomosis in 1964.

However, Goetz's has been cited by others, including Kolesov, as the first successful human coronary artery bypass. Goetz's case has frequently been overlooked. Confusion has persisted for over 40 years and seems to be due to the absence of a full report and to misunderstanding about the type of anastomosis that was created. The anastomosis was intima-to-intima, with the vessels held together with circumferential ligatures over a specially designed metal ring. Kolesov did the first successful coronary bypass using a standard suture technique in 1964, and over the next five years he performed 33 sutured and mechanically stapled anastomoses in St. Petersburg, Russia.

Dr. René Favaloro

René Favaloro

Dr. René Gerónimo Favaloro was an Argentine cardiac surgeon who created the technique for coronary bypass surgery....

, an Argentine surgeon, achieved a physiologic approach in the surgical management of coronary artery disease—the bypass grafting procedure—at the Cleveland Clinic in May 1967. His new technique used a saphenous vein

Great saphenous vein

The great saphenous vein , also long saphenous vein, is the large superficial vein of the leg and thigh.The terms "safaina" and "el safin" have both been claimed as the origin for the word "saphenous."-Path:The GSV originates from where the dorsal vein of the first digit...

autograft to replace a stenotic segment of the right coronary artery

Right coronary artery

The right coronary artery originates above the right cusp of the aortic valve. It travels down the right atrioventricular groove, towards the crux of the heart.At the origin of the RCA is the conus artery....

. Later, he successfully used the saphenous vein

Saphenous vein

Saphenous vein may refer to:*Great saphenous vein*Small saphenous vein...

as a bypassing channel, which has become the typical bypass graft technique we know today; in the U.S., this vessel is typically harvested endoscopically, using a technique known as endoscopic vessel harvesting

Endoscopic vessel harvesting

Endoscopic vessel harvesting is a surgical technique that may be used in conjunction with coronary artery bypass surgery . For patients with coronary artery disease, a physician may recommend a bypass to reroute blood around blocked arteries to restore and improve blood flow and oxygen to the heart...

(EVH). Soon Dr. Dudley Johnson extended the bypass to include left coronary arterial systems. In 1968, Doctors Charles Bailey, Teruo Hirose and George Green used the internal mammary artery instead of the saphenous vein for the grafting.

Terminology

There are many variations on terminology, in which one or more of "artery", "bypass" or "graft" is left out. The most frequently used acronym for this type of surgery is CABG , pluralized as CABGs . More recently the term aortocoronary bypass (ACB) has come into popular use. CAGS (Coronary Artery Graft Surgery, pronounced phonetically) should not be confused with coronary angiography (CAG).

Arteriosclerosis

Arteriosclerosis

Arteriosclerosis refers to a stiffening of arteries.Arteriosclerosis is a general term describing any hardening of medium or large arteries It should not be confused with "arteriolosclerosis" or "atherosclerosis".Also known by the name "myoconditis" which is...

is a common arterial disorder characterized by thickening, loss of elasticity, and calcification of arterial walls, resulting in a decreased blood supply.

Atherosclerosis

Atherosclerosis

Atherosclerosis is a condition in which an artery wall thickens as a result of the accumulation of fatty materials such as cholesterol...

is a common arterial disorder characterized by yellowish plaques of cholesterol

Cholesterol

Cholesterol is a complex isoprenoid. Specifically, it is a waxy steroid of fat that is produced in the liver or intestines. It is used to produce hormones and cell membranes and is transported in the blood plasma of all mammals. It is an essential structural component of mammalian cell membranes...

, lipids, and cellular debris in the inner layer of the walls of large and medium-sized arteries.

Number of bypasses

The terms single bypass, double bypass, triple bypass, quadruple bypass and quintuple bypass refer to the number of coronary arteries bypassed in the procedure. In other words, a double bypass means two coronary arteries are bypassed (e.g. the left anterior descending (LAD) coronary artery and right coronary artery (RCA)

Right coronary artery

); a triple bypass means three vessels are bypassed (e.g. LAD, RCA, left circumflex artery (LCX)

Left circumflex artery

The "LCX", or left circumflex artery is an artery of the heart.-Course:...

