Coronary Artery Disease affects 13 million Americans each year. Coronary artery diseases occurs when plaques form in the coronary artery’s. These plaques consist of calcium, fatty compounds, cholesterol, and various blood clotting components Formation of these plaques in the arteries narrows their lumen, decreasing the amount of oxygen and nutrient rich blood reaching the heart. This decrease in blood flow to the heart is called ischemia, and can result in a heart attack (myocardial infarction).
The coronary arteries originate from the aorta just above the aortic valve. There are 3 coronary arteries the left anterior descending artery (LAD), the left circumflex artery (LCx) and the right coronary artery (RCA). The LAD and the LCx have a common origin from the left main coronary artery. Each of these arteries may have branches as shown.
Coronary artery bypass surgery (CABG) is the most common cardiac surgical preformed. Albany Cardiothoracic Surgeons perform over 300 CABG’s each year.
The goal of coronary artery bypass surgery is to get more blood around narrowings and blockages in the coronary arteries. This will provide the heart with more oxygen and nutrients and decrease ischemia. Surgeons accomplish this by removing blood vessels from one part of the body and reattaching them to the heart, constructing new pathways for blood to get around the blockages in the native arteries. Successful completion and recovery from bypass surgery will relieve patients of their angina symptoms, decrease risk of a heart attack, decrease shortness of breath and congestive heart failure, decrease fatigue, and in some cases increase survival.
Coronary bypass surgery is performed under general anesthesia, so patients are completely asleep. After administration of the anesthetic the heart is exposed by dividing the sternum (breast bone). The blood vessels to be used for bypass; the saphenous vein, radial artery, internal thoracic artery are removed and prepared for use. Patients are then placed on the heart lung machine. The heart lung machine does the work of the heart and lungs while surgeons operate on the heart. The heart is stopped and surgeons attach the new blood vessels to arteries on the heart beyond the blockages using fine sutures. The other end of the grafts are attached to another vessel in the chest (aorta) or to the internal thoracic artery to provide a new source for blood flow into the heart. Once the bypasses are finished the heart is allowed to restart and patients are taken off the heart lung machine. Following closure of all incisions patients are take to intensive care unit for recovery.
Conduits (Blood vessels) for Coronary Artery Bypass Surgery
Internal Thoracic Artery (ITA): Also known as the internal mammary artery (IMA). These vessels are found on each side of the sternum. Most commonly the left ITA is used for bypassing the left anterior descending artery. Once dissected from the chest wall the left ITA (LITA or LIMA), is detached at its distal end to be used for bypass. The proximal end is left in its natural anatomic position.
Saphenous Vein: The saphenous vein is located in the leg. The vein is found superficially, under the skin. Because we have a second and larger vein deep in the leg musculature to provide for blood return to the heart, the saphenous vein can be utilized without many adverse affects. The veins are removed using either an open or endoscopic technique. In the open technique, a long or multiple incisions are made in the leg and the vein dissected out using direct visualization. In the endoscopic technique, a small incision is made near the knee, and a telescope and video visualization is used to dissect the vein. Endoscopic vein harvest results in more patient comfort with a lower risk of infection and less swelling in the extremity. The saphenous vein grafts once removed are attached proximally to the aorta and distally to the coronary artery.
Radial Artery: The radial artery is located in the forearm. It is the artery felt when a pulse is taken in the wrist. The radial artery is often attached to the left ITA or aorta proximally and distally to the coronary artery.
Coronary artery bypass can be performed with either venous or arterial conduits. However, over time saphenous vein grafts tend to develop the same type of atherosclerotic changes which are present in the native arteries. Because of this surgeons have turned to using arterial grafts for as many bypasses as possible. The left ITA is the most commonly used arterial graft. It is commonly used to bypass the left anterior descending artery. Use of an arterial graft for this specific bypass has been found to give the best long term result with patency rates approaching 95% at 10-15 years. The radial artery or right ITA can be used to bypass other arteries. Often they are attached to left ITA to make a T shaped graft (T-graft). This technique enables surgeons to perform a complete arterial revascularization of the heart. Extensive use of arterial revascularization has been associated with a decrease risk of further intervention as compared to vein grafts or percutaneous intervention. The greatest benefit is in younger patients. Surgeons for Albany Cardiothoracic Surgeons have extensive experience in using arterial grafts. Almost 99% of patients receive one arterial grafts and 40-50% receive more than one arterial graft.