); a quadruple bypass means four vessels are bypassed (e.g. LAD, RCA, LCX, first diagonal artery of the LAD) while quintuple means five. Bypass of more than four coronary arteries is uncommon.

A greater number of bypasses does not imply a person is "more sick", nor does a lesser number imply a person is "healthier." A person with a large amount of coronary artery disease (CAD) may receive fewer bypass grafts owing to the lack of suitable "target" vessels. A coronary artery may be unsuitable for bypass grafting if it is small (< 1 mm or < 1.5 mm depending on surgeon preference), heavily calcified (meaning the artery does not have a section free of CAD) or intramyocardial (the coronary artery is located within the heart muscle rather than on the surface of the heart). Similarly, a person with a single stenosis

Stenosis

A stenosis is an abnormal narrowing in a blood vessel or other tubular organ or structure.It is also sometimes called a stricture ....

("narrowing") of the left main

Left coronary artery

The left coronary artery, abbreviated LCA and also known as the left main coronary artery , arises from the aorta above the left cusp of the aortic valve.-Branching:...

coronary artery requires only two bypasses (to the LAD and the LCX). However, a left main lesion places a person at the highest risk for death from a cardiac cause.

The surgeon reviews the coronary angiogram prior to surgery and identifies the lesions (or "blockages") in the coronary arteries. The surgeon will estimate the number of bypass grafts prior to surgery, but the final decision is made in the operating room upon examination of the heart.

Indications for CABG

Several alternative treatments for coronary artery disease exist. They include:

Medical management (anti-anginal medications plus statins, antihypertensive
Antihypertensive
The antihypertensives are a class of drugs that are used to treat hypertension . Evidence suggests that reduction of the blood pressure by 5 mmHg can decrease the risk of stroke by 34%, of ischaemic heart disease by 21%, and reduce the likelihood of dementia, heart failure, and mortality from...

s, smoking cessation
Smoking cessation
Smoking cessation is the process of discontinuing the practice of inhaling a smoked substance. This article focuses exclusively on cessation of tobacco smoking; however, the methods described may apply to cessation of smoking other substances that can be difficult to stop using due to the...

, tight blood sugar
Blood sugar
The blood sugar concentration or blood glucose level is the amount of glucose present in the blood of a human or animal. Normally in mammals, the body maintains the blood glucose level at a reference range between about 3.6 and 5.8 mM , or 64.8 and 104.4 mg/dL...

control in diabetics
Diabetes mellitus
Diabetes mellitus, often simply referred to as diabetes, is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced...

)
Percutaneous coronary intervention
Percutaneous coronary intervention
Percutaneous coronary intervention , commonly known as coronary angioplasty or simply angioplasty, is one therapeutic procedure used to treat the stenotic coronary arteries of the heart found in coronary heart disease. These stenotic segments are due to the build up of cholesterol-laden plaques...

(PCI)

Both PCI and CABG are more effective than medical management at relieving symptoms, (e.g. angina, dyspnea

Dyspnea

Dyspnea , shortness of breath , or air hunger, is the subjective symptom of breathlessness.It is a normal symptom of heavy exertion but becomes pathological if it occurs in unexpected situations...

, fatigue). CABG is superior to PCI for some patients with multivessel CAD

The Surgery or Stent (SoS) trial was a randomized controlled trial that compared CABG to PCI with bare-metal stent

Coronary stent

A coronary stent is a tube placed in the coronary arteries that supply the heart, to keep the arteries open in the treatment of coronary heart disease. It is used in a procedure called percutaneous coronary intervention...

s. The SoS trial demonstrated CABG is superior to PCI in multivessel coronary disease.

The SYNTAX trial was a randomized controlled trial of 1800 patients with multivessel coronary disease, comparing CABG versus PCI using drug-eluting stents (DES). The study found that rates of major adverse cardiac or cerebrovascular events at 12 months were significantly higher in the DES group (17.8% versus 12.4% for CABG; P=0.002). This was primarily driven by higher need for repeat revascularization

Revascularization

Revascularization is "a surgical procedure for the provision of a new, additional, or augmented blood supply to a body part or organ." The term derives from the prefix re-, in this case meaning "restoration" and vasculature, which refers to the circulatory structures of an organ.Revascularization...

procedures in the PCI group with no difference in repeat infarctions or survival. Higher rates of strokes were seen in the CABG group.

The FREEDOM (Future Revascularization Evaluation in Patients With Diabetes Mellitus—Optimal Management of Multivessel Disease) trial will compare CABG and DES in patients with diabetes

Diabetes mellitus

Diabetes mellitus, often simply referred to as diabetes, is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced...

. The registries of the nonrandomized patients screened for these trials may provide as much robust data regarding revascularization outcomes as the randomized analysis.

A study comparing the outcomes of all patients in New York

New York

New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...

state treated with CABG or percutaneous coronary intervention

Percutaneous coronary intervention

Percutaneous coronary intervention , commonly known as coronary angioplasty or simply angioplasty, is one therapeutic procedure used to treat the stenotic coronary arteries of the heart found in coronary heart disease. These stenotic segments are due to the build up of cholesterol-laden plaques...

(PCI) demonstrated CABG was superior to PCI with DES in multivessel (more than one diseased artery) coronary artery disease

Coronary heart disease

(CAD). Patients treated with CABG had lower rates of death and of death or myocardial infarction than treatment with a coronary stent

Coronary stent

. Patients undergoing CABG also had lower rates of repeat revascularization. The New York State registry included all patients undergoing revascularization for coronary artery disease, but was not a randomized trial, and so may have reflected other factors besides the method of coronary revascularization.

The 2004 ACC

American College of Cardiology

The American College of Cardiology is a nonprofit medical association established in 1949 to advocate for quality cardiovascular care through education, research promotion, development and application of standards and guidelines, and to influence health care policy...

/AHA

American Heart Association

The American Heart Association is a non-profit organization in the United States that fosters appropriate cardiac care in an effort to reduce disability and deaths caused by cardiovascular disease and stroke. It is headquartered in Dallas, Texas...

CABG guidelines state CABG is the preferred treatment for:

Disease of the left main coronary artery (LMCA).
Disease of all three coronary vessels (LAD, LCX and RCA
Right coronary artery
The right coronary artery originates above the right cusp of the aortic valve. It travels down the right atrioventricular groove, towards the crux of the heart.At the origin of the RCA is the conus artery....

).
Diffuse disease not amenable to treatment with a PCI.

The 2005 ACC/AHA guidelines further state:
CABG is the preferred treatment with other high-risk patients such as those with severe ventricular dysfunction (i.e. low ejection fraction

Ejection fraction

In cardiovascular physiology, ejection fraction is the fraction of Blood pumped out of the Right Ventricle of the heart to the Pulmonary Circulation and Left Ventricle of the heart to the Systemic Circulation with each Heart beat or Cardiac cycle...

), or diabetes mellitus

Diabetes mellitus

Prognosis

Prognosis following CABG depends on a variety of factors, and successful grafts typically last 8–15 years. In general, CABG improves the chances of survival of patients who are at high risk (generally triple or higher bypass), though statistically after about five years the difference in survival rate between those who have had surgery and those treated by drug therapy diminishes. Age at the time of CABG is critical to the prognosis, younger patients with no complicating diseases doing better, while older patients can usually be expected to suffer further blockage of the coronary arteries.

Controversy

The value of coronary artery bypass surgery in rescuing someone having a heart attack (by immediately alleviating an obstruction) is clearly defined in multiple studies, but studies have failed to find benefit for bypass surgery vs. medical therapy in stable angina patients. The artery bypass can temporarily alleviate chest pain, but does not increase longevity. The "vast majority of heart attacks do not originate with obstructions that narrow arteries".