Transmyocardial Laser Revascularization (TMR)
Transmyocardial laser revascularization is a procedure where a carbon dioxide laser is used to drill small channels into the heart muscle. With time these channels allow more blood to reach the heart muscle and can decrease angina. TMR is useful when the blood vessels are too small or badly diseased to be bypassed. It is often used in addition to bypass but can performed without bypass grafts. The best results with TMR are obtained when it used in patients with good heart muscle function, who are having angina, and don’t have blood vessels which can be bypassed.
Off Pump Bypass Surgery
Conventional surgery for coronary artery disease has utilized the heart lung machine (cardiopulmonary bypass). This has allowed surgeons to perform surgery on the heart in a still and bloodless field. Newer advances in surgical devices have allowed surgeons to perform surgery without the use of cardiopulmonary bypass (off pump or beating heart surgery). Although many advantages of off pump surgery have been proposed, large studies have not been shown it to be more advantageous.
The heart has four valves, the tricuspid, pulmonary, mitral, and aortic. Heart valves are designed to direct the flow of blood through the heart in one direction. Blood coming from the upper and lower extremities enters the heart through the right atrium. It then goes through the tricuspid valve into the right ventricle. From the right ventricle it is pumped through the pulmonary valve into the lungs. The carbon dioxide is removed and the blood is oxygenated in the lungs. Oxygenated blood from the right and left lungs then collects in the left atrium. It then passes through the mitral valve into the left ventricle. Blood is pumped out of the left ventricle through the aortic valve to the entire body.
Various diseases can affect heart valves. Heart valves can be affected in one of three ways:
- Stenosis or narrowing of the valve opening. In this process the valve cannot fully open to allow blood to leave from one chamber to the next. When valve stenosis occurs blood has to be more forcefully pushed out of from one chamber to the next. This usually results in the one chamber enlarging, and increasing in muscle mass.
- Regurgitation or insufficiency is when the valve is unable to close properly. This allows blood to leak back from one chamber to the previous chamber. The overload of blood can cause that chamber to enlarge to accommodate the excess blood.
- Combination of stenosis and regurgitation. In this condition the valve can neither open nor close effectively. Thus blood has to be forcefully pushed out and then some of it will leak back.
Aortic Valve Disease
The aortic valve is composed of three crescent shaped leaflets, which are attached to a rim of tissue (annulus) between the aorta and the left ventricle. Normally the valve opens with each heartbeat, allowing blood to leave the left ventricle and go to rest of the body. As the heart beat ends, the valve closes and preventing blood from returning to the heart. The leaflets are thin and pliable, however with disease this anatomy can change. The leaflets may narrow, obstructing the flow of blood out of the heart, they may not close properly allowing blood to flow back into the heart, or a combination of these two. All these conditions cause the heart to work harder and increase in size. Eventually the heart is unable to keep up with the increased demands and begins to fail. Patients may experience this as shortness of breath, lightheadedness, or chest discomfort. Valve replacement can help reverse this process, decrease symptoms, and increase longevity.
The aortic valve can be damage by various diseases. A degenerative process due to aging, infection, rheumatic fever, and congenital defects are the most common causes. One percent of the population is born with a valve with two leaflets (bicuspid) rather than three (tricuspid). Most of these valves develop changes by the fifth or sixth decade, which may require replacement.
Aortic valve replacement is accomplished with a prosthetic valve. Two types of prosthetic valves are utilized. A mechanical valve is made of inert non-biologic tissue. It has a low profile design and can last for many years without structural deterioration. A disadvantage is the lifelong requirement for anticoagulation (blood thinners). Biologic valves (bioprosthetic) are made of specially treated biologic tissue, which makes them immunologically inert. Biologic valves have the advantage that anticoagulation is not needed. However the biologic tissue may deteriorate (over 15-18 years) with time causing the valve to fail. For this reason biologic valves are most commonly used in individuals over the age of 65.