Loss of mental function is a common complication of bypass surgery, and should influence procedure cost benefit considerations. One published study using MRI imaging just after coronary bypass surgery found significant brain damage in 51% of patients.

Several factors may contribute to immediate cognitive decline. The heart-lung blood circulation system and the surgery itself release a variety of debris, including bits of blood cells, tubing, and plaques. For example, when surgeons clamp and connect the aorta to tubing, resulting emboli block blood flow and cause mini strokes. Other heart surgery factors related to mental damage may be events of hypoxia, high or low body temperature, abnormal blood pressure, irregular heart rhythms, and fever after surgery.

A safer and more permanent and successful way to prevent heart attacks in patients at high risk is to exercise, give up smoking, take "drugs to get blood pressure under control and drive cholesterol levels down to prevent blood clotting". Longer term, behavioral and medication treatment may be the only way to avoid vascular related loss of mental function.

Procedure (simplified)

The patient is brought to the operating room and moved on to the operating table.
An anaesthetist places a variety of intravenous lines and injects a painkilling agent (usually fentanyl) followed within minutes by an induction agent (usually propofol
Propofol
Propofol is a short-acting, intravenously administered hypnotic agent. Its uses include the induction and maintenance of general anesthesia, sedation for mechanically ventilated adults, and procedural sedation. Propofol is also commonly used in veterinary medicine...

) to render the patient unconscious.
An endotracheal tube is inserted and secured by the anaesthetist or assistant (e.g. respiratory therapist or nurse anaesthetist) and mechanical ventilation
Mechanical ventilation
In medicine, mechanical ventilation is a method to mechanically assist or replace spontaneous breathing. This may involve a machine called a ventilator or the breathing may be assisted by a physician, respiratory therapist or other suitable person compressing a bag or set of bellows...

is started. General anaesthesia is maintained by a continuous very slow injection of Propofol
Propofol
Propofol is a short-acting, intravenously administered hypnotic agent. Its uses include the induction and maintenance of general anesthesia, sedation for mechanically ventilated adults, and procedural sedation. Propofol is also commonly used in veterinary medicine...

.
The chest is opened via a median sternotomy
Median sternotomy
Median sternotomy is a type of surgical procedure in which a vertical inline incision is made along the sternum, after which the sternum itself is divided, or "cracked"...

and the heart is examined by the surgeon.
The bypass grafts are harvested - frequent conduits are the internal thoracic arteries
Internal thoracic artery
In human anatomy, the internal thoracic artery , previously known as the internal mammary artery , is an artery that supplies the anterior chest wall and the breasts...

, radial arteries
Radial artery
In human anatomy, the radial artery is the main blood vessel, with oxygenated blood, of the lateral aspect of the forearm.-Course:The radial artery arises from the bifurcation of the brachial artery in the cubital fossa. It runs distally on the anterior part of the forearm...

and saphenous vein
Saphenous vein
Saphenous vein may refer to:*Great saphenous vein*Small saphenous vein...

s. When harvesting is done, the patient is given heparin
Heparin
Heparin , also known as unfractionated heparin, a highly sulfated glycosaminoglycan, is widely used as an injectable anticoagulant, and has the highest negative charge density of any known biological molecule...

to prevent the blood from clotting.
In the case of "off-pump" surgery, the surgeon places devices to stabilize the heart.
If the case is "on-pump", the surgeon sutures cannulae into the heart and instructs the perfusionist
Perfusionist
A perfusionist, also known as a clinical perfusionist or a cardiovascular perfusionist, is a specialized health professional who operates the heart-lung machine during cardiac surgery and other surgeries that require cardiopulmonary bypass....

to start cardiopulmonary bypass (CPB). Once CPB is established, the surgeon places the aortic cross-clamp
Aortic cross-clamp
An aortic cross-clamp is a surgical instrument used in cardiac surgery to clamp the aorta and separate the systemic circulation from the outflow of the heart....

across the aorta and instructs the perfusionist to deliver cardioplegia
Cardioplegia
Cardioplegia is intentional and temporary cessation of cardiac activity, primarily for cardiac surgery.- Overview :The word cardioplegia means cardio-the heart and plegia- paralysis. Technically this means arresting or stopping the heart so that surgical procedures can be done in a still and...

(a special Potassium-mixture, cooled) to stop the heart and slow its metabolism. Usually the patient's machine-circulated blood is cooled to around 84 °F (28.9 °C)
One end of each graft is sewn on to the coronary arteries beyond the blockages and the other end is attached to the aorta
Aorta
The aorta is the largest artery in the body, originating from the left ventricle of the heart and extending down to the abdomen, where it branches off into two smaller arteries...

.
The heart is restarted; or in "off-pump" surgery, the stabilizing devices are removed. In cases where the aorta is partially occluded by a C-shaped clamp, the heart is restarted and suturing of the grafts to the aorta is done in this partially occluded section of the aorta while the heart is beating.
Protamine
Protamine
Protamines are small, arginine-rich, nuclear proteins that replace histones late in the haploid phase of spermatogenesis and are believed essential for sperm head condensation and DNA stabilization. They may allow for denser packaging of DNA in spermatozoon than histones, but they must be...

is given to reverse the effects of heparin
Heparin
Heparin , also known as unfractionated heparin, a highly sulfated glycosaminoglycan, is widely used as an injectable anticoagulant, and has the highest negative charge density of any known biological molecule...

.
The sternum is wired together and the incisions are sutured closed.
The patient is moved to the intensive care unit
Intensive Care Unit
thumb|220px|ICU roomAn intensive-care unit , critical-care unit , intensive-therapy unit/intensive-treatment unit is a specialized department in a hospital that provides intensive-care medicine...

(ICU) to recover. After awakening and stabilizing in the ICU (approximately one day), the person is transferred to the cardiac surgery ward until ready to go home (approximately four days).

Minimally invasive CABG

Alternate methods of minimally invasive coronary artery bypass surgery

Minimally invasive cardiac surgery

WIKI EDITSMinimally Invasive Heart Surgery, also minimally invasive cardiac surgery/coronary artery bypass grafting or The McGinn Technique is heart surgery performed through several small incisions instead of the traditional open-heart surgery that requires a median sternotomy approach...

have been developed. Off-pump coronary artery bypass

Off-pump coronary artery bypass

Off-pump coronary artery bypass or "beating heart" surgery is a form of coronary artery bypass graft surgery performed without cardiopulmonary bypass as a treatment for coronary heart disease. During most bypass surgeries, the heart is stopped and a heart-lung machine takes over the work of the...

(OPCAB) is a technique of performing bypass surgery without the use of cardiopulmonary bypass (the heart-lung machine). Further refinements to OPCAB have resulted in minimally invasive direct coronary artery bypass surgery

Minimally invasive direct coronary artery bypass surgery

Minimally Invasive Direct Coronary Artery Bypass is a surgical treatment for coronary heart disease that is a less invasive method of coronary artery bypass surgery . MIDCAB gains surgical access to the heart with a smaller incision than other types of CABG...

(MIDCAB), a technique of performing bypass surgery through a 5 to 10 cm incision.

Conduits used for bypass

The choice of conduits is highly dependent upon the particular surgeon and institution. Typically, the left internal thoracic artery

Internal thoracic artery

In human anatomy, the internal thoracic artery , previously known as the internal mammary artery , is an artery that supplies the anterior chest wall and the breasts...