St. Jude Medical Mechanical Valve
Edwards Bovine Bioprosthetic Pericardial Valve
Surgical Technique for Aortic Valve Replacement
Aortic valve replacement requires the use of a general anesthetic. Patients are placed on the heart lung machine by placing catheters in the aorta and right atrium. The heart-lung machine does the work of the heart and lungs so that blood can be redirected from the heart. Once the patient is placed on the heart lung machine a clamp is placed on the aorta to stop blood flow into the heart. This allows surgeons to work on a motionless heart devoid of blood. The aortic valve is exposed by opening the ascending aorta. The diseased valve leaflets are removed. Sutures with Teflon felt bolsters (pledgets) are placed along the rim of tissue where the native valve was once attached. Sutures are then passed through the prosthetic valve. Prosthetic valve is then secured in place by tying the sutures. The aorta is then closed and the clamp removed from the aorta. This allows blood flow to resume to the heart and the heart begins to beat. Any air is evacuated from the heart; the support of the heart lung machine is withdrawn. Temporary pacing wires are placed, drainage tubes inserted, and the incisions are closed. The patient is then taken to the intensive care unit for recovery.
Mitral Valve Disease
The mitral valve is a complex structure between the left atrium and left ventricle. It is the second most common valve requiring surgical intervention. The valve is composed of two leaflets attached to fibrous tissue in the heart. The leaflets also have fine chords and muscular attachments to the left ventricle. In addition to valve function these structures can affect left ventricular function and shape. Blood coming from the lungs collects in the left atrium, passes through the valve into the left ventricle. Normal functioning of the valve prevents blood from going back into the left atrium when the left ventricle contracts.
Various diseases can damage the mitral valve causing stenosis, regurgitation, or both. Rheumatic fever and degenerative changes are the most common causes of mitral stenosis. Valve leaflets become thick, less pliable, resulting in stenosis. In order to force blood through the narrowed orifice, the left atrium increases in size and becomes more muscular. Eventually the high pressures generated in the left atrium will be transmitted to the lungs, resulting in shortness of breath. Degenerative changes, infection, heart attack and rheumatic fever are the most common causes of mitral regurgitation. With each beat a quantity of blood leaks back into the left atrium. The increased volume of blood in this chamber eventually causes it to enlarge. With time there will also be a larger volume of blood ejected into the left ventricle, causing this chamber to dilate. If the process is allowed to continue it will result in shortness of breath and heart failure. Repair or replacement of the valve can improve symptoms, longevity, and heart muscle function.
The mitral valve can be replaced with a prosthetic valve. Two types of prosthetic valves are utilized. A mechanical valve is made of inert non-biologic tissue. It has a low profile design and can last for many years without structural deterioration. A disadvantage is the lifelong requirement for anticoagulation (blood thinners). Biologic valves (bioprosthetic) are made of specially treated biologic tissue, which makes them immunologically inert. Biologic valves have the advantage that anticoagulation is not needed. However the biologic tissue may deteriorate (over 12-15 years) with time causing the valve to fail. For this reason biologic valves are most commonly used in individuals over the age of 65.
The mitral valve can also be repaired. Surgeons have developed a variety or techniques to repair the valve based on the anatomic changes causing regurgitation. These techniques often involve removing a damaged portion of the valve leaflet, followed by reconstruction of the remaining valve. Placing a prosthetic ring around the valve completes the valve repair. The ring supports the repair and prevents further dilatation of the valve. Valve repair has the advantage of preserving the native valve and its anatomic attachments to the left ventricle. This results in better long term function of the left ventricle. Long term anticoagulation is also not required with valve repair decreasing the risk of bleeding complications. Thus when possible valve repair is preferable to valve replacement.
Surgical Technique for Mitral Valve Repair/Replacement
Depending on the structural changes that occur, the mitral valve can be either replaced or repaired. The procedure is performed using general anesthesia. Once the patient is asleep, the heart is exposed. Patients are placed on the heart lung machine by placing catheters in the aorta and right atrium. The heart-lung machine does the work of the heart and lungs so that blood can be redirected from the heart. Once the patient is placed on the heart lung machine a clamp is placed on the aorta to stop blood flow into the heart. This allows surgeons to work on a motionless heart devoid of blood. The mitral valve is most commonly exposed through the left atrium. Once exposed the valve and its supporting structures are carefully examined to determine if the valve can be repaired or replaced.