(LITA) (previously referred to as left internal mammary artery or LIMA) is grafted to the left anterior descending artery and a combination of other arteries and veins is used for other coronary arteries. The right internal thoracic artery (RITA), the great saphenous vein

Great saphenous vein

from the leg and the radial artery

Radial artery

In human anatomy, the radial artery is the main blood vessel, with oxygenated blood, of the lateral aspect of the forearm.-Course:The radial artery arises from the bifurcation of the brachial artery in the cubital fossa. It runs distally on the anterior part of the forearm...

from the forearm are frequently used; in the U.S., these vessels are usually harvested endoscopically, using a technique known as endoscopic vessel harvesting

Endoscopic vessel harvesting

(EVH). The right gastroepiploic artery from the stomach

Stomach

The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...

is infrequently used given the difficult mobilization from the abdomen

Abdomen

In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...

Graft patency

Grafts can become diseased and may occlude in the months to years after bypass surgery is performed. Patency is a term used to describe the chance that a graft remains open. A graft is considered patent if there is flow through the graft without any significant (>70% diameter) stenosis in the graft.

Graft patency is dependent on a number of factors, including the type of graft used (internal thoracic artery, radial artery, or great saphenous vein), the size or the coronary artery that the graft is anastomosed with, and, of course, the skill of the surgeon(s) performing the procedure. Arterial grafts (e.g. LITA, radial) are far more sensitive to rough handling than the saphenous veins and may go into spasm if handled improperly.

Generally the best patency rates are achieved with the in-situ left internal thoracic artery (the proximal end is left connected to the subclavian artery

Subclavian artery

In human anatomy, the subclavian arteries are two major arteries of the upper thorax , below the clavicle . They receive blood from the top of the aorta...

) with the distal end being anastomosed with the coronary artery (typically the left anterior descending artery or a diagonal branch artery). Lesser patency rates can be expected with radial artery grafts and "free" internal thoracic artery grafts (where the proximal end of the thoracic artery is excised from its origin from the subclavian artery and re-anastomosed with the ascending aorta). Saphenous vein grafts have worse patency rates, but are more available, as the patients can have multiple segments of the saphenous vein used to bypass different arteries.

Veins that are used either have their valve

Valve

A valve is a device that regulates, directs or controls the flow of a fluid by opening, closing, or partially obstructing various passageways. Valves are technically pipe fittings, but are usually discussed as a separate category...

s removed or are turned around so that the valves in them do not occlude blood flow in the graft. LITA grafts are longer-lasting than vein grafts, both because the artery is more robust than a vein and because, being already connected to the arterial tree, the LITA need only be grafted at one end. The LITA is usually grafted to the left anterior descending coronary artery (LAD) because of its superior long-term patency when compared to saphenous vein grafts.

Sternal precautions

Patients undergoing coronary artery bypass surgery will have to avoid certain things for eight to 12 weeks to reduce the risk of opening the incision. These are called sternal precautions. First, patients need to avoid using their arms excessively, such as pushing themselves out of a chair or reaching back before sitting down. To avoid this, patients are encouraged to build up momentum by rocking several times in their chair before standing up. Second, patients should avoid lifting anything in excess of 5–10 pounds. A gallon (U.S.) of milk weighs approximately 8.5 pounds, and is a good reference point for weight limitations. Finally, patients should avoid overhead activities with their hands, such as reaching for sweaters from the top shelf of a closet or reaching for plates or cups from the cupboard.

Complications

People undergoing coronary artery bypass are at risk for the same complications as any surgery, plus some risks more common with or unique to CABG.

CABG associated

Postperfusion syndrome
Postperfusion syndrome
Postperfusion syndrome, also known as "pumphead" is a constellation of neurocognitive impairments attributed to cardiopulmonary bypass during cardiac surgery. Symptoms of postperfusion syndrome are subtle and include defects associated with attention, concentration, short term memory, fine motor...

(pumphead), a transient neurocognitive impairment associated with cardiopulmonary bypass. Some research shows the incidence is initially decreased by off-pump coronary artery bypass
Off-pump coronary artery bypass
Off-pump coronary artery bypass or "beating heart" surgery is a form of coronary artery bypass graft surgery performed without cardiopulmonary bypass as a treatment for coronary heart disease. During most bypass surgeries, the heart is stopped and a heart-lung machine takes over the work of the...