If the valve is to be replaced, the leaflets are excised. Depending on the extent of damage to the valve attempts are made to preserve either one of the leaflets and/or the fine chordal attachments of the valve. Preservation of these structures helps maintains better function of the left ventricle. Sutures with Teflon felt bolsters (pledgets) are passed through the rim of tissue left after valve excision and through the new valve. Sutures are then tied securing the valve in place. Depending on the patient’s age either a mechanical or bioprosthetic valve can be used.
If the valve is to be repaired, this is completed and a ring is sutured around the valve. After the repair is completed, competency of the valve is tested. This is accomplished by passively filling the left ventricle and observing for any leakage through the valve.
Once the valve is replaced or repaired, the left atrium is closed and the clamp removed from the aorta. This allows blood flow to resume to the heart and it begins to beat. Air is evacuated from the heart; support of the heart lung machine is withdrawn. The valve repair is once again reviewed using echocardiography to ensure a satisfactory repair. Temporary pacing wires and drainage tubes are placed and the incisions are closed. The patient is taken to the intensive care unit for recovery.
Minimally Invasive Heart Valve Surgery
The goal of minimally invasive valve surgery is to approach the valves through smaller incisions. This approach offers better cosmesis than the standard midline incision, while maintaining the quality of the valve surgery. Minimally invasive incisions are often 6-8 cm (3-4 in) in length and they maybe on the side of the chest (thoracotomy or Heartport) or in the midline (partial sternotomy). In the thoracotomy incision the chest is entered between the ribs. It provides good access to the valves, however alternative methods have to be used to place the patient on the heart lung machine. This is most commonly is done by using blood vessels in the groin (femoral artery and vein). In the partial sternotomy incision, only the upper part of the breast bone is split. Access for the heart-lung machine can often be done using blood vessels in the chest when this incsion is used.
Although the major advantage of a minimally invasive incision is cosmetic, other advantages may include:
- Less pain
- Less blood loss
- Less risk of bone infection
- Faster recovery
It is important to note that not all patients are candidates for minimally invasive valve surgery. Patients with obesity, concomitant coronary artery disease, or severe atherosclerosis in groin and abdominal blood vessels are not good candidates.
Tricuspid Valve Surgery
The tricuspid valve prevents reflux of blood from the right ventricle to the right atrium. Tricuspid insufficiency can lead to swelling (edema) of the extremities and fatigue. Our surgeons are experienced in tricuspid valve repair and replacement.
A number of different disease processes can lead to end-stage heart disease and congestive heart failure. Some of these, such as massive heart attacks, are acute, while others may progress chronically. When the heart fails, sources of adjunctive mechanical support can be life-saving. These are commonly referred to as “Ventricular assist devices,” or “VADs.” We offer a number of different devices that provide variable degrees of circulatory support for the failing heart. These may function as bridge to recovery, heart transplant or destination therapy.
Atrial fibrillation impacts an estimated 2.2 million Americans, and affects roughly 6% of patients over the age of 65. Many of these patients suffer from associated valve disease, especially mitral insufficiency. Atrial fibrillation can cause strokes, and can cause chronic fatigue and shortness of breath. Our surgeons at Albany Cardiothoracic Surgeons are well-versed in the Cox-Maze IV procedure, which is an ablative procedure usually performed in conjunction with another heart operation to eradicate atrial fibrillation.
Many patients suffer from varying degrees of heart block, which occurs when there is damage to the hearts conduction system. Pace makers are fully implantable, battery-driven devices which restore the heart’s rhythm Via an electrical impulse. Our surgeons are qualified in placing pace makers via the traditional transvenous approach as well as through various chest incisions.
A very small percentage of patients might develop an associated pace maker infection sometime during one’s lifetime. This can only be effectively treated by completely removing the device. We offer laser lead extraction, which is a minimally invasive approach to removing the pacemaker and its leads.