, but with no difference beyond three months after surgery. A neurocognitive decline over time has been demonstrated in people with coronary artery disease regardless of treatment (OPCAB, conventional CABG or medical management). However, a 2009 research study suggests that longer term (over 5 years) cognitive decline is not caused by CABG but is rather a consequence of vascular disease.
Nonunion
Nonunion
Nonunion is permanent failure of healing following a broken bone.Nonunion is a serious complication of a fracture and may occur when the fracture moves too much, has a poor blood supply or gets infected. Patients who smoke have a higher incidence of nonunion. The normal process of bone healing is...

of the sternum; internal thoracic artery
Internal thoracic artery
In human anatomy, the internal thoracic artery , previously known as the internal mammary artery , is an artery that supplies the anterior chest wall and the breasts...

harvesting devascularizes the sternum increasing risk.
Myocardial infarction
Myocardial infarction
Myocardial infarction or acute myocardial infarction , commonly known as a heart attack, results from the interruption of blood supply to a part of the heart, causing heart cells to die...

due to embolism, hypoperfusion, or graft failure.
Late graft stenosis
Stenosis
A stenosis is an abnormal narrowing in a blood vessel or other tubular organ or structure.It is also sometimes called a stricture ....

, particularly of saphenous vein
Great saphenous vein
The great saphenous vein , also long saphenous vein, is the large superficial vein of the leg and thigh.The terms "safaina" and "el safin" have both been claimed as the origin for the word "saphenous."-Path:The GSV originates from where the dorsal vein of the first digit...

grafts due to atherosclerosis
Atherosclerosis
Atherosclerosis is a condition in which an artery wall thickens as a result of the accumulation of fatty materials such as cholesterol...

causing recurrent angina or myocardial infarction
Myocardial infarction
Myocardial infarction or acute myocardial infarction , commonly known as a heart attack, results from the interruption of blood supply to a part of the heart, causing heart cells to die...

.
Acute renal failure
Acute renal failure
Acute kidney injury , previously called acute renal failure , is a rapid loss of kidney function. Its causes are numerous and include low blood volume from any cause, exposure to substances harmful to the kidney, and obstruction of the urinary tract...

due to embolism or hypoperfusion.
Stroke
Stroke
A stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...

, secondary to embolism or hypoperfusion.
Vasoplegic syndrome
Vasoplegic syndrome
Vasoplegic syndrome is a postperfusion syndrome characterized low systemic vascular resistance and a high cardiac output.-Definition:Vasoplegic syndrome is defined as low systemic vascular resistance within the first 4 postoperative hours.-Causes:VPS occurs more frequently after on pump CABG...

, secondary to cardiopulmonary bypass and hypothermia
Grafts last 8 – 15 years, and then need to be replaced.
Pneumothorax
Pneumothorax
Pneumothorax is a collection of air or gas in the pleural cavity of the chest between the lung and the chest wall. It may occur spontaneously in people without chronic lung conditions as well as in those with lung disease , and many pneumothoraces occur after physical trauma to the chest, blast...

: An air collection around the lung that compresses the lung
Hemothorax
Hemothorax
A hemothorax is a condition that results from blood accumulating in the pleural cavity.-Cause and presentation:Its cause is usually traumatic, from a blunt or penetrating injury to the thorax, resulting in a rupture of the serous membrane either lining the thorax or covering the lungs...

: Blood in the space around the lungs
Pericardial Tamponade: Blood collection around the heart that compresses the heart and causes poor body and brain perfusion. Chest tube
Chest tube
A chest tube is a flexible plastic tube that is inserted through the side of the chest into the pleural space. It is used to remove air or fluid , or pus from the intrathoracic space...

s are placed around the heart and lung to prevent this. If the chest tube
Chest tube
A chest tube is a flexible plastic tube that is inserted through the side of the chest into the pleural space. It is used to remove air or fluid , or pus from the intrathoracic space...

s become clogged in the early post operative period when bleeding is ongoing this can lead to pericardial tamponade, pneumothorax
Pneumothorax
Pneumothorax is a collection of air or gas in the pleural cavity of the chest between the lung and the chest wall. It may occur spontaneously in people without chronic lung conditions as well as in those with lung disease , and many pneumothoraces occur after physical trauma to the chest, blast...

or hemothorax
Hemothorax
A hemothorax is a condition that results from blood accumulating in the pleural cavity.-Cause and presentation:Its cause is usually traumatic, from a blunt or penetrating injury to the thorax, resulting in a rupture of the serous membrane either lining the thorax or covering the lungs...

.
Pleural Effusion
Pleural effusion
Pleural effusion is excess fluid that accumulates between the two pleural layers, the fluid-filled space that surrounds the lungs. Excessive amounts of such fluid can impair breathing by limiting the expansion of the lungs during ventilation.-Pathophysiology:...

: Fluid in the space around the lungs. This can lead to hypoxia
Hypoxia (medical)
Hypoxia, or hypoxiation, is a pathological condition in which the body as a whole or a region of the body is deprived of adequate oxygen supply. Variations in arterial oxygen concentrations can be part of the normal physiology, for example, during strenuous physical exercise...

which can slow recovery.

General cardiac surgery

Post-operative atrial fibrillation
Atrial fibrillation
Atrial fibrillation is the most common cardiac arrhythmia . It is a common cause of irregular heart beat, identified clinically by taking a pulse. Chaotic electrical activity in the two upper chambers of the heart result in the muscle fibrillating , instead of achieving coordinated contraction...

: An arrhythmia that sometimes occurs after cardiac surgery.

General surgical

Infection
Infection
An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...

at incision sites or sepsis
Sepsis
Sepsis is a potentially deadly medical condition that is characterized by a whole-body inflammatory state and the presence of a known or suspected infection. The body may develop this inflammatory response by the immune system to microbes in the blood, urine, lungs, skin, or other tissues...

.
Deep vein thrombosis
Deep vein thrombosis
Deep vein thrombosis is the formation of a blood clot in a deep vein. Deep vein thrombosis commonly affects the leg veins or the deep veins of the pelvis. Occasionally the veins of the arm are affected...

(DVT)
Anesthetic
Anesthesia
Anesthesia, or anaesthesia , traditionally meant the condition of having sensation blocked or temporarily taken away...

complications such as malignant hyperthermia
Malignant hyperthermia
Malignant hyperthermia or malignant hyperpyrexia is a rare life-threatening condition that is usually triggered by exposure to certain drugs used for general anesthesia; specifically, the volatile anesthetic agents and the neuromuscular blocking agent, succinylcholine...

.
Keloid
Keloid
A keloid is a type of scar, which depending on its maturity, is composed mainly of either type III or type I collagen. It is a result of an overgrowth of granulation tissue at the site of a healed skin injury which is then slowly replaced by collagen type 1...

scarring
Chronic pain
Chronic pain
Chronic pain has several different meanings in medicine. Traditionally, the distinction between acute and chronic pain has relied upon an arbitrary interval of time from onset; the two most commonly used markers being 3 months and 6 months since the initiation of pain, though some theorists and...

at incision sites
Chronic stress
Chronic stress
Chronic stress is the response to emotional pressure suffered for a prolonged period over which an individual perceives he or she has no control. It involves an endocrine system response in which occurs a release of corticosteroids...

related illnesses
Death
Death
Death is the permanent termination of the biological functions that sustain a living organism. Phenomena which commonly bring about death include old age, predation, malnutrition, disease, and accidents or trauma resulting in terminal injury....

External links

A BBC film showing a patient undergoing a double bypass operation.
Ischemic Heart Disease section in Cardiac Surgey in the Adult
Coronary Artery Bypass Surgery at NYU Langone Medical Center's Cardiac and Vascular Institute

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